结构参数对树脂基纤维编织复合材料折叠夹芯结构力学性能的影响

Influence of Structural Parameters on Mechanical Properties of Resin Matrix Braided Composite Folded Sandwich Structure

折叠夹芯结构是一种新型的复合材料夹芯结构,其结构参数对力学性能有重要的影响。文中以碳纤维和Kevlar平纹编织预浸料为芯材原料,采用热压工艺,制备了复合材料折叠夹芯结构试样。通过压缩试验得到不同条件下折叠夹芯结构在静态压缩载荷作用下的力-位移变化曲线。构建了复合材料折叠夹芯结构有限元模型,对不同结构参数复合材料折叠夹芯的力学性能进行了数值模拟分析,并将模拟结果与实验结果进行对比验证了模型的可靠性。实验及数值模拟的分析结果表明,随着芯材厚度的增加,折叠夹芯层的压缩强度呈线性增加,其破坏形式由假塑性变形逐渐向脆性破坏转化;面板对夹芯层的约束作用能够极大地提高压缩模量和强度,而且上下面板对压缩性能曲线有着不同的影响;折叠夹芯单元的高度、长度、折叠夹角等参数对其力学性能具有不同程度的影响。

As a new type of composite folded sandwich structure, folded sandwich structure has the advantages of light weight, good mechanical properties, easy molding and wide applicability of materials. It has good prospects in the fields of lightweight industrial equipment The structural parameters have very important influence on the mechanical properties, however, there is still little relevant research. In this study, carbon and Kevlar prepreg textile were taken as raw materials of the folded cores. The samples of composite folded sandwich structure was prepared by hot- pressing method. The force-displacement curves of folded sandwich structures under static compressive loading were obtained by compression tests under different conditions. The finite element models of the composite folded sandwich structure were constructed to carry out the numerical simulation and analysis of the mechanical properties of the composite folded sandwich structure with different structural parameters, and the simulation results were compared with the experimental results to verify the reliability of the model. The results show that the compressive strength of the folded core increases linearly with increase of the thickness of the core, and the failure form of the model is transformed from the pseudo-plastic deformation to the brittle failure. The constraint of the panel to the folded core can greatly improve the compression modulus and strength, and the upper and lower panels have different effects on the compression performance curves. The height, length, angle and other parameters of the folded sandwich cell have different effects on its mechanical properties as well.