INTERNATIONAL SOUND AND VIBRATION DIGEST Published by THE INTERNATIONAL INSTITUTE OF ACOUSTICS AND VIBRATION (IIAV) Volume 3, Number 2 Date: 24 June 1997 Editor-in-Chief: Malcolm J. Crocker, Auburn University, USA Assistant Editor: Dragana Obradovic, Auburn University, USA Editorial Board: Duan-shi Chen, Jiao Tong University, Shanghai, CHINA Frank Fahy, ISVR, Southampton University, UK Jean L. Guyader, INSA de Lyon, FRANCE Colin H. Hansen, University of Adelaide, AUSTRALIA Hanno Heller, DLR, Braunschweig, GERMANY Yoshihiko Irie, Nagasaki, JAPAN Nikolay Ivanov, Baltic State University, St. Petersburg, RUSSIA Finn Jacobsen, Technical University of Denmark, DENMARK G. Krishnappa, Institute for Machinery Research, NRC, CANADA Conny Larsson, Uppsala University, SWEDEN Leonid M. Lyamshev, Andreev Acoustics Institute, Moscow, RUSSIA Dan B. Marghitu, Auburn University, USA Eric Marsh, Penn State University, USA M.L. Munjal, Indian Institute of Science, Bangalore, INDIA David E. Newland, The University of Cambridge, UK Michael P. Norton, University of Western Australia, AUSTRALIA A. Selamet, Ohio State University, USA Andrew F. Seybert, University of Kentucky, Lexington, USA M.O. Tokhi, University of Sheffield, UK Jan W. Verheij, TNO, Delft, THE NETHERLANDS. Current number of subscribers: 1051 To send a submission to the IS&V DIGEST or to subscribe or unsubscribe, send information by E-mail to yanas@eng.auburn.edu. TODAY'S DIGEST CONTENTS ITEM 1. INTRODUCTION. ITEM 2. IIAV-AFFILIATED SOCIETY: The Korean Society for Noise and Vibration Engineering. ITEM 3. NEW BOOK ANNOUNCEMENT: Encyclopedia of Acoustics. ITEM 4. CONFERENCE ANNOUNCEMENT: Asia-Pacific Vibration Conference. ITEM 5. CONFERENCE ANNOUNCEMENT: "Acoustique & Techniques," Paris, France, 20 June, 1997. ITEM 6. IJAV EDITORIAL APPOINTMENT ITEM 7 FELLOWSHIPS: EPSRC Awards. ITEM 8. NATIONAL ACOUSTIC LABORATORIES, SYDNEY. ITEM 9. RESEARCH IN ACTIVE SOUND AND VIBRATION CONTROL AT THE UNIVERSITY OF SHEFFIELD ITEM 10. RECENT DOCTORAL THESES: 1) Multi-dimensional adaptive signal processing; 2) Self-tuning active noise control systems. ITEM 11. NEW RESEARCH RESULTS FOR HIGH FREQUENCY SCATTERING. ITEM 12. CONFERENCE ANNOUNCEMENT: The Fifth International Congress on Sound and Vibration. ITEM 13. CALL FOR PAPERS: First CEAS-ASC Workshop on Wind Tunnel Testing in Aeroacoustics. ITEM 14. BOOK REVIEW: Collected Papers of Sir James Lighthill. ITEM 15. TECHNICAL PAPER: Prediction of Vibration Amplitudes for Defective Rolling Bearings ITEM 16. IIAV: Membership Application Form ITEM 17. CONFERENCE ANNOUNCEMENT AND CALL FOR PAPERS ******************************************************************************* ITEM 1. INTRODUCTION. ******************************************************************************* We are pleased to bring you this issue of the ISV DIGEST. The DIGEST is now being published by the INTERNATIONAL INSTITUTE OF ACOUSTICS AND VIBRATION (IIAV). The digest is free of charge to members of the IIAV. The IIAV is a new democratic international scientific society and membership, as member or associate is open to individuals from all countries. So far over 250 individual members have joined from 38 different countries. In addition 14 scientific societies have become affiliated with the IIAV. On behalf of Sir James Lighthill, of London, England, the first President of IIAV, and the officers and directors, it is my pleasure to invite you to consider becoming a member if you are not already. Members receive, as part of their annual dues of $80, not only the DIGEST but also a refereed journal the INTERNATIONAL JOURNAL OF ACOUSTICS AND VIBRATION (IJAV) which began publication in December 1996. Non-IIAV members and libraries can subscribe to the JOURNAL (IJAV) for $100 per year by airmail, post paid. As the IIAV membership grows, additional services will be provided for IIAV members. It is planned to make full use of all modern electronic means of communication to assist members in the future. Complete details about IIAV are available on the worldwide web at http://www.iiav.org A membership application form is enclosed as ITEM 16 of this issue. It can be submitted by e-mail, fax or airmail. Those interested in the recently published Encyclopedia of Acoustics should note that Wiley has extended the reduced price of $395 until June 30, 1997 (see ITEM 3). As discussed in earlier issues of the DIGEST, plans are already well underway for the Fifth International Congress on Sound and Vibration. It will be held at the University of Adelaide, at Adelaide in South Australia, December 15-18,1997. The General Chairman is Professor Colin Hansen. He has planned an excellent technical program, and we hope that you will put this date on your calendar and make plans to attend. We are sure that you will enjoy a genuine Australian welcome with great hospitality. If you are interested in receiving further details about the Fifth Congress, Colin Hansen will be pleased to send them when you write by air mail: Department of Mechanical Engineering University of Adelaide, GPO Box 498, Adelaide, 5005, Australia, FAX: 61-8-303-4367 or e-mail: chansen@mecheng.adelaide.edu.au. You can also find further details and a congress registration form on the Web at http://www.icsv5.on.net Over 425 abstracts have been received from 38 countries for the Fifth Congress. We advise reserving your air travel to Australia well ahead of time; reservations may be difficult to obtain for December 1997 because it is the Australian summer. Complete congress details, registration forms, etc. for the congress can be found in ITEM 19 at the end of the March, 1997 DIGEST (Volume 3, Number 1), at http://www.icsv5.on.net or via http://www.iiav.com. The proceedings of the previous four congresses are still available. Details were given in the December 1996 DIGEST. If you are interested in further information, please write to yanas@eng.auburn.edu. We are pleased to inform you that back issues of the ISV Digest are available on the Auburn University Gopher (Academic Areas and Departments-College of Engineering-Department of Mechanical Engineering). Beginning November 18, 1996, back issues of the ISV Digest have been made available on Auburn University web under http://www.auburn.edu/isvd. We hope that you are finding the ISV DIGEST useful. We should be interested to hear your comments and to receive news items and technical information and articles for inclusion in the next issue. We hope to bring out the next issue of the DIGEST in September 1997, so don't forget to send your items soon! These should be sent to yanas@eng.auburn.edu. Malcolm J. Crocker Editor-in-Chief ******************************************************************************* ITEM 2. NEW IIAV-AFFILIATED SOCIETY ******************************************************************************* IIAV-Affiliated Society The Korean Society for Noise and Vibration Engineering The Korean Society for Noise and Vibration Engineering(KSNVE) was founded in July 1990, with the participation of members interested in noise and vibration engineering from various specialties such as: mechanical, aeronautical, ocean, civil, architectural, electrical, environmental engineering. KSNVE is a non-profit scientific society established by individual members in order to promote industrial development through advancing the arts and sciences in the field of noise and vibration engineering. The Society, consisting of over 1,400 members including 36 cooperative and 28 group members, covers broad fields of educational and technical activities in noise and vibration engineering, and is one of the most active professional societies in Korea, maintaining a strong tie with Korean industry. The KSNVE became affiliated with IIAV in March 1997. Research studies on various noise and vibration engineering problems as well as codes/standards are frequently conducted by ad hoc research committees with funds from government, foundations, and industries. Continuing education and training programs, symposia, and programmed lectures are conducted regularly by four technical divisions within the Society: machinery, environment, construction and transportation. This year's topics are: modal testing techniques, evaluation of ride quality, construction noise /architectural acoustics, environmental effect of noise /vibration due to high speed train operation, instrumentation /evaluation techniques, noise/vibration testing of transportation systems, etc. Various publishing operations are conducted by the Society. Noise and Vibration, the official bimonthly magazine of the KSNVE, speaks for the Society, and disseminates new information on engineering and technology, including about 20 