粘弹性基体复合材料层合板的固化残余应力和曲率变化

VARIATION OF CURE RESIDUAL STRESS AND CURVATURE OF RESIN MATRIX COMPOSITE LAMINATES

粘弹性基体复合材料层合板因铺层取向差异而产生的固化残余应力会随层合板在室温下放置时间的推移而变化 ,这一过程可通过非对称层合板的曲率变化得到反映。本研究通过非对称板的曲率变化实验来观察板内残余应力的变化过程 ,并根据细观复合材料力学理论和适宜的变形分析方法建立一种与残余应力最终稳定分布相对应的铺层修正折减模量矩阵 ,用于进行层合板固化残余应力和曲率变化的渐近值预测 ,并依此确定固化后残余应力的变化范围。

Residual stress in viscoelastic resin matrix composite laminates at room temperature can keep varying during a long period of time. The characteristic can be reflected by the curvature variation of unsymmetrical laminates. A curvature variation test of unsymmetrical laminate was conducted and the test results indicate that the curvature and residual stress can finally tend to a stable state. Based on the test results, a revised ply stiffness matrix corresponding to the final stable state is deduced by means of a micromechanics model and the calculation method appropriate for the large deformation of composite laminates. The revised stiffness matrix can be used to predict the final stable state of the residual stress and deformation of composite laminates with different stacking sequences, and then determine the variation scope of residual stress. Tests of different laminates for verifying the effect of revised stiffness matrix were also conducted and the test results quite agree with the prediction.