Site: University of Tokyo
7-3-1 Hongo
Bunkyo-ku 113, Japan

Date Visited: December 7, 1992

Report Author: F. Xavier Spiegel

ATTENDEES

JTEC:

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

HOSTS:

Dr. Isao Kimpara

Professor, Dept. of Naval Architecture and Ocean Engineering

Mato Heder, M.Sc., Ph.D.

Dept. of Naval Architecture and Ocean Engineering

BACKGROUND

The Kimpara-Kageyama Laboratory in the Department of Naval Architecture and Ocean Engineering is concerned primarily with the characterization of the mechanical properties of graphite and Kevlar composites. Their testing is performed on coupons supplied by industry; they do little fabrication of their own.

Non-destructive evaluation is emphasized. Delamination is studied using C-scan and acoustic emission. Vibration pattern images are also used for damage evaluation, and some fatigue testing is conducted.

Dr. Kimpara believes the trends in composites are identical in Japan and the United States. He sees future new applications in civil engineering (especially concrete structure repair), and in transportation, if costs can be reduced. In manufacturing technology Dr. Kimpara considers production improvements are needed in resin transfer molding, vacuum bag molding, and room temperature curing. He considers Aramid fiber use other than in the aerospace industry to be crucial. The main problems in naval use of composites lie in the damage tolerance of composites to impact.

Dr. Kimpara noted the difference in the educational systems of Japan and the U.S., mentioning that the universities of Japan are quite independent. Coordination is not unified. Their funding is from the Ministry of Education, not MITI.

The visit concluded with a brief tour of the Kimpara-Kageyama Laboratory where the JTEC team met Dr. Mato Heder. The equipment was typical of a small university laboratory -- modest but adequate. The research at this facility is primarily in the area of mechanical testing.

REFERENCES

Chang, W.T., I. Kimpara, K. Kageyama, and I. Ohsawa. 1990. "New Data Reduction Schemes for the DCB and ENF Tests of Fracture-Resistant Composites." Developments in the Science and Technology of Composite Materials. Proc. ECCM-4, September 25-28, 1990, Stuttgart- F.R.G.

Kageyama, K., and Kimpara, I., 1991, "Delamination Failures in Polymer Composites." Materials Science and Engineering, A143.

Kageyama, K., I. Kimpara, T. Suzuki, I. Ohsawa, and S. Kabashima. 1990. " Mode II Interlaminar Fracture Toughness Under Impact Loading." "Benibana" International Symposium on how to Improve the Toughness of Polymers and Composites, Yamagata, Japan (October 8-11, 1990).

Kimpara, I., K. Kageyama, E. Tsushima, J. Takayasu, and K. Inoue. 1990. "On the Micromechanical Failure Process of Single Carbon Fiber and Strand in a Matrix." Achievement in Composites in Japan and the United States. A. Kobayashi, Ed., Proc. Japan-U.S. CCM-V, Tokyo.

Kimpara I., and T. Ozaki. 1988. "Study on Reliability Assessment System of Composite Materials." J.S.N.A. Japan, Vol. 158, Dec. 1985, Vol. 159, June 1986, Vol. 161, June 1987, and Vol. 163, June 1988.

Kimpara, I. "Mechanics and Design of Composite Materials and Structures."Theoretical and Applied Mechanics 37.

Kimpara, I., I. Ohsawa, M. Kawashima, T. Horikawa, and T. Mori. 1986. "Characterization of Crack Resistance Performance of Continuous Glassfiber Reinforced Polyurethane Foam by Acoustic Emission." Progress in Acoustic Emission III. The Japanese Society of NDI.

Kimpara, I., Kageyama, T. Suzuki, and I. Ohsawa. 1992. "Acoustic Emission Monitoring of Damage Progression of CFRP Laminates under Repeated Tensile Loading". Progress in Acoustic Emission VI. The Japanese Society for NDI.

Kimpara, I. 1989. "Effect of Interfacial Strength on Tensile Behavior of Unidirectional Pitch Based Carbon Fiber Composite." 21st International SAMPE Technical Conference (September 25-28, 1989).

Kimpara, I., K. Kageyama, T. Suzuki, and I. Ohsawa. 1991. "Fatigue and Impact Strength of Aramid/Glass Hybrid Laminates for Marine Use." In Proceedings of the 8th International Conference on Composite Materials (ICCM/8) (Honolulu, July 15-19, 1991).

Kimpara, I. 1991. "Use of Advanced Composite Materials in Marine Vehicles." Marine Structures 4.

Kimpara, I., and Tsuji, N., 1988, "Failure Process and Strength of CFRP Structural Joints." In Proceedings of the Fourth Japan-U.S. Conference on Composite Materials (June 27-29, 1988).

Ohsawa, I., I. Kimpara, K. Kageyama, and T. Suzuki. 1992. "Acoustical Analysis of Transverse Lamina Cracking in CFRP Laminates Under Tensile Loading." In Proceedings of the 4th International Symposium on Acoustic Emission From Composite Materials (AECM-4) (Seattle, July 27- 31, 1992). ASNT, Inc.

Outline of Kimpara-Kageyama Lab. NAOE CoMET. Kimpara-Kageyama Lab. Department of Naval Architecture and Ocean Engineering, Faculty of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkkyo-ku, Tokyo, 113, Japan. Ozaki, T., and M. Okumura, M., 1991, "Nondestructive Evaluation of Composites by Elastic Wave Propagation Analysis." In Proceedings of the 8th International Conference on Composite Materials (ICCM/8) (Honolulu, July 15-19, 1991).

Sun, F., I. Kimpara, K. Kageyama, T. Suzuki, and I. Ohsawa. 1991. "Failure Modes and AE Characteristics of Carbon Fabric Composites." In Proceedings of the 8th International Conference on Composite Materials (ICCM/8) (Honolulu, July 15-19, 1991).


Published: April 1994; WTEC Hyper-Librarian