articles of general interest and over 100 technical papers annually. Biannual proceedings of the Society contain technical papers presented at the Spring and Fall annual conferences. About 100 papers were presented at the Spring annual conference held recently. The Society is also proud of the recent publication of the Noise and Vibration Handbook. In addition, many workshop /seminar /symposia materials are published regularly by the technical divisions. ******************************************************************************* ITEM 3. NEW BOOK ANNOUNCEMENT ******************************************************************************* Encyclopedia of Acoustics, Four Volume Set Edited by Malcolm J. Crocker, Department of Mechanical Engineering, Auburn University The most comprehensive coverage of acoustics in over 100 years to set the standard for the next millennium Now there's a new four-volume reference that covers every imaginable area of acoustics, sound, and vibration --- from the design of a concert hall to the intricacies of the human ear. It's the Encyclopedia of Acoustics. In this one-of-a-kind set, edited by well-known acoustical expert Dr. Malcolm J. Crocker, you'll get: Extensive cross-referencing and indexing 2,000-plus pages of insights from more than 200 international expert contributors An exhaustive examination of the fundamentals of acoustics and vibration in the first two volumes A revealing exploration of acoustic applications in Volumes Three and Four General introductions at the start of every section This up-to-date work is sure to become the definitive acoustics resource for students, engineers, scientists, and researchers in the field. 0471-80465-7 (Four Volume Set) Cloth 2,000 pp. April 1997 $475.00 A reduced price of $395 is being offered for IIAV members and Digest subscribers, if ordered by June 30, 1997. To order your copy, please email kbernick@wiley.com or send your order to: Katherine Bernick John Wiley & Sons, Inc. 605 Third Avenue New York, NY 10158, USA In the USA you can also order copies by telephone 1-800-225-5945 or by fax at 1-212-850-6103. Please add your local sales tax and a $2.50 handling fee. Overseas you can order by fax 1-212-225-5945 or e-mail kbernick@wiley.com ******************************************************************************* ITEM 4. CONFERENCE ANNOUNCEMENT: Asia-Pacific Vibration Conference '97. ******************************************************************************* ASIA-PACIFIC VIBRATION CONFERENCE '97 The Asia-Pacific Vibration Conference (A-PVC'97) will be held in Kyongju, Korea, from November 9 to 13, 1997. The conference is organized and sponsored by Division of Dynamics and Control and The Korean Society of Mechanical Engineers; co-sponsored by Japan Society of Mechanical Engineers; Institution of Engineers, Australia; Chinese Mechanical Engineering Society; Institution of Engineers, Malaysia; and the Korean Society for Noise and Vibration Engineering. The past conferences were successfully held in Japan (1985 & 1993), Korea (1987), China (1989), Australia (1991), and Malaysia (1995). Now, the Organizing Committee is pleased to announce that so far, about 270 abstracts have been received from 13 countries. TOPICS Acoustic Dynamics & Control, Active Control of Sound, Computational Technique, Control & Measurement in Mechanical Systems Damping, Dynamics in Robotics, Dynamics & Modeling in Biology, Dynamics of Machines & Structures, Dynamics of Nonconservative Systems & Controlled Structure, Dynamics of Plant Structures & Systems, Dynamics of Space Structures, Electromagnetic Forces & Application, Fuzzy Control & Neural Network, Impact Dynamics, Machine Condition Monitoring, Modal Analysis & Identification, New Trends in Continuous System Dynamics, Nonlinear Vibration & Chaos, Noise & Acoustics, Precision Dynamics & Control, Random Vibrations, Rotor Dynamics, Seismic Engineering, Sound Source Identification, Vehicle Dynamics & Control, Vibration Control and Other Related Topics. IMPORTANT DATES April 1, 1997: Date for submission of abstracts June 1, 1997: Notification of acceptance August 1, 1997: Date for submission of camera-ready manuscript. OFFICIAL LANGUAGE The official language of the conference is English. VENUE CITY- Kyongju As the capital city of the Shilla Kingdom(B.C.57-A.D.935), Kyongju was the center of a golden period of Korean culture. The city of Kyongju was chosen by the UNESCO as one of the 12 historical sites of the world. The remains of the brilliant culture of the Shilla Kingdom are preserved or rebuilt as they were. Kyongju is called a "Museum without walls" as the royal tombs, stone pagodas, palaces and Buddhist temples still remain scattered throughout the city. The two Buddhist treasures of Kyongju are Pulkuksa Temple, one of the most beautiful temples in Korea, and Sokkuram (a stone grotto) known all over the world for the stone statues and carved friezes. Kyongju allows you to experience a living history and to feel the excellent world of art as well as the ups and downs of the history. CLIMATE AND DRESS Korea lies in the temperate zone and has four distinct seasons: spring, summer, fall and winter. Fall begins from September and lasts until November. The weather will be rather chilly and the temperature will be in the range of 4-8 degrees C (38-46 degrees F) during November. You will need a warm jacket or sweater. Also bringing a rain coat or umbrella is recommended. For further information please contact: The Secretariat of A-PVC'97 c/o INTERCOM Convention Service Inc. 4Fl. Jisung Bldg. #645-20 Yoksam 1-dong, Kangnam-gu Seoul 135-081, Korea Phone: +82-2-3452-1444, 566-6339 Fax: +82-2-3452-7292, 565-2434 E-mail: intercom@soback.kornet.nm.kr Chong-Won Lee Director, Center for Noise and Vibration Control (NOVIC) Professor, Department of Mechanical Engineering KAIST Science Town, Taejon 305-701 South Korea e-mail: cwlee@hanbit.kaist.ac.kr http://novic.kaist.ac.kr TEL: +82-42-869-3016 FAX: +82-42-869-8220 ******************************************************************************* ITEM 5. CONFERENCE ANNOUNCEMENT ******************************************************************************* The French technical journal "Acoustique & Techniques" held a meeting on the "Acoustical Quality of Aircraft" during the 42nd International trade show on aeronautics and aerospace of Paris-Le Bourget, France, June 20, 1997. Detailed information on the meeting is available at the following website: or by contacting directly: Dr. Pascal Millot Acoustique & Techniques - Scientific Editorial Board ----------------------- E-mail: millotp@adbc.fr ******************************************************************************* ITEM 6. IJAV EDITORIAL APPOINTMENT ******************************************************************************* Editorial Appointment: In an Executive Committee meeting of the IIAV on 25 March 1997 in London, chaired by Sir James Lighthill and attended by David Newland (Vice President) and Malcolm Crocker (Executive Director), Dr. Osman Tokhi of the University of Sheffield, UK was appointed as Associate Editor of the International Sound and Vibration Digest and Subject Area Editor on Active Noise and Vibration Control of the International Journal of Acoustics and Vibration (IJAV). Papers on Active Noise and Vibration Control for IJAV should be submitted to Osman Tokhi for review in the future. ******************************************************************************* ITEM 7. FELLOWSHIPS: EPSRC Awards ******************************************************************************* EPSRC CASE Awards: The following two new awards are available at the Department of Automatic Control and Systems Engineering, The University of Sheffield, UK. (1) Noise and echo cancellation of telephone systems. (2) Intelligent automatic speech recognition. Both awards are for a duration of three years, each leading to the degree of Ph.D. These are supported by Aculab Plc, an established company in computer telephony and speech recognition. Only UK/EC students are eligible to apply. Further details can be found on the web site: http://www.sheffield.ac.uk/academic/A-C/. Informal inquiries can also be made by email on 'o.tokhi@sheffield.ac.uk'." ******************************************************************************* ITEM 8. NATIONAL ACOUSTIC LABORATORIES, SYDNEY ******************************************************************************* The National Acoustic Laboratories in Sydney, Australia, have just commenced an interesting project on wind noise. Turbulence associated with wind flowing past a hearing aid produces noise at the output of the hearing aid. Little or no data are