As expected, experts from both nations exchanged information on various aspects of this technology.
Symposium organizers E. Rokhlin from Iowa State University and Prof. Kishi from the University of Tokyo successfully presented an excellent program on the newest NDT methods.
About 140 participants from the US and Japan attended over 50 sessions during the four day conference. Points emphasized varied according to the organizer of the particular session. For instance, "Non-Contact-Ultrasonic," "Infrastructure," or use of NDT in transport monitoring.
Another theme was the long-life inspection of equipment and structures, especially for airplanes, bridges and nuclear power stations. The use of modeling methods was pointed out as being an important tool for investigating new applications, especially for the first steps in material characterization with laser ultrasound. A contribution from Japan presented a detailed analysis of ultrasound signals for getting information about crack characteristics.
The second day session was opened by Mr. Yamanaka from Mechanical Engineering Laboratory (Tsukuba City, Japan). He introduced a new electromagnetic high frequency transducer up to 250 MHz used for resonance thickness measurement of thin layers. He also introduced a new finite difference modeling method for sound propagation in austenitic materials, and showed results similar to those obtained by the EFIT program from GHT Kassel Germany.
The reporter was surprised by the introduction of an angle controlled ultrasound generation, which operates by principles of a small phase shift between two laser sources.
Contributions about the eddy current method focused on corrosion testing for airplanes as well as for radioactive waste containers.
The third day contributions concentrated on testing problems of advanced materials. For example, diamond surfaces on silicon disks, and porous ceramic for heat exchangers used in power stations, or Metal-Matrix Composites (e.g. Silicon carbide fiber in Titan). Ultrasonic testing and microscopy dominated the scene, with emphasis on bonding characterization between the fibers and the matrix.
The last two days focused generally on early stage damage detection applied to highly stressed components, (e.g., temperature resistant turbine disks, ceramic surfaces).
The poster session showed some well known applications such as NDT for ceramics with high resolution equipment. It was interesting to find here the use of relative low frequencies (15, 20, 25 MHz) and broadband transducers, as well as composite transducers, however the Japanese display didn't meet the high resolution of the American site.
The radiography method was mentioned less at the symposium, although there were presentations dealing with image quality with neutron radiography and high energy X-Ray Radiography with linear accelerators. A very interesting contribution introduced the X-Ray Back Scattering method, for instant investigation of certain layers of composite material (impact problems). There is a potential for using this method for detection of impact defects; this could be an alternative to the traditionally used UT method.
In informal conversation, the Japan colleagues mentioned their interest in holding a similar bilateral German-Japanese conference. The first one could be held in Germany, possibly in 1998.
BAM Berlin - NDT Department VIII.4
The Federal institute of Materials Research and Testing (BAM) is a scientific-technological institute under the authority of the Federal Minister of Economics. In accordance with a decree of the Federal Minister of Economics dates September 1, 1964, BAM promotes the development of German industry by carrying out research on materials and by further developing testing techniques and chemical safety engineering. The institute collects and makes the results of its own and others scientific work available to the general public in suitable form.
Rolf Diederichs 01. Oct 1996, firstname.lastname@example.org