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为了发展缝合泡沫夹芯复合材料低速冲击损伤的多尺度分析方法,建立了缝合泡沫简化力学模型,将缝合泡沫等效为缝线树脂柱增强的正交各向异性芯材,其材料参数由各组分性能及所占体积分数根据均一化理论计算得出;同时,建立冲击试验有限元模型,通过界面元模拟面板与芯材之间的层间分层。采用GENOA渐进损伤分析模块对缝合结构冲击动态响应过程进行数值模拟,并将计算结果与试验记录进行对比分析。结果表明:缝合可以减小面板破坏面积,抑制面板与泡沫分层的扩展;但缝纫会对结构造成初始损伤,较高的缝合密度使芯材刚度增加,不利于泡沫结构的缓冲吸能。数值模拟结果与试验记录吻合良好,验证了多尺度分析方法的正确性。
In order to develop a multi-scale analysis method of low velocity impact damage of stitched foam sandwich composite, a simplified mechanical model of stitched foam was established. The stitched foam was equivalent to an orthogonal anisotropic core material reinforced by suture resin column. The properties and the volume fraction of the components were calculated according to the theory of homogenization. At the same time, the finite element model of impact test was established, and the interlayer delamination between the panel and the core material was simulated by the interface element. The GENOA progressive damage analysis module was used to simulate the dynamic response of the suture structure. The calculated results were compared with the experimental records. The results show that the suture can reduce the area of the panel failure and restrain the delamination of the panel and the foam layer. However, the sewing will cause initial damage to the structure, and the higher stitching density will increase the stiffness of the core material, which is unfavorable to the cushioning energy absorption of the foam structure. The numerical simulation results are in good agreement with the experimental records, verifying the correctness of the multi-scale analysis method.