available to quantify how much wind noise is generated by the head, parts of the outer ear, or the hearing instrument... The spectral shape of the noise generated also warrants investigation. A home-made and a commercial wind tunnel can assist in these measurements, although the background noise of the tunnel fan's motor / blades is not ideal. An alternative would be a device which moves (e.g. a platform on wheels) to provide a relative wind past the head. A review of literature which discusses wind noise in microphones, the spectral content of wind turbulence and the interaction between air turbulence and wind noise production will be a preliminary step in this project. We would appreciate any references or comments which would assist the literature review, or any other aspect of this research. contacts: Dr. Harvey Dillon (Harvey.Dillon@nal.gov.au) Inge Roe (Inge.Roe@nal.gov.au) -------------------------------------------------------------------- National Acoustic Laboratories 126 Greville St, Phone: +61 2 9412 6828 Chatswood, 2067, or +61 2 9412 6889 Australia Fax: +61 2 9411 8273 -------------------------------------------------------------------- ******************************************************************************* ITEM 9. RESEARCH ON ACTIVE SOUND AND VIBRATION CONTROL AT THE UNIVERSITY OF SHEFFIELD ******************************************************************************* The Active Sound and Vibration Control (ASVC) Research Group at the University of Sheffield, Department of Automatic Control and Systems Engineering was formed in 1989. The group currently comprises Dr. M O Tokhi (as director), a research fellow and five Ph.D. research students. Two further academic members of the department currently contribute to the activities of the group through their involvement in relevant collaborative projects. Moreover, on average, 5-6 MSS and undergraduate students per year car ry out their projects within the group. 1. PROGRAMS OF RESEARCH The main areas of research covered by the ASVC research group are * Active Noise Control. * Active Vibration Control. * Dynamic Modeling and Recognition of Speech. * Intelligent/Adaptive Control. * Parallel Processing. * Real-time Signal Processing and Control. These are reflected within the group's current programmes of research, briefly highlighted below 1.1. Intelligent/Adaptive active noise and vibration control. Active control of noise/vibration is realized by artificially generating canceling source(s) of noise/vibration through detecting and processing the unwanted sound by a suitable electronic controller. In practice, the characteristics of sources of noise/v ibration and of electronic sensors and transducers used vary, e.g. due to operating conditions, leading to time-varying phenomena. Under such circumstances an active noise/vibration control system is required to have the capability of adapting to such var iations so that the desired level of performance is achieved and maintained. The aim of this programme is to develop intelligent adaptive active control schemes for noise cancellation and vibration suppression of compact sources using single- and multiple-source configurations. Projects currently in progress under this programme are * Self-tuning active noise and vibration control. * Active noise control using neural networks. * Active vibration control using genetic algorithms. 1.2. Control of vibration of flexible structures. Due to the performance demands of modern control systems, the utilization of high speed and light weight structures is favored. However, this leads to increased problems of induced vibration in the system. The performance demands and safety constraints of such systems, in many cases, do not allow the use of passive techniques to absorb the oscillatory energy and/or to use stiffer structure to approach rigid body motion. Active control provides a suitable alternative in these situations. The aim of this pr ogramme is to develop active vibration control strategies to suppress motion-induced vibrations in flexible structures. Projects currently in progress under this programme are * Simulation and control of single-link flexible manipulator systems. * Control of vibration of flexible beam structures. * Active control of bearing vibration of rotating systems. 1.3. Analysis and design of active noise control systems. Active noise control (ANC) uses the intentional superposition of acoustic waves to destructively interfere with one another and thus result in a reduction in the unwanted sound. In this manner, the interference of the component waves leads to a pattern of zones of cancellation and reinforcement so that noise is reduced at some locations and reinforced at others. Moreover, depending on the geometrical configuration of system components, practical limitations in the controller design as well as instability due to acoustic feedback are encountered. This programme is looking at investigating the physical extent of cancellation achieved by active means for given system geometry and number of sources in three-dimensional propagation, the robust design of such s ystems in due consideration of stability and practical realization of the controller design. 1.4.Modeling and recognition of speech Current systems for speech recognition and coding are based on simplistic models of speech dynamics. These are defined in terms of multi-dimensional representations of speech. Thus, the development of model(s) which would adapt to suit the local statistic s of such multi-dimensional representations would result in an improvement in the recognition and coding of speech. Moreover, these models can be appropriate to other forms of multi-dimensional data, such as compression of still images. This programme looks at investigating and developing intelligent methodologies for dynamic modeling and automatic recognition of speech. Current projects in progress under this programme are * Multi-dimensional adaptive signal processing. * Gender recognition using speech signals. 1.5. High-performance parallel architectures for real-time signal processing and control The performance demands of modern control systems often exceed the capacity of conventional microprocessors and require parallel solutions for real-time performances. Appropriate matching of hardware granularity to task size is essential to fully exploit the computational power available. It is therefore inevitable that this parallel architecture is a heterogeneous one. The aim of this research is to integrate a variety of processors, such as MIMD machines, DSPs and programmable gate arrays within a unifi ed architecture for complex signal processing and control applications. The approach involves the development of a software environment to support the design, implementation and testing of such architectures. Projects currently in progress under this programme are * Heterogeneous architectures for parallel real-time control. * Digital signal processing and parallel processing for real-time control applications. * Performance evaluation and design tools for heterogeneous parallel architectures. * Comparative study of different implementations of a Doppler signal spectral estimator. 1.6. Hybrid functional electrical stimulation (FES): Assistive technology for the handicapped. The most significant deficit following spinal cord injury (SCI) is the loss of mobility. Spinal cord trauma or disease may result in an incomplete or complete functional inability to stand up and to walk. Therefore, SCI patients are confined to a wheelcha ir for managing their daily life activities. Considerable effort is directed towards hybrid assistive systems to re-establish functional movement in handicapped people. This project looks at investigating the development of hybrid FES gait restoration sys tems that combine electrical stimulation with an externally controlled mechanical brace. An important objective of the work is to ensure stability and trajectory control of the lower limbs. 