Abstract

In this article, the tensile fatigue properties of 3D orthogonal woven composites (3DOWCs) and biaxial warp knitted composites in 0°, 30°, 45°and 90° directions were studied and compared experimentally. The quasi-static tensile test and tension–tension fatigue test were carried out to obtain the stress–strain curves, the S–N curves and stiffness degradation curves. The results indicate that the two types of composites both exhibit greater stress in 0° and 90° directions and greater strain in 30° and 45° directions. The S–N curves obtained by experimental fitting can better reflect the fatigue degree of the two composites. The stiffness degradation rate of 3DOWCs is much higher than that of biaxial warp-knitted composites except in the 90° direction. The aim of this study is to provide a theoretical study for two kinds of composites to ensure the longest service life in practical applications.

摘要

本文对3D正交编织复合材料（3DOWCs）和双轴经编复合材料在0°、30°、45°和90°方向的拉伸疲劳性能进行了实验研究和比较。进行准静态拉伸试验和拉伸-拉伸疲劳试验，得到应力-应变曲线、S-N曲线和刚度退化曲线。结果表明，两种复合材料在0°和90°方向均表现出较大的应力，在30°和45°方向上均表现出较大的应变。通过实验拟合得到的 S-N 曲线可以更好地反映两种复合材料的疲劳程度。除 90° 方向外，3DOWCs 的刚度退化率远高于双轴经编复合材料。