基于结构参数的平纹机织复合材料等效弹性性能预测

Prediction of the effective elastic properties for plain woven fabric composite based on the structural parameters

经向纤维束与纬向纤维束纵横交错引起的纤维弯曲(也称为波纹)是平纹机织复合材料固有特征。首先,提出了一种精确描述平纹机织复合材料单胞3D结构特征的数学表达式。其次,基于经典层合板理论和等应力假设,考虑平纹机织复合材料厚度方向非对称引起的弯曲-拉伸耦合效应及单胞结构特征,建立了含结构参数的平纹机织复合材料等效弹性性能多参数解析模型。通过数个典型算例验证了建立的多参数解析模型,结果表明:该多参数解析模型预测值与相关文献中有限元模型预测值、解析模型预测值、实验值等均吻合较好;该多参数解析模型预测值尤其是Z向弹性性能预测值,比文献中解析模型预测值更接近于实验值。在此基础上,进一步探讨了纤维束波纹比(包括纤维束波动方向波纹比与纤维束横截面波纹比)、经向与纬向纤维束构成的预成形体厚度、纤维束中弯曲部分的长度、相邻纤维束之间间距等结构参数对平纹机织复合材料弹性性能影响。该多参数解析模型建模方法为研究纺织复合材料力学性能提供了参考。

The warp and fill fiber strands interlacing in two mutually orthogonal directions to one another results in the fiber curvature,namely the waviness,which is the inherent characteristic of plain woven fabric composite.First,a mathematical description was developed to accurately represent the 3D architecture morphology of the unit cell for plain woven fabric composite.Next,an analytical multi-parameter model of plain woven fabric composite was established based on the classical lamination theory and iso-stress assumption.Meanwhile,the bending-extension coupling effect due to asymmetry along the thickness-direction as well as the architecture morphology of the unit cell was embedded in this model.The validation of several typical cases shows that the predicted effective elastic properties of plain woven fabric composite agree well with the numerical values of the finite element model,the results of the analytical model and the experimental data cited in the related literatures.Also,the predictions of the analytical multi-parameter model,especially the Z-direction ones,are more approaching to the experimental data than counterparts of other analytical models aforementioned.Furthermore,the influence of the structural parameters such as the waviness ratio of the fiber strand containing both the undulation direction and the cross section,the thickness of the preform consisting of the warp and fill fiber strands,the length of the curved section of the fiber strand and the spacing between the adjacent fiber strands on the elastic properties of plain woven fabric composite is elaborated.The present approach of the analytical multi-parameter model provides a reference for evaluating the mechanical properties of textile composite.