缝合复合材料的细观力学分析

采用三维细观有限元模型,研究了缝合复合材料的力学性能.模型中引入了保证单胞边界面的应力和位移周期连续的边界条件,分析了缝合对层合板面内力学性能的影响,着重考察了缝合区域内细观应力和应变的分布,以及缝合对材料弹性常数的影响,并分析了缝线附近和富树脂区应力集中的规律.算例结果表明本文方法可以有效地预测缝合复合材料的弹性性能.研究还发现,受面内剪切作用时原来单胞的平面边界不再保持平面,各层间铺设角度相差越大,单向拉伸时应力集中现象越显著.

Meso-Mechanical Analysis of Stitching Laminated Composites

The mechanical properties of stitching laminated composites are analyzed by using 3D micro FEM model.In the 3D micro cell model,unified boundary conditions are constructed to guarantee the continuity of local displacements and stresses on cell boundaries.The effect of stitching on the in-plane elastic constants of stitched laminates is discussed.Study is focused on the distributions of local stresses and strains in the stitching zone.The effect of micro non-homogeneity on global mechanical constants of the material is evaluated.The rule of stress concentration around the stitching yarn and rich resin region is also analyzed.Numerical results indicate that the method presented herein can used to predicate elastic properties of stitched laminates effectively.It is also found that the cell's previous plane boundaries no longer remain a plane under the in-plane shear loading.The larger the difference of layer angles,the severer the stress concentration of stitched laminates under uni-axial tensile loadings.