纤维增强复合材料薄壁圆管扭转失效分析
Failure analysis of fiber reinforced composite thin-walled circular tubes under torsion load

对碳纤维增强树脂基复合材料（CFRP）薄壁圆管的扭转屈曲、失效载荷和失效模式进行了试验和数值模拟。试验观察圆管在扭矩作用下的3种失效模式，分析了不同失效模式的特征和机理。考虑圆柱壳的初始缺陷和非线性屈曲等因素，利用ABAQUS建立了圆管屈曲和损伤的有限元模型。结果表明：屈曲诱发圆管表面微裂纹的产生和扩展，对圆管的失效有着加速作用；扭转失效过程中圆管层间应力较低，层间分层主要由管壁突然的破坏产生；圆柱壳的初始缺陷对屈曲和失效载荷的模拟影响较大，本文通过对比计算结果和试验数据确定了圆管的初始缺陷系数；损伤模型的数值模拟结果与试验数据相一致，验证了有限元模型的有效性。 The torsion buckling, failure load and failure modes of the carbon fiber reinforced polymer (CFRP) thin-walled circular tubes were tested and numerical simulated. Three failure modes of the circular tubes under torque were observed in the test, and the characteristics and mechanism of different failure modes were analyzed. Buckling and damage finite element models of the circular tubes were established by ABAQUS considering the factors such as initial imperfection and nonlinear buckling etc. of cylindrical shells. The results show that buckling could induce micro crack produce and propagation on the surface of the circular tubes, and it accelerates failure of the circular tubes. The interlaminar stress of the circular tubes under torque failure process is relatively small, and the interlaminar delamination is mainly caused by the sudden damage of the tube wall. The initial imperfection of the cylindrical shells has a great influence on the buckling and failure loads. The initial imperfection coefficient of the circular tube was determined by comparing the calculation results with test data in this paper, and the numerical simulation results of damage models and test data are consistent, which verifies the effectiveness of the finite element models. 航空科学基金（2015ZA51010）