2. PROFILE AND ACHIEVEMENTS The following Ph.D. research programmes of the group have successfully been completed during the last three years * A K M Azad (September 1994): Analysis and design of control mechanisms for flexible manipulator systems. * M A Hossain (May 1995): Digital signal processing and parallel processing for real-time adaptive noise and vibration control. * L Baghai-Ravary (December 1995): Multi-dimensional adaptive signal processing with application to speech recognition, speech coding and image compression. * K Mamour (October 1996): Analysis and design of multiple-source self-tuning active noise control systems. In addition to a book on active noise control, the group has contributed extensively through publications in journals, conference presentations and internal research reports. The total number of papers published during 1994, 1995 and 1996 are 20, 33 and 32 respectively. The group in the past has carried out projects funded by the Engineering and Physical Sciences Research Council (EPSRC), The British Council, the European Commission (EC) and other sources. The group is engaged in several collaborative research programmes with institutions at national and international level. Among these the group is part of an international network formed under the ALFA scheme of the EC. For further information/correspondence you may contact Dr. Osman Tokhi, M' IIAV Department of Automatic Control and Systems Engineering, The University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK. Tel: +44 (0)114 222 5617. Fax: +44 (0)114 273 1729. email: o.tokhi@sheffield.ac.uk ******************************************************************************* ITEM 10. RECENT DOCTORAL THESES ******************************************************************************* (1) Title: Multi-dimensional adaptive signal processing with application to speech recognition, speech coding and image compression Author: L. Baghai-Ravary Date: December 1995. Institution: The University of Sheffield, UK. Supervisor: Dr. M. O. Tokhi Department of Automatic Control and Systems Engineering, The University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK. Tel: +44 (0)114 222 5617. Fax: +44 (0)114 273 1729. email: o.tokhi@sheffield.ac.uk. ABSTRACT A new framework for analyzing dynamic structure in vector sequences has been devised and applied to a number of speech representations and image data. This allows a more complete separation of predictable and unpredictable components of such non-stationar y data. In speech recognition and coding this is beneficial to accuracy and compression ratio respectively. The new methods can give about 15% reduction in error rate for phoneme recognition, 30% for isolated words, and can yield a compression ratio of ov er 50%, with barely-noticeable levels of distortion. In image compression it makes the design of the vector quantiser codebook, used in conventional techniques, more straightforward. It is shown to give about 70% compression alone, and nearly 90% compress ion in conjunction with standard image coding techniques, even when applied to complex images. The work describe in this thesis represent a completely new approach to adaptive signal processing. However, every attempt has been made to present this work in the context of existing techniques so that the advantages it offers can be demonstrated more explicitly. (2) Title: Analysis and design of multi-source self-tuning active noise control systems Author: K. Mamour Date: October 1996. Institution: The University of Sheffield, UK. Supervisor: Dr. M. O. Tokhi Department of Automatic Control and Systems Engineering, The University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK. Tel: +44 (0)114 222 5617. Fax: +44 (0)114 273 1729. email: o.tokhi@sheffield.ac.uk. ABSTRACT This thesis presents the development of multi-source self-tuning active noise control (ANC) mechanisms for cancellation of broadband noise in a three-dimensional non-dispersive propagation medium. A quantitative measure of cancellation in terms of source and geometry related parameters of the system is obtained and used to establish conditions of cancellation in the medium. A three-dimensional description of the interference pattern created by the system in the medium is obtained and merits of ANC system design as related to the geometrical arrangement of system components are described. An ANC system is designed on the basis of optimum cancellation at a set of observation points in the medium using a single-input multi-output feedforward control structure. Practical issues of design of the system in relation to the geometrical arrangemen t of system components, stability and time-variation are discussed. The controller design relations are formulated such that to allow on-line design and implementation of the controller, leading to an adaptive ANC mechanism. The adaptive ANC system thus d eveloped is tested within a free-field propagation environment and its performance in cancellation of broadband noise verified. ******************************************************************************* ITEM 11. NEW RESEARCH RESULTS FOR HIGH FREQUENCY SCATTERING ******************************************************************************* NEW RESEARCH RESULTS FOR THE FAST NUMERICAL CALCULATION OF HIGH-FREQUENCY ACOUSTIC SCATTERING FROM COMPLEX STRUCTURES M. Ochmann* and S. N. Makarov** *Technische Fachhochschule Berlin, Fachbereich Mathematik und Physik,Luxemburger Strasse 10, 13353 Berlin, Germany. E-mail: ochmann@tfh-berlin.de ** Faculty of Mathematics and Mechanics, State St. Petersburg University, Bibliotechnaya, 2, St. Petersburg-Petrodvoretz 198904, Russia. E-mail: makarov@niimm.spb.su The high-frequency scattering of incident plane waves by mainly non-convex complex structures is calculated using an iterative algorithm. The starting point of the computation is the Helmholtz integral equation which is transformed into a selfadjoint equation following an idea of Kleinman et al. [1,2]. This formulation can be solved iteratively where the convergence of the iteration process against the true solution is ensured due to the selfadjointness of the problem. As initial pressure p0 the plane wav e approximation (PWA) is used since it is an approximate solution at high frequencies like the Kirchhoff approximation or the Rayleigh integral [3]. As expected, fast convergence could be observed for all investigated structures, also equipped with diffe rent surface impedances. The possibility of using an iterative solver is of strong advantage for structures consisting of many thousand elements N since the computing time of the iterative solver is proportional to the square of N instead of the cube for a direct solver. Firstly, the scattering from rigid and impedance spheres with radius a consisting of nearly 6000 elements is investigated at the non-dimensional wave number ka = 20.9. In this case, a comparison with the analytical solution is possible and shows the following: The PWA as the zeroth iteration gives acceptable results only for the rigid sphere where the difference from the exact solution does not exceed 4 dB. The iterative solver excellently agrees with the exact solution at any value of the surface impeda nce: the difference does not exceed 0.4 dB for the rigid sphere and 1.5 dB otherwise. To achieve the so-called discretization error 7-16 iterations are necessary. The main object of our investigation is a non-convex structure which consists of a sphere where the positive octant (i.e. the part corresponding to x>0, y>0, z>0) is cut out. The region of the missing octant is called ,cat's-eye" since it acts like a thre e-dimensional reflector. Hence, depending on the angles of incidence multiple reflections can occur. The surface is either rigid, or has a finite constant impedance , or is only partially rigid and is equipped with an absorbing coating within the reflecting area of the cat's-eye. Three such structures with the same geometry but with a different number of boundary elements (7911, 24832, and 57470) are considered to achieve large values of ka until 62.8. In such a case, high-frequency approximations like th e PWA fail since multiple scattering appears. But, starting with the PWA, a small number of iterations gives a very accurate solution for the scattering problem. A new developed C++ computer code allows to perform all calculations on ordinary personal computers - including the biggest model with 57470 boundary elements. These positive results encourage us to extend the iteration method to radiation problems and to the computation of sound fields in arbitrary closed rooms in the near future. A detailed description of the presented work can be found in a paper which has recently been submitted for publication in the Journal of the Acoustical Society of America [4]. Also, these results will be presented at the Internoise 97 in Budapest [5]. References [1] R. E. Kleinman, G. F. Roach, and L. S. Schuetz, and J. Shirron, "An iterative solution to acoustic scattering by rigid objects," J. Acoust. Soc. Am., 84, 385-391 (1988). [2] R. E. Kleinman and G. F. Roach, "Iterative solutions of boundary integral equations in acoustics," Proc. Roy. Soc. L., A417, 45-57 (1988). [3] M. C. Junger and D. Feit, Sound, structures, and their interaction, The Massachusetts Institute of Technology, Edward Brothers Inc., Cambridge, 1972. [4] S. N. Makarov