纤维增强复合材料层合板缺口尺寸及形状效应数值模拟

通过考虑基体裂纹、纤维断裂、层内劈裂和层间脱层等破坏形式,建立三维有限元模型研究含中心圆孔和中心裂缝的准各向同性复合材料层合板([45/0/-45/90]_(2S))在拉伸载荷下的缺口尺寸效应及缺口形状效应。模拟结果显示:随着缺口尺寸的增大,层合板的破坏强度逐渐降低,然而,在本文研究范围内含中心裂缝的层合板破坏强度始终高于对应的含中心圆孔的层合板破坏强度。进一步分析有限元模拟结果表明,含中心裂缝的层合板亚临界损伤发生得更早,并且亚临界损伤范围更大,亚临界损伤会大大缓解缺口尖端的应力集中,从而使含中心裂缝层合板表现出更高的破坏强度。

Numerical simulation on notch size and shape effects of fiber-reinforced composite laminates

A 3D finite element model was developed in this work by considering damage modes like matrix cracking,fiber breakage,intra-ply splitting and inter-ply delamination.The notch size effect and notch shape effect of tensile quasi-isotropic composite laminates ([45/0/-45/90]2S) with central holes and central cracks were studied by the finite element model.The simulation results indicate that the damage strength of the laminates decreases with the increasing of notch size.However,the laminates with central cracks always show higher damage strengths than those with corresponding central holes for the laminates studied in this paper.A further investigation of the finite element simulation results shows that subcritical damage forms earlier in cracked laminates with larger subcritical damage zones.The subcritical damage will significantly alleviate the stress concentration at the notch tip,and therefore make the cracked laminates exhibit higher damage strengths.