Off-Axis Creep of Unidirectional Polymer Matrix Composites Subjected to Step Changes in Stress at Elevated Temperature

摘要

To understand properties of polymer matrix composites and to correctly evaluate their performance and reliability under service stress conditions at elevated temperatures, it is one of the most important issues to elucidate by experiment their time- and rate-dependent nonlinear behavior and their history dependence. The present study aims to examine a short-term creep behavior of unidirectional carbon fiber-reinforced polymeric composite under off-axis constant and variable stress conditions at elevated temperature. First, stress-dependence and directional nature of the off-axis tensile creep behavior are elucidated from constant-stress creep tests. Then, creep responses of off-axis specimens subjected to either the stepped increase or a stepped decrease in stress are observed to manifest characteristics of a matrix-dominated creep hardening of composite. Off-axis creep recovery after completely removing the creep stress for each of the tensile creep tests is also observed.