and M. Ochmann, "An iterative solver of the Helmholtz integal equation for high-frequency scattering" (submitted for publication in the JASA). [5] M. Ochmann and S. N. Makarov ,A fast iterative method for the calculation of high-frequency scattering from complex structures," will appear in the Congress report of the Internoise 1997 in Budapest. Full address of Prof. Dr. Martin Ochmann: Technische Fachhochschule Berlin, Fachbereich Mathematik und Physik, Luxemburger Str. 10, D-13353 Berlin, Germany Tel.: 0049 30 4504 2931, Fax: 0049 30 4504 2974; email: ochmann@tfh-berlin.de ******************************************************************************* ITEM 12. CONFERENCE ANNOUNCEMENT: Fifth International Congress on Sound and Vibration ******************************************************************************* FIFTH INTERNATIONAL CONGRESS ON SOUND AND VIBRATION University of Adelaide, Adelaide, South Australia, AUSTRALIA December 15-18, 1997 CONGRESS TECHNICAL PROGRAMME The Congress technical programme includes seven distinguished plenary keynote addresses, eight specialist keynote addresses, seven two-hour specialist tutorials and invited and contributed papers in specialized areas of sound and vibration. The Fifth Congress follows previous congresses held in the USA, Canada and Russia in 1990, 1992, 1994 and 1996. Several hundred people attended each previous congress and over 425 abstracts have been received already for the 5th Congress. AIRLINE RESERVATIONS These must be made NOW as December is a busy time for travel to Australia and available seats are already filling fast. Be sure to also take out travel insurance as medical treatment is very expensive. DISTINGUISHED KEYNOTE PAPERS The following distinguished keynote addresses will be presented in plenary sessions. "A Century of shock wave dynamics" Sir James Lighthill, UK "Helicopter rotor aeroacoustics" Hanno Heller, Germany "Recent developments in acoustics" Malcolm J. Crocker, USA "Vibration suppression through smart damping" Dan Inman, USA "Active control of structurally radiated sound" Chris Fuller, USA "Developments in digital analysis techniques for diagnostics of bearings and gears" Bob Randall, Australia "Hearing protectors: are they the cheapest and quickest solution?" Samir Gerges, Brazil CONTRIBUTED PAPER ABSTRACTS (over 425 in total) covering theoretical and experimental research in the following areas have been received: Active noise control Active vibration control Aeroacoustics Architectural acoustics Boundary element and finite element methods Condition monitoring and diagnostics Damping - passive and active Environmental/community noise Human response to sound and vibration Inverse methods Low frequency noise and vibration Machinery noise and vibration control Materials for noise and vibration control Measurement techniques Mechanisms of human hearing Modal analysis Musical acoustics Noise control elements Non-destructive testing Non-linear acoustics and vibration Numerical methods Occupational noise exposure and control Outdoor sound propagation Scattering of sound Signal processing Sound intensity Sound sources Sound transmission Statistical energy analysis Structural acoustics and vibration Structural intensity Transportation vibration and noise Underwater acoustics Vibration and shock Vibration sources Wavelet analysis SCIENTIFIC COMMITTEE (CHAIR: Malcolm J. Crocker) Robin Alfredson, Australia David Bies, Australia Simon Braun, Israel Norm Broner, Australia Marion Burgess, Australia Christian Carme, France Alan Cummings, UK Zbigniew Engel, Poland Graeme Finch, New Zealand Neville Fletcher, Australia Chris Fuller, USA Samir Gerges, Brazil Barry Gibbs, UK Stewart Glegg, USA Richard Guy, Canada Jean Louis Guyader, France Uwe Hansen, USA Hanno Heller, Germany Ken Heron, UK Hugh Hunt, UK Dan Inman, USA Nickolay Ivanov, Russia Finn Jacobsen, Denmark Adrian Jones, Australia Krish Krishnappa, Canada B. Andrew Kugler, USA Sen Kuo, USA Joseph Lai, Australia Nick Lalor, UK Sir James Lighthill, UK Joseph Mathew, Australia Gopal Mathur, USA Jag Mazumdar, Australia Antonio Mendez, Argentina Hideo Minamihara, Japan Yasuo Mitani, Japan M.L. Munjal, India David Newland, UK Kam Ng, USA Michael Norton, Australia Mitsuo Ohta, Japan Jie Pan, Australia M. G. Prasad, USA P.K. Raju, USA Yitshak Ram, Australia Bob Randall, Australia David Rennison, Australia Scott Snyder, Australia Scott Sommerfeldt, USA David Swanson, USA Nobuo Tanaka, Japan Osman Tokhi, UK Jan Verheij, Netherlands M. Wahab, Australia Hugh Williamson, Australia Graeme Yates, Australia PUBLICATIONS The deadline for receipt of abstracts is now past. Contributed papers will be published in Proceedings as full 8-page papers and will be available as paper copy as well as on CD-ROM. All written papers and lecture presentations will be in English. EXHIBITION Companies are invited to take part in the exhibition which now has over twenty exhibitors. There are very few booth spaces left. The exhibition will include instrumentation and electronics, acoustical apparatus and materials, sound and vibration isolation devices and software. Exhibition information and booth reservations are available from the Congress Secretariat. SOCIAL PROGRAM The University of Adelaide is located close to the entertainment centre of a city with over one million people. Adelaide is well known for its lack of traffic jams, cleanliness and clean air as well as for parks and gardens, pure beaches and natural wild life parks. It is recognized as Australia's leader in high tech industry and is also close to the premier wine producing areas of Australia. Special, unique excursions and activities have been arranged for delegates and accompanying persons before during and after the Congress. These are detailed in the registration brochure available on the Congress Home Page on the Web. LODGING Participants will be accommodated in a number of hotels within 15 minutes walk of the University. Accommodation costs will vary from $AUD30 per night for student style accommodation (non-airconditioned, shared facilities) to $AUD160 per double for a 5 star hotel. Details of accommodation at reduced congress rates are available in the registration brochure which will be sent by the Congress Secretariat on request and which may also be viewed on our home page. All accommodation is a short drive (15 mins) from the International airport and is easily accessed by shuttle bus or taxi. FURTHER INFORMATION The Congress registration fee is $460 AUD for members of IIAV and $540 for others for registration prior to May 30, 1997. For registration between May 30, 1997 and November 10, 1997, the fees are $490 AUD for members of IIAV and $570 AUD for others. For registration after November 10, the fees are $570 AUD for members of IIAV and $650 AUD for others. The registration fee includes a copy of the proceedings, a reception and an Australian BBQ in a natural wild-life park. Please make checks or bankdrafts p ayable in Australian dollars drawn on an Australian bank for the registration fee payable to "5th Congress" and mail to the Congress Secretariat. Alternatively, payment may be made by VISA or MASTERCARD, if you quote your card number, expiration date and provide a signature (please use the registration form to register). ****************************************************************************** ITEM 13. CALL FOR PAPERS: First CEAS-ASC Workshop on Wind Tunnel Testing in Aeroacoustics ****************************************************************************** Call for Abstracts First CEAS-ASC Workshop on Wind Tunnel Testing in Aeroacoustics 5-6 Nov. 1997 DNW, Noordoostpolder, The Netherlands Scientific co-chairmen: Dr. G. Fournier and Dr. H. Heller Local hosts: Prof. H.U. Meier and Dr. H. Brouwer The Aeroacoustics Specialists' Committee (ASC) of the Confederation of European Aerospace Societies CEAS announces its first international workshop on Wind Tunnel Testing in Aeroacoustics to be held at the German-Dutch Wind Tunnel DNW. The event is to outline the state-of-the-art in this field and to discuss the very latest achievements in Wind-Tunnel testing techniques, particularly important in aeroacoustics. Dedicated to this very purpose the workshop will provide a unique possibility of scientific exchange among the participants. Scope of the workshop ================= Aeroacoustics has recently seen a very strong re-newed interest in the understanding and reduction especially of airframe noise in addition to the more traditional field of propulsion noise. The prediction of airframe noise depends heavily on model or full scale wind tunnel research, due to the lack of accurate theoretical methods. Since