European Working Group on Acoustic Emission

About the European Working Group on Acoustic Emission
Compiled by Hartmut Vallen, November 7th, 2014.

Foundation and 40th anniversary

   The European Working Group on Acoustic Emission (EWGAE) was formed in 1972. The following historic overview is taken from “ACOUSTIC EMISSION WORKING GROUPS: FORUMS FOR TECHNOLOGY EXCHANGE AND DISSEMINATION”, by Tom Drouillard, given at International Conference on Acoustic Emission, AEWG-50/ICAE-6, at Lake Tahoe in 2007:

“On March 14, 1972, Dr. Adrian A. Pollock of Cambridge Consultants, England conducted the Institute of Physics Conference on Acoustic Emission at Imperial College in London; fifteen papers from throughout Europe and the United States were presented. This meeting brought together the key people of Europe already involved in AE research; from England: in addition to Dr. Pollock, Dr. Don Birchon at the Admiralty Materials Laboratory, Drs. Ian L. Mogford and Ian G. Palmer at Central Electricity Research Laboratories, Peter G. Bentley at Risley Engineering and Materials Laboratory of the U.K. Atomic Energy Authority, and Dr. Brian Harris at the University of Sussex; from Germany: Drs. Jürgen Eisenblätter and Peter Jax at Battelle-Institut; from France: Dr. Paul F. Dumousseau at the Centre Technique des Industries Mecaniques and M. Nicole Chretien and Dr. E.G. Tomachevsky at the Centre d'Études Nucléaires de Saclay, Commissariat a l'Energie Atomique; from Italy: Dr. M. Mirabile at Centro Sperimentale Metallurgico; from Denmark: Arved Nielsen at the Research Establishment Risø, Danish Atomic Energy Commission; and from the Netherlands: Dr. J.C.F. DeKanter at the Technische Hogeschool Delft.”

    During the closing session of EWGAE-30 in Granada in Sept. 2012 the 40th anniversary was celebrated in presence of Dr. Adrian Pollock, one of the founders of EWGAE. Adrian reported that a result of this meeting in March 1972 was the formation of the “European Stress Wave Emission Working Group”. Its first meeting was held in November 1972, at the Admiralty Materials Laboratory in England. Fifty people from seven countries attended. The second meeting, co-chaired by Drs. Eisenblätter and Jax, was held in September 1973, at Battelle-Institut in Frankfurt, Germany, at which the group adopted its present name, “European Working Group on Acoustic Emission”. Adrian finished his speech with a nice surprise: He handed over to EWGAE Chairperson Hartmut Vallen one tape and 5 CDs labelled “Inaugural ESWEWG Meeting”. In a nice email exchange after the conference Adrian clarified that the recording was made at the March 1972 meeting, what was the first-ever conference on AE in Europe, but not the first EWGAE conference. The tape was “rescued” from Arved Nielsen who found it in the library of the DAEC Research Establishmentr at Risoe, Denmark.

Here is link to the recordings on the CDs: Institute of Physics Conference on Acoustic Emission March 1972 at Imperial College in London 
           (password is required for download - please used 'Contact us' TAB or contact with Irek Baran in order to obtain password)

Here is link to the Constitution of  EWGAE

Standardization of AE in Europe within CEN TC138

    During the late 1970s and early 1980s, the Codes Subgroup of EWGAE published five codes of practice. In 1991, the work of this group was taken up by a new working group on AE (WG7) of TC138, the Technical Committee for standardization of NDT-principles within CEN. This working group is comprised of national representatives who have been nominated by their respective National Standardization Institutions. The first Convenor of WG-7 was Emilio Fontana of CISE, Italy. After his retirement in 2003, Peter Tscheliesnig of TÜV Austria was appointed and is serving as Convenor of the group. Since 2000, the following standards for AE, developed by TC138 WG7, have been published (year of latest edition shown):

    - EN 1330-9:2009 NDT - Terminology - Part 9: Terms used in AE testing
    - EN 13554:2011 NDT - AE - General principles (latest edition: 2011)
    - EN 13477-1:2002 NDT - AE - Equipment characterisation, Part 1: Equipment description
    - EN 13477-2:2010 NDT - AE - Equipment characterisation, Part 2: Verification of operating characteristics
    - EN 14584:2013 NDT - AE - Examination of metallic pressure equipment during proof testing - planar location of AE sources
    - EN 15495:2007 NDT - AE - Examination of metallic pressure equipment during proof testing - Zone location of AE sources
    - EN 15856:2010 NDT - AE - General principles of AE testing for the detection of corrosion within metallic surrounding filled with liquid
    - EN 15857:2010 NDT - AE - Testing of fibre-reinforced polymers - Specific methodology and general evaluation criteria

Currently in preparation:
    - prEN ISO 18081:2014 NDT - AE - Leak detection by means of acoustic emission
    - N217 In service AE monitoring of metallic pressure equipment and other structures – General requirements

    During the last 5 years, active members within the CEN TC138-WG7 were: P. Tscheliesnig (Convenor, Austria), C. Herve (France), J. Bohse, A. Mück and H. Vallen (Germany), A. Anastasopoulos (Greece), C. De Petris (Italy), E. Romero (Spain), H. Schoorlemmer (The Netherlands), L. Rogers, P. Cole and J. Burns (U.K.), I. Baran (Poland), V. Svoboda (Czech Republic).
    The European Standard for Qualification and Certification of NDT Personnel, EN_ISO 9712 (substitutes EN473) covers the AE testing method (abbreviation: AT) and defines details for education and certification.
    During 2005, the British Institute of Non-Destructive testing has established an Acoustic Emission Working Group to develop the Acoustic Emission sections of their PCN scheme which provides an international programme for the certification of testing, inspection and condition monitoring personnel which satisfies the requirements of numerous European and international standards. Members of this group include K Holford, T Bradshaw, D Mba, M Forde, Trevor Holroyd, Winfield Stewart, Ian Taylor, John O'Brien, R Reuben, Stuart Courtenay and Martin Peacock.
    All these Standards have significantly contributed to the acceptance of the AE testing method in Europe.
   In July 2014, also independent of TC138, the German Expert Committee AE of DGZfP published a new edition of Guideline SE2 “Verification of AE sensors and their coupling in the laboratory”. Involved in the development of this document were Dr. J. Bohse, Dr. A. Brunner, Dr. J. Eisenblätter, Dr. C. Große, DI S. Pirskawetz, Dr. M. Sause, DI G. Schauritsch, DI J. Sell, DI P. Tscheliesnig, DI H. Vallen.

