1999 journal article

The effect of thermal aging on the Mode-I interlaminar fracture behavior of a high-temperature IM7/LaRC-RP46 composite

COMPOSITES SCIENCE AND TECHNOLOGY, 59(8), 1271–1286.

co-author countries: United States of America 🇺🇸
Source: Web Of Science
Added: August 6, 2018

High-temperature Mode-I interlaminar fracture tests have been conducted to evaluate the effect of thermal aging at various temperatures on the fracture behavior of IM7/LaRC-RP46 composites. Double cantilever beam specimens made of unidirectional laminates were used in the test program. The specimens were aged at high temperatures for times up to and including 6000 h. Changes in fracture behavior that occurred over periods of aging time and aging temperature have been measured and determined for variations of test temperature and loading rate. As expected, the crack growth at high temperature showed non-linear load–displacement response as a result of the rate-dependent nature of behaviour of the matrix. Present loading rates had no measurable effect on GIC values for unaged and aged specimens. High temperature increased GIC values of aged and unaged specimens at temperature near Tg and decreased at temperatures above Tg. Thermal aging for longer times also significantly reduced GIC initiation values for aged specimens. In contrast, thermal aging increased GIC propagation values as a result of the occurrence of increased fiber bridging, fiber breakage and microcracks, as deduced from SEM studies. Results also indicated that high temperatures slowed crack-growth rates. However, thermal aging and higher loading rates accelerated crack-growth rates. The effect of thermal aging and temperature on the crack growth rate, da/dt, can be correlated with the C* parameter in the power-law relationship.