基体开裂的正交复合材料对称层合板的粘弹性力学行为

本文讨论了含有均匀基体裂纹的正交复合材料对称层合板的线性粘弹性力学行为.采用二维剪切滞后模型并对其层间剪应力在厚度方向进行线性假设分布,求得层合板的平均应力应变的线弹性解,利用等效约束模型和经典层合理论可得到层合板因为含有基体裂纹而所引起的刚度退化现象.在弹性-粘弹性对应原理的基础上对其层合板的线粘弹性进行了讨论和研究.结果表明:层合板的松弛模量和蠕变泊松比随着时间的增加而减少,到达稳态后其值基本上是恒值.并跟Zocher的解析解和有限元数值解作了比较,发现结果非常吻合.

Linear Viscoelastic Behavior of Composite Laminates with Cross-Ply Matrix Cracks

The linear viscoelasicity of cross-ply composite symmetric laminates with matrix cracks loaded in tension and shear stresses was discussed.Matrix cracks were assumed to be spaced uniformly,spanning the whole width of laminate.A two dimensional shear lag analysis where out-of-plane shear stresses in the constraining layers were assumed to vary linearly was used to determine the elastic solution of stresses and strains in a laminate representative segment containing one crack.The equivalent constraint model and classical laminate theory were used to predict the effect of matrix cracking on the in-plane stiffness properties of composite laminates.The linear viscoelasicity of composite symmetric laminates was studied by using elastic-viscoelastic correspondence principle.The result shows that relaxation modulus and creep Poisson's ratio decreas with time.As time approaches infinity the values converge to be constant.The results with Zocher's analytical and FEM solutions agree well.