the seventies, the period of most intense investigations in this field, many new testing techniques have been developed and considerably improved. The scope of the workshop is the development and application of advanced aeroacoustic testing techniques in wind tunnels. Although the topics are primarily intended to be embedded into the frame of aerospace science and technology, contributions from the field of exterior noise of trains, cars and wind turbines are equally welcome. The first CEAS-ASC Workshop on Wind Tunnel Testing in Aeroacoustics will cover - source localization techniques (acoustic arrays and mirrors) - correlation between local unsteady flow and radiated sound - comparison of model and full-scale testing - suppression of microphone self noise - test-section reverberation and background noise - noise transmission through shear layers - signal processing The workshop will be organized into formal presentations with an abstract being the only written material required. At the meeting a folder will be available containing the abstracts and copies of the viewgraphs shown. As opposed to other meetings the workshop is to have an informal character. No parallel sessions are planned and comparatively much time will be given for questions in order to stimulate an intense discussion. Submission of abstracts ================== Abstracts of about 200 words including names and addresses of authors should be submitted by 31 July 1997. Authors will be informed of acceptance/rejection by 30 August 1997. Copies of viewgraphs to be shown at the workshop should be sent by 17 October 1997. The time available for the presentation of each paper will be 30 minutes including discussion. Abstracts and viewgraphs are to be sent to the workshop secretariat (see below). Scientific Committee =============== G. Fournier ONERA, chairman CEAS-ASC 1997-98 H. Heller DLR, chairman CEAS-ASC 1995-96 H.U. Meier DNW, local host H. Brouwer NLR, local host P.G. Garcia-Fogeda University of Madrid R. Pinker DERA G. Guj University of Rome III I.U. Borchers DASA Dornier Key Dates ======== Receipt of abstracts: 31 July 1997 Notification of Authors: 30 Aug. 1997 Preliminary Programme issue: 15 Sept. 1997 Submission of copies of viewgraphs: 17 Oct. 1997 Workshop Secretariat ================ c/o NLR Mr. Pieter Kluit Anthony Fokker Weg 2 1059 CM Amsterdam The Netherlands Tel.: +31 20 511 3244 Fax: +31 20 511 3210 e-mail: Kluit@nlr.nl For further information contact Hanno Heller, e-mail: Hanno.Heller@dlr.de ******************************************************************************* ITEM 14. BOOK REVIEW: Collected Papers of Sir James Lighthill ******************************************************************************* COLLECTED PAPERS OF SIR JAMES LIGHTHILL, Edited by M. Yousuff Hussaini, Oxford University Press, New York, ISBN 0-19-509222-8, 2688 pages, 4 volumes, cloth, $400 (US), 1997. Sir James Lighthill is one of the great applied mathematicians of the 20th century having made very important contributions in the understanding of jet noise. However his scientific contributions are much broader than many may be aware. His important seminal papers in aeroacoustics in the 1950's and 1960's are perhaps best known particularly by those of us with a background in mechanics and/or acoustics. However, he has also published important papers in astrophysics, atmospheric and oceanographic sciences, biofluidmechanics, and fluid mechanics including shock wave theory. Like other important scientists (Lord Rayleigh comes to mind) Sir James Lighthill invariably gives a first rate account of each topic he approaches. His papers are characterized by elegance, insight and lucidity and normally involve three important steps: problem formulation using observation or empiricism, problem solution, and finally interpretation of the results. We are fortunate that Oxford University Press has chosen to publish Sir James' collected papers in four volumes and hope that since Sir James remains very active that a fifth volume will follow in due course. The four volumes presently include 90 journal papers, keynote addresses, review articles, book chapters and some important internal reports (we note that 57 books and miscellaneous other papers and works have not been included for various reasons). Volume I contains his major contributions to high speed flows including reentry aerodynamics, magnetohydrodynamics and an astrophysical application to the solar atmosphere. Volume II contains his papers on aerodynamics of bodies in inviscid compressible flows with or without vorticity, boundary layer theory both in subsonic and supersonic flows, and on chaotic motions. Volume III contains Sir James Lighthill's papers on wave motion including his important papers on aeroacoustics published in 1952 when Sir James was at Manchester University. These papers contain his famous acoustic analogy in which the Navier Stokes equations are manipulated into an inhomogeneous wave equation with a non-linear right hand side with terms that are treated as acoustic source terms. Volume IV contains Lighthill's papers on biological fluid dynamics (both external and internal) and collects together many of his important papers on bird, bat and insect flight, theories for the swimming of fish, and fluid mechanics in the inner ear (cochlea). It is hoped that some of the recent studies that Sir James Lighthill has conducted on tropical cyclones, volcanoes and earthquakes will be included in a fifth volume in the future. Malcolm J. Crocker ******************************************************************************* ITEM 15. TECHNICAL PAPER ******************************************************************************* PREDICTION OF VIBRATION AMPLITUDES FOR DEFECTIVE ROLLING BEARINGS N. Tandon and A. Choudhury ITMME Centre, Indian Institute of Technology, Hauz Khas, New Delhi - 110016, India e-mail : ntandon@itmmec.iitd.ernet.in Abstract : Importance of the study of amplitudes of significant frequency components of the vibration spectra of defective rolling bearings has been stated. The authors' approach towards prediction of amplitudes for various types defects has been reported. A comparison among these amplitudes concludes the paper. 1. INTRODUCTION Vibration produced by defective rolling element bearings has drawn the attention of the researchers for a long time. Rolling bearing defects may be categorized as localized or distributed. The localized defects include cracks, pits or spalls caused primarily due to fatigue on the rolling surfaces. The distributed defects, on the other hand, include surface roughness, waviness, misaligned races and off-size rolling elements resulting from manufacturing error and abrasive wear. Therefore, vibration response due to localized defects is important for condition monitoring and system maintenance where as the response from distributed defects is necessary for quality inspection as well as condition monitoring. Vibration response from bearings can be measured in both time and frequency domain. The time domain approach utilized the measurement of overall rms level, crest factor and some statistical parameters like probability density and kurtosis [1,2]. The frequency domain approach which essentially means the spectral analysis of vibration signal has become more popular with the advent of FFT ( fast Fourier transform ) analyzers. The frequency spectra obtained from a defective bearing contain peaks at the 'characteristic defect frequencies' of various bearing elements and can thus readily identify whether the defect is on the outer race, inner race or on a rolling element. These frequencies appear in the low frequency zone. The expressions for significant frequency components for a localized defect are well- established [3,4,5]. The frequency spectra from distributed defects under various loading and defect conditions have also been studied by several researchers [6-9]. However, it has been found that many of these defect frequencies of localized and distributed type, coincide with each other. As a result it becomes difficult to identify from frequency information whether the peak at a particular frequency is due to localized or distributed defect. Hence a study of the amplitude in addition to the frequency information of vibration response of defective bearings assumes importance [10]. Meyer et al.