泡沫夹芯复合材料梁界面裂纹曲折扩展实验与数值模拟

Experimental investigation and numerical simulation of interfacial crack kinking in foam core composite sandwich beams

采用双悬臂梁(DCB)试验研究了具有不同密度的PMI泡沫芯体的玻璃纤维增强复合材料夹芯梁界面裂纹曲折破坏路径。基于包含裂纹的物质点算法(MPM),建立了与试验研究相适应的MPM模型,在不同的面板/芯体模量比下计算了界面裂纹裂尖模态比和曲折破坏角,并结合曲折破坏准则模拟了界面裂纹曲折破坏路径。数值模拟结果和试验现象吻合良好,说明了本文中数值分析模型和方法的有效性。研究结果表明,面板材料和芯体材料模量失配越严重,界面裂纹发生曲折破坏时的破坏角越大;裂纹折入芯体后,在Ⅰ型为主的加载模式的支配下以基本平行于界面的方向扩展。

The interracial crack kinking paths in glass fiber reinforced composite sandwich beams were experimentally investigated with double cantilever beam （DCB） specimens, and a series of polymethacrylimid （PMI） foam core with different densities was considered. According to the specimens numerical models were built by material point method（MPM）. Mode mixity and kinking angle were calculated with different facing-to-core modulus ratio, and crack kinking paths were simulated. A good accordance was found between numerical results and experimental observations which demonstrates that the MPM algorithm and numerical model presented in this paper is efficiency and accuracy. The result indicates that if kinking occurs bigger kinking angle will be obtained with stronger facing-to-core modulus mismatch, and after kinking into the core the crack will propagate parallel to the face/core interface because the loading becomes highly mode I dominated.