Site: National Aerospace Laboratory (NAL)
6-13-1 Ohsawa
Mitaka, Tokyo 181, Japan

Date Visited: December 7, 1992

Report Author: F. Xavier Spiegel

ATTENDEES

JTEC:

M. Ashizawa
D. Granville
V. Karbhari
B. Kramer
F. Spiegel

HOSTS:

Dr. Takashi Ishikawa

Section Head, Composite Structure Section,
Airframe Division

Mr. Yasuo Tada

Director, Airframe Division

BACKGROUND

The National Aerospace Laboratories (NAL) has four divisions concerned with composites. NAL is not involved in manufacturing or fabrication but emphasizes testing with three divisions involved with mechanical testing. NAL's total 1991 budget was $85.5 million and they employed 439 people. Its capital investments in test and non-destructive testing (NDT) equipment were very impressive.

Dr. Ishikawa was full of enthusiasm and was quite proud of a CF/thermoplastic wing box model which was fusion bonded; he continued his enthusiasm as he discussed the characterization of CF/polyimide (in support of NASDA's Hope Project), testing machines with environmental chambers (up to 9 m x 5 m x 3 m), high temperature composites of SiC - SiC, tailoring of composites for space with zero coefficient of thermal expansion, a bi-axial testing machine (1 m x 1 m capacity with fully programmable load actuators), impact test systems, a thermal conductivity analyzer, and a mainframe and submainframe testing system. Their NDE efforts include an ultrasonic scanning system (robotic) using pulse-echo and back scatter (10 Mhz to 50 Mhz), thermal imaging, acoustic-emission, x-ray, and CT scanner.

The priority areas of research are chosen by NAL, not the fabricators. There is a thorough understanding of the problems of the fabricators and there are many domestic conferences for interaction. NAL pays for co-operative research and does the testing for all of its fabricators. There is a consistent budget and the manufacturers of the materials are funded for long-term research, typically 10-15 years. They are very patient and understand that failures will occur in research.

The tour of the facility was very impressive. The JTEC team saw many systems including thermal imaging, impact, a large environmental chamber, fracture toughness, ultrasonic imaging enhancement, and the random loading platform. The random loading platform was testing a C/PIX tape wound tubular main spar (see Figure 4 in Ishikawa et al. 1991b).

SUMMARY

Dr. Ishikawa considers manufacturing costs as the main barrier to the use of composites. He anticipates advancements in high temperature resins and thermo- plastics. Research on fibers must be conducted to reduce their cost rather than improve their quality. Improvements must be made in RTM tooling, preforms, and most importantly, resins.

There are many specialty weavers in Japan. NAL rates Toray as the best pre-preg manufacturer, Mitsui the best at high-temperature and tough resins, and Shikibo the best at fabric manufacture. Dr. Ishikawa is not satisfied with the quality of the pre- preg.

The carbon fiber market in Japan has not been significantly impacted by the slowdown in Japan's defense spending.

REFERENCES

Ishikawa, T., Y. Hayashi, M. Matsushima, and T. Noguchi. 1990. "Comparison of Tensile and Compressive Properties of Some Structural Elements Between Carbon/PEEK and Carbon/Epoxy Composites." Reprint from Proceedings of the Fifth Japan-U.S. Conference on Composite Materials, Tama-City, Tokyo (June 24-27, 1990). Held by Japan Society for Composite Materials. 445-452.

Ishikawa, T., Y. Hayashi, H. Fukunaga, M. Matsushima, M., and T. Noguchi. 1991a. "Experimental Examination of Theory of CTE (Coefficient of Thermal Expansion) Control Technology." In JSME International Journal, Series I, 34 (2):178-186.

Ishikawa, T., Y. Hayashi, M. Matsushima, K. Takasawa, and T. Sato. 1991b. "Structural Concept of Main Wings of High Altitude Unmanned Aerial Vehicle and Basic Properties of Thermoplastic Composites as Candidate Material." Reprint from Proceedings of International Pacific Air & Space Technology Conference and 29th Aircraft Symposium Proceedings, Gifu, Japan (October 7-11, 1991). Society of Automotive Engineers, Inc. 677-685.

Ishikawa, T., T. Yamamura, T. Hirokawa, Y. Hayashi, Y. Noguchi, and M. Matsushima. 1992. "Strength Properties of 3D-Woven Si-Ti-C-O (TYRANNO)/SiC High-Temperature Composites for Future Space Transportation." In Proceedings of The Eighteenth International Symposium on Space Technology and Science (Kagoshima). 437- 442.

National Aerospace Laboratory, 1991-1992. "Annual Report". Japan.

National Aerospace Laboratory, Science and Technology Agency. 1992-1993. "Composite Structure Testing Facilities" (brochure). Tokyo.


Published: April 1994; WTEC Hyper-Librarian