[6] proposed a model to predict vibratory displacement of races due to distributed defects on the moving race or on the rolling elements under axial load. Expressions were derived for radial displacement of the stationary bearing race. Based on that model, the authors derived expressions for amplitudes of significant frequency components for vibration of races due to distributed [11] and localized defects [12] under radial load. The approach made to obtain these results is being reported in this paper. A comparison of the amplitudes of frequency components due to various types of defects has also been made. 2. THE PROBLEM FORMULATION In this treatment, a bearing with stationary outer race and inner race rotating at the shaft speed (Ws), has been considered. In order to determine the vibration response, the bearing races are considered as isolated continuous systems subjected to external excitations caused by bearing defects. It is also assumed that the deflection pattern of the bearing races is the sum of sine and cosine waves around the races. The equation of motion for the races can be obtained with the help of Lagrange's equation, as applied to a continuous system. When a localized or point defect on one surface strikes its mating surface, a pulse of short duration is produced. These pulses which also depend on the load at the position of the defect, are assumed as the excitation for localized defects. For distributed defects, the excitation force is considered to be the contact force applied by rolling elements on the races. This contact force is time varying and defect dependent in nature. 3. VIBRATION RESPONSE DUE TO LOCALIZED DEFECTS The excitation force has been assumed as the product of the pulses generated due to the interaction of defect with mating element and the load at the position of interaction. Since the definite pulse forms are not known, therefore, some typical pulse forms (e.g. rectangular, triangular or half sine pulses) of arbitrary height have been considered. However, the pulse width can be determined from kinematic considerations [3]. The load applied by a rolling element on the races at any position can be obtained from [13]. The generated pulses are periodic in nature with periodicities being dependent on the position of the defect. Therefore, the expressions for the pulses can be expanded in Fourier series. Since a defect on the outer race remains stationary, therefore, the load at the position of the defect remains constant. But for a defect on the inner race or on a rolling element, its position and hence the load at that position change with time. Therefore, the load applied by a rolling element on the inner race defect or the load due to defective rolling element is periodic in nature having periodicity equal to cage frequency. Therefore, the resultant excitation force is a sum of the sine and cosine terms. The excitation force thus obtained can be substituted into the equations of motion and the response due to a single rolling element can be can be obtained by solving the equations. For a defect on a single rolling element, this is the resultant response. However, for obtaining the resultant response due to inner race defect and outer race defect, the response due to all the rolling elements have to be summed up linearly keeping in mind the phase difference among them. In the frequency domain, the responses have discrete spectra. For outer race defect, there will be peaks at 'outer race defect frequency'(Wor) and its multiples. For inner race defect and rolling element defect, the main peaks are at the 'inner race defect frequency'(Wir) and 'rolling element defect frequency' (Wre) respectively along with sidebands respectively at shaft frequency (Ws) and cage frequency (Wc) and their multiples. The amplitudes of all these components have also been derived [12].In the displacement mode, the amplitudes of the main peaks are almost equal and in case of inner race and rolling element defect, the sidebands are symmetrically distributed about the main peaks. 4. VIBRATION RESPONSE DUE TO DISTRIBUTED DEFECTS For distributed defects, the excitation force due to a rolling element can be assumed to be point loading due to contact force applied by the element and can be expressed with the help of Dirac delta function. The expression for the contact force applied by a rolling element on the races can be obtained from [13] and the same expression has been modified to incorporate the effects of waviness on inner and outer races and off-size rolling element [11]. Resultant response due to various types of defects can be obtained following the procedure adopted in case of localized defects. Due to relative motion between races and rolling elements and because of the races being continuous systems, vibration response of the races can be obtained even from a geometrically perfect bearing. The frequency spectrum has components at Wor and Wir and their multiples for responses from outer and inner races respectively. In case of inner race response, there are sidebands at Ws and its multiples about the peaks at Wir and its multiples. For outer race waviness, the response from the inner race is negligibly small in comparison to outer race response. Hence the frequency spectrum has peaks at Wor and its multiples. For inner race waviness, the response from outer race has peaks at Wor and sidebands on either side at mWs where m = number of full sine waves around the race. The inner race response has peaks at Wir and its multiples along with sidebands at Ws and its multiples. For off-size rolling elements, the outer race response has components at Wc and its multiples and the inner race response has components at relative frequency of shaft and cage (Ws - Wc) and its multiples. The amplitudes of all these components have been derived in [11]. 5. COMPARISON OF RESPONSES The expressions for frequencies and displacement amplitudes were applied to a 6002 deep groove ball bearing and the numerical results were obtained. The localized defect considered was of 150 micron width and the height of the generated pulse form was assumed to be 1 [12]. The distributed defects were race waviness of amplitude 5 microns and 5 sine waves around the race on both the races and a off-size rolling element oversized by 30 percent. The results show that for outer race defect of both distributed and localized nature, there are components at Wor and its multiples. In case of localized defect, the amplitudes for Wor and its higher multiples are almost equal where as for outer race waviness, the amplitudes of higher multiples of Wor are much smaller in comparison to the component at Wor. Even for inner race waviness or off-size rolling element, the outer race response may produce components at Wor and its multiples. However, magnitude of these components are much smaller than those due to outer race waviness. Moreover, for inner race waviness, there are sidebands at mWs on either side of the peak and for off-size rolling element, there are components at cage frequency and its multiples. The inner race response for waviness as well as local defect on inner race produce components at Wir and its multiples along with sidebands at Ws and its multiples. However, for localized defect the sidebands are evenly and symmetrically distributed about the main peaks but for inner race waviness no such symmetry was observed. 5. CONCLUSION The study shows that though spectral analysis of vibration signal is a very important tool bearing defect detection but only frequency information is not sufficient for exact location of the defect and its nature. Hence it is important that this information is supplemented by amplitudes of the significant frequency components. If the height and nature of the pulses generated due to interaction of localized defect with mating elements are ascertained, then the relative amplitudes of various components due to localized and distributed defects can be determined. REFERENCES [1] J. Mathew and R.J. Alfredson, "The Condition Monitoring of Rolling Element Bearings Using Vibration Analysis", J. Vib., Acoust., Stress Rel. Des. Trans. ASME 106, 447-453 (1984) [2] D. Dyer and R.M. Stewart, "Detection of Rolling Element Bearing Damage by Statistical Vibration Analysis", J. Mech. Des. Trans. ASME 100, 229-235 (1978) [3] T. Igarashi and H. Hamada, "Studies on the Vibration and Sound of Defective Rolling Bearings ( First Report : Vibration of Ball Bearings with One Defect )", Bull. JSME 25(204), 994-1001 (1982) [4] P.D. McFadden and J.D. Smith, "Model for the Vibration Produced by a Single Point Defect in a Rolling Element Bearing", J. Sound Vib. 96(1), 69-82 (1984) [5] Y.-T. Su and S.-J. Lin, "On Initial Fault Detection of a Tapered Roller Bearing : Frequency Domain Analysis", J. Sound Vib. 155(1), 75-84 (1992) [6] L.D. Meyer, F.F. Ahlgren and B. Weichbrodt, "An Analytic Model for Ball Bearing Vibrations to Predict Vibration Response to Distributed Defects", J. Mech. Des. Trans. ASME 102, 205-210 (1980) [7] C.S. Sunnersjo, "Rolling Bearing Vibrations - The Effects of Geometrical Imperfections and Wear", J. Sound Vib. 98(4), 455-474 (1985) [8] F.P. Wardle, "Vibration Forces Produced by Waviness of the Rolling Surfaces of Thrust Loaded Ball Bearings, Part 1 : Theory", Proc. Inst. Mech. Engrs. 