缝合泡沫夹芯复合材料低速冲击的多尺度数值方法

Multi-scale simulation of stitched foam-core sandwich composites subjected to low-velocity impact

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。

Multi-scale approach has been developed for evaluating the damage resistance of sandwich structures composed of stitched foam-core and woven face sheets subjected to low-velocity impact. Simplified model of stitched foam-core was established. The classical theory of homogenization was adapted and used by treating the foam strengthened by the glass fiber resin column as orthotropic equivalent core material which elastic properties depended on each component and their volume participation. And finite element model of sandwich structure was established. Interface elements were added between panels and foam-core to simulate the initiation and propagation of adhesive disbond damage. Impact behaviors of the stitched foam-core sandwich composites were calculated with GENOA progressive failure analysis commercial software and compared with those in experimental. Good agreements between numerical and experimental were found, which demonstrates the validity of the multi- scale progressive failure analysis method. The analysis shows that the damage in upper panel and delamination between panels and foam-core reduce effectively when the sandwich composites stitched. However, stitches brought initial damage to the structure; higher stitch density increased the foam core stiffness, as a result, reduced energy absorption capability of sandwich structures.