   The increasing desire to exchange ideas and experience is reflected in the number of participants.
   AE Testing in Europe is now well established in several important areas of proof testing, in-service monitoring, corrosion and leak detection. Development of the technology continues to be driven by the needs of the industry to reduce inspection and maintenance costs while preserving its assets and personnel safety. The advancement of PC technology has positively influenced new developments in hardware and software for powerful and user-friendly testing equipment.

Thoughts about future directions

The following thoughts about future requirements and directions for AE which are worth to be considered are also taken from “ACOUSTIC EMISSION WORKING GROUPS: FORUMS FOR TECHNOLOGY EXCHANGE AND DISSEMINATION”, by Tom Drouillard, given at International Conference on Acoustic Emission, ICAE-5, at Lake Tahoe, in 2007:

  1. There is a need for a textbook and training manuals on AE, both of which should be translated into as many different languages as needed.
  2. I believe there is a need for the establishment of an international AE library or document center to house a complete collection of the world literature on AE and provide on-line search service... See http://quest.library.Illinois.edu/ae/opent1.asp
  3. We must make a concerted effort to educate the layman, and particularly people in management, in order to take the mystery out of AE and its applications. This could be accomplished by putting together a compendium of reports on AE applications for each industry.
  4. In research, we must explore the vast area of opportunity offered by the recent advancements in electronics and computers.
  5. In applications, we need to develop effective techniques to inspect nuclear reactors and civil structures, particularly bridges and earthquake-prone buildings. With the growing demand for electric power throughout the world, nuclear power plants are being planned. NDT, and especially AE, must be an integral part of this planning. Nuclear materials are forever and we can not afford to build and operate nuclear facilities with anything less than total quality control.
  6. We need to couple and expand AE with other NDT methods and physical phenomena, such as was done in combining AE and ultrasonic in developing the acousto-ultrasonic technique.
  7. We must learn to look outside the confines of traditional AE to meet the changing needs of the future. We have to realize that the AE frequency spectrum ranges from meter-size seismic events up into the MHz range of ultrasonic.
  8. The ultimate goal in AE health monitoring of materials and structures must be related to fracture mechanics and the identification of source mechanisms such as: crack propagation, fatigue failure, phase transformation, corrosion and stress corrosion cracking, twinning and inclusion fracture; structural failures such as: fracture in high stress areas or in defective welds versus heat-affected zone and base metal; and finally being able to sort out meaningful emission sources from noise sources.
  9. We need to start looking into the fundamental physics of acoustic wave generation and propagation. Based on Newtonian physics, wave modes are predictable and identifiable. Better understanding of these waves can lead to better understanding of fracture mechanics, flaw growth in materials and structures, and material properties themselves.
  10. We can no longer be satisfied to merely detect and report acoustic signals and events. Our goal must be to detect, identify, analyze, and quantify source mechanisms. Then AE will continue to be recognized as a valuable tool in the fields of metallurgy, structural engineering, naval architecture, aerospace, and geophysics. Remember, acoustic emission is the only NDT method to offer real-time, dynamic analysis of materials and structures while they are under service loads.
  11. The working groups are only as valuable as you make them. Their function is to provide the forum in which each of us may participate. By participation, we become the more informed. Every working group I have attended provided me with one or more ideas by which I could improve what I was doing or solve a problem. Each of us becomes a winner by participation in our working group. Don't be just a passive listener. Take an active roll by presenting papers, by participating in open discussion, asking questions, posing problems, and sharing reports of your work. Remember, it is important to have input from the full gamut of AE activity: research, development, and application.

The following table gives an overview of history of the EWGAE conferences held since 1972:

No. Year City Country Additional info
1st 1972 London UK
2nd 1973 Frankfurt Germany
3rd 1974 Ispra Italy Combined with Euratom
4th 1975 Secley France Combined with French AEC
5th 1976 Roskilde Denmark
6th 1977 Rome Italy
7th 1978 Risley UK
8th 1979 Dortmund Germany
9th 1980 Senlis/Paris France
10th 1981 Winterthur Switzerland
11th 1982 Milano Italy
12th 1983 Cologne West Germany
13th 1984 Harwell UK
14th 1985 Lyon France
15th 1986* Istambul Turkey
16th 1987* London UK Combined with ECNDT
17th 1988 Scheveningen Holland
18th 1989 Vienna Austria
19th 1990 Erlangen Germany
20th 1992* Leuven Belgium
21st 1994 Nice France Combined with ECNDT
22nd 1996* Aberdeen UK
23rd 1998* Vienna Austria
24th 2000* Senslis/Paris France
25th 2002* Prague Czech Republic
26th 2004* Berlin Germany
27th 2006* Cardiff UK
28th 2008* Kraków Poland
29th 2010* Vienna Austria
30th 2012* Granada Spain Combined with 7th ICAE
31th 2014* Dresden Germany
32nd 2016* Prague Czech Republic

* proceedings published

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