垫衬补偿对含翘曲间隙L型层合板力学性能的影响研究

Effect of shimming on mechanical properties of L-shaped laminates with warped gap

复合材料结构整体化制造中极易产生由固化变形引起的局部翘曲,该翘曲会显著削弱螺栓装配下复合材料结构的承载能力。通过试验和数值分析开展了垫衬补偿对含翘曲间隙L型层合板极限载荷恢复效率以及失效行为的影响研究。通过微观CT表征了含翘曲间隙L型层合板在螺栓装配后的损伤分布特征,并测试了其极限承载能力;对比分析了垫衬补偿对螺栓装配后含翘曲间隙L型层合板损伤和极限承载能力的影响;并借助数值分析手段定量地研究垫衬补偿对含翘曲间隙L型层合板承载能力恢复的影响机制。结果表明:紧固强制消除翘曲间隙会在螺栓装配区域和拐角处出现一定程度的分层损伤,其中拐角区域的分层损伤可能是促使加载过程分层快速扩展,并导致极限承载能力大幅下降的主要原因;垫衬补偿技术极大的减小了装配损伤的出现,尤其是避免了拐角区域分层损伤的快速扩展,有效提高含翘曲间隙复合材料结构的极限承载能力。

Curing deformation induced local warping is easy to be found during the integrated manufacturing of composite structures.This warping significantly weakens the bearing capacity of the composite structure with bolted assembly.In this paper,the effect of shimming on the ultimate load recovery efficiency and failure behavior of L-shaped laminates with warpage gaps was studied experimentally and numerically.First,the damage distribution of L-shaped laminates with warpage gaps after bolt assembly was characterized by micro-CT,and the ultimate bearing capacity of L-shaped laminates was tested.Then,the influence of shimming on the damage and ultimate bearing capacity of L-shaped laminates with warpage gaps after bolt assembly was analyzed.The influence mechanism of shimming on bearing capacity recovery of L-shaped laminates with warpage gaps was quantitatively studied by numerical analysis.It is found that the forced closing of warpage gap by fastening causes delamination damage to a certain extent in bolt assembly area and corner area.The delamination damage in the corner area may be the main cause of the rapid extension of delamination in the loading process and the significant decrease of ultimate bearing capacity;the shimming technology greatly reduces the assembly damage,especially avoids the rapid expansion of the layered damage in the corner area,and effectively improves the ultimate bearing capacity of the composite structure with warpage gap.