Paper number 366

CRACK PROPAGATION PROPERTIES OF GFRP LAMINATES UNDER ACID STRESS ENVIRONMENT

Kazuhiro Onodera¹ , Masaru Mizuno¹ and Hiroyuki Kawada²

1Graduate School of Waseda University
3-4-1, Ohkubo, Shinjuku, Tokyo, 169-8555, Japan
2Department of Mechanical Engineering, Waseda University
3-4-1, Ohkubo, Shinjuku, Tokyo, 169-8555, Japan

Summary

The purpose of this study is to clarify crack propagation properties of woven GFRP laminates under stress corrosion cracking (SCC) conditions. The crack propagation behaviors and the threshold stress intensity factors KISCC for the stress corrosion cracking are determined by the constant loading tests and the cyclic loading tests. In the cyclic loading tests, it is possible to exclude effects of the frequency and the stress ratio on crack propagation behaviors in the KImax-da/dt diagram under the environmental condition(1mol/l, 303K), and it is suggested that the crack propagation behavior depends on KImax and time. As for an acid concentration, there is a conspicuous difference in crack propagation between the cyclic and the constant loading conditions. For any concentration of the acid, the cyclic crack-propagation rate is slower than the constant one under the solution temperature of 303K. Based on fractographic observations, it is found that micro-mechanisms of the crack propagation of both loading conditions are different, and fiber-matrix interfacial debondings are remarkable under the cyclic loading condition.

Keywords

GFRP laminates, stress corrosion cracking, stress intensity factor, threshold, stress ratio, frequency and environmental condition.