缝纫复合材料层合板面内拉伸强度研究

旨在研究由缝纫引起的材料弹性性质的变化并对缝纫复合材料层合板面内拉伸强度进行理论预测。认为缝纫引起的面内纤维偏转是缝纫影响复合材料面内力学性能的主要原因，引入最大纤维偏转角和变形区宽度两个结构参数，提出了描述材料非均匀性的纤维弯曲模型。采用多层次多尺度模拟的方法得到层合板非均匀的材料性质。通过二维有限元分析对单向拉伸载荷作用下的面内强度进行理论预测，得到与试验数据相吻合的结果，进而分析了缝纫密度对拉伸强度的影响。

In-Plane Tensile Strength Analysis of Stitched Composite Laminates

The alteration of the in-plane elastic properties in laminates caused by stitching was modeled and the in-plane effective tensile strength of the stitched composite laminates was predicted. The distortion of in-plane fibers was considered to be the main reason that influences the in-plane mechanical properties. The fiber distortion model was proposed to characterize the fiber misalignment and the fiber content concentration caused by stitching. The inhomogeneous elastic properties of the stitched composite laminates were obtained by using hierarchical multiscale model. By using two-dimensional finite element analysis, the tensile strength of composite laminates was predicted, an acceptable agreement with experimental data was showed, and the effects of stitch density on the in-plane tensile strength were studied.