金属-机织复合材料混合结构的三点弯曲力学性能及失效机理EI北大核心CSCD

为解决传统金属与复合材料混合成形方法中存在的分层失效、纤维破坏等问题,设计一种结合金属增材制造、复合材料机织与缝合等工艺的新型混合结构,将金属骨架与机织复合材料法向缝合后共固化成形,增加异质材料之间的结合强度,实现宏观尺度上金属与复合材料的灵活成形与稳定连接。通过三点弯曲实验研究新型混合结构的面内弯曲性能,采用非接触式图像测量手段分析混合结构样件的损伤形貌及失效机理。结果表明:混合结构失效是多种失效模式的组合,包括纤维层上侧压缩/下侧拉伸断裂、异质材料层间失效及金属塑性损伤等;层间分层是由界面旁侧存在基体裂纹和层间剪应力、相邻层间刚度不相容等多因素造成的;随着样件结构厚度增加,其结构弯曲强度和弯曲弹性模量均增大;开孔处引入缝合纤维可以在一定程度上抑制分层裂纹的扩展,提高结构抗分层断裂性能。

Mechanical properties and failure mechanisms of metal-woven composite hybrid structures under three-point bending

In order to solve the problems of delamination failure and fiber destruction in the traditional metal-composite hybrid forming method, a new hybrid structure combining metal additive manufacturing, composite weaving and stitching processes was designed. The metal skeleton and woven composite materials were co-cured and formed after completing normal stitching, which increased the bonding strength among heterogeneous materials. Flexible forming and stable connection between metal and composite materials on macroscopic scale were also realized. The in-plane bending performance of the new hybrid structure was investigated by a three-point bending test. The damage morphology of the sample parts and their failure mechanisms were analyzed by non-contact image measurement. The results show that: hybrid structural failure is a combination of multiple failure modes, including compression fracture on the upper side of the fiber layer and tensile fracture on the lower side of the fiber layer, interlaminar failure of heterogeneous materials and plastic damage of metals; the interlaminar delamination is caused by the presence of matrix cracks and interlaminar shear stresses next to the interface, as well as incompatible stiffnesses between adjacent layers; the structural bending strength and bending modulus of elasticity of the samples increase with the increasing structural thickness in the experimental range; the stitching fibers introduced at the openings can inhibit the expansion of delamination cracks to a certain extent and improve the structural resistance to delamination.