202(C5), 305-312 (1988) [9] Y.-T. Su, M.-H. Lin and M.-S. Lee, "The Effects of Surface Irregularities on Roller Bearing Vibrations", J. Sound Vib. 165(3), 455-466 (1993) [10] Y.-T. Su and Y.-T. Sheen, "On the Detectability of Roller Bearing Damage by Frequency Analysis", Proc. Inst. Mech. Engrs. 207(Pt. C), 23-32 (1993) [11] A. Choudhury and N. Tandon, "A Theoretical Model to Predict Vibration Response of Rolling Bearings to Distributed Defects under Radial Load", J. Vib. Acoust., Trans. ASME, Accepted for publication [12] N. Tandon and A. Choudhury, "An Analytical Model for the Prediction of Vibration Response of Rolling Element Bearings Due to Localized Defects", submitted to J. Sound Vib. [13] T.A. Harris, "Rolling Bearing Analysis", John Wiley and Sons, New York (1966) ***************************************************************************** ITEM 16. THE INTERNATIONAL INSTITUTE OF ACOUSTICS AND VIBRATION (IIAV) ***************************************************************************** President: Sir James Lighthill,England; Vice Presidents: Hanno Heller, Germany and David Newland, England; Secretary: Jan W. Verheij, The Netherlands; Treasurer: Terry D. Scharton, USA; Executive Director: Malcolm Crocker, USA. The International Institute of Acoustics and Vibration (IIAV) incorporated in June 1995, is a non-profit scientific society whose membership is open to qualified individuals in all countries. At the present 230 individuals from 38 countries have become IIAV members. DIRECTORS: Duan-Shi Chen, China; Zbigniew Engel, Poland; Samir Gerges, Brazil; Jean Guyader, France; Colin H. Hansen, Australia; Finn Jacobsen, Denmark; G. Krishnappa, Canada; Leonid M. Lyamshev, Russia; Antonio M. Mendez, Argentina; M. L. Munjal, India; Michael P. Norton, Australia; Mitsuo Ohta, Japan; August Schick, Germany; and Andrew F. Seybert, USA; PURPOSE The Institute has been created to advance the science of acoustics and vibration by creating an international scientific society that is responsive to the needs of scientists and engineers in all countries whose primary interests are in the fields of acoustics and vibration. The Institute shall cooperate with scientific societies in all countries and with other international organizations with the aim of increasing information exchange by sponsoring, cosponsoring or supporting seminars, workshops, congresses and publishing or providing journals or other publications. The Institute will provide an electronic International Sound and Vibration Digest (ISVD) and a paper refereed journal (the International Journal of Acoustics and Vibration) for all members as part of their dues. MEMBERSHIP There are six classifications of membership in the Institute including: Fellow, Member, Associate, Student Member, Emeritus Member, and Honorary Fellow. All memberships entitle a member to receive the publications of the Institute and to attend Institute meetings. Those entitled to vote at Institute meetings are restricted to Fellows, Members and Emeritus Members. Fellows, Members, Emeritus Members and Honorary Fellows are eligible to hold office. Membership as Member is open to all those who have at least a baccalaureate degree or its equivalent from an accredited institution and who are employed or have been employed in an activity related to acoustics and/or vibration. Membership as Associate is open to all persons who wish to support and promote the activities of the Institute, but who do not meet the criteria for membership as Member. DUES The membership dues are $80 per year. Membership dues for those from some countries will be at a lower rate. Members will begin receiving the electronic ISVD and the journal immediately on joining the Institute. OFFICERS AND DIRECTORS The officers of the Institute are the President, the President-Elect, the Immediate Past President, the Vice President for Professional Relations, the Vice President for Communications, the Secretary and Treasurer. The President, President-Elect and Immediate Past President hold office for two years. The other officers hold office for four years. The directors of the Institute hold office for four years. The officers and directors are elected by the members of the Institute. COOPERATING SCIENTIFIC SOCIETIES The Institute recognizes that many scientific societies with interests in acoustics and/or vibration exist in different countries. It is the purpose of the Institute to supplement their activities and to cooperate with them for the good of scientists and engineers throughout the world. To that end, existing scientific societies will be encouraged to become affiliated with the Institute as cooperating member societies. IIAV MEMBERSHIP APPLICATION FORM If you are interested in joining the IIAV, please fill in the form and return it by fax or e-mail (see following). Application for:: ( ) Member ( ) Associate 1) Name: _____________________________________________________ 2) Address: ____________________________________________________________ Fax: _____________________ E-mail : ___________________________ 3) Degrees (Institutions and dates): ____________________________________________________________________________ 4) Employment (with dates ): _____________________________________________________________________________ 5) Signature & Date: _______________________________________________________ 6) Payment Form: ( ) Check Please send in US dollars drawn on US bank. ( ) Bank Transfer Auburn National Bank - Auburn, AL USA, Tel: 334 821 9200 ABA Number 062202574 - Account Number 10308743 ( ) Credit Card (Visa or Master Card only) Card Number _______________________________ Card Type & Expiration Date _______________________________ Please return this form to: Dr. Malcolm J. Crocker Executive Director Secretariat Office IIAV Dept. Mech. Eng. 201 Ross Hall Auburn University, AL 36849-5341, USA (Tel: 334-844-3310, FAX: 334-844-3306) e-mail: mcrocker@eng.auburn.edu ************************************************************************** ITEM 17. CONFERENCE ANNOUNCEMENT AND CALL FOR PAPERS ************************************************************************** The 52nd Meeting of the Society for Machinery Failure Prevention Technology (MFPT) will be held on March 30 - April 2, 1998 at Virginia Beach, Virginia, USA. Invitations have been extended for other societies to organize and present sessions in their name at this conference. The sponsors of MFPT 52 include the Office of Naval Research (ONR), Naval Surface Warfare Center (NSWC), U.S. Army Research Laboratory (USARL), National Aeronautics and Space Administration (NASA) and Naval Sea Systems Command (NAVSEA). The 1998 THEME, "Prognosis of Residual Life of Machinery and Structures", was chosen to highlight the need for more focus on prognosis in the development of the condition monitoring process. The Conference is trying to encourage some success stories or promising concepts in condition based prognosis. The Opening Session will feature Dr. Dara Childs, Director of the Turbomachinery Laboratory at Texas A&M University, as Keynote Speaker. Other distinguished invited speakers will cover current topics and pressing technical issues of special concern to the technical community. Special plenary lectures on timely topics will also be programmed. The technical sessions at MFPT 52 will be selected by the Technical Program Committee based upon the papers that are proposed. Abstracts may be submitted in any area that contributes to the prevention of machinery or structural failures. Paper topics include, but are not limited to, the following: (1) Prognosis Techniques and Residual Life Assessment (2) Signal Processing (3) Advanced Diagnostics techniques (4) Advanced and Integrated Sensor Technology (5) Successful Diagnostic and Prognostic Approaches (6) Advances in NDE for Machine Diagnostics (7) Applications of Neural Networks (AI) (8) Failure Analysis and Fault Detection (9) Computerized Maintenance Management (10) Root Cause Analysis Technology (11) Oil/Wear Particle Analysis (12) Advances in Diagnostics Technologies (13) Modal Testing & Diagnosis of Machinery (14) Tribology/Wear Prevention and Corrosion (15) Diagnostic Scenarios with a Progression to Failure The deadline for abstracts is Sept 2, 1997. If you require further information or wish to receive a Call for Papers contact MFPT Executive Director, Henry C. Pusey. Phone (703) 754-2234 FAX(703)754-9743; hcpusey@ix.netcom.com.