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在试验研究的基础上,建立三维损伤累积模型研究拉伸载荷下挖补修理复合材料层合板的损伤扩展及其最终破坏规律,并讨论挖补角对挖补修理结构拉伸性能的影响,计算结果和试验结果吻合良好。研究结果表明:挖补胶层中的损伤首先发生在胶层连接0°铺层的地方,然后向四周扩展,当损伤扩展到整个胶层面积约40%时,挖补层合板的应力-位移曲线发生较大的刚度下降,此时的载荷为胶层失效载荷。母板和补片在胶层发生损伤前就出现了少量损伤,在胶层完全破坏前,损伤会沿胶界面扩展;在胶层完全破坏后,损伤会沿母板最窄处向两侧自由边快速扩展,而补片在胶层失效后就停止损伤;胶层失效载荷随挖补角的增大而减小,但挖补角的增大会使胶层破坏后母板的承载能力增加,从而使挖补层合板的最终破坏载荷反而增加。在工程应用中,挖补角的选择应综合考虑结构设计要求、工艺和功能等多方面的因素。
Based on the experimental study, a three-dimensional cumulative damage model is established to study the damage propagation and ultimate failure of composite laminates under tension load. The effect of digging angle on the tensile properties of digging and repairing structures is discussed. The calculation results and experimental results The result is in good agreement. The results show that the damage in the dredging layer firstly occurs when the layer is connected with 0 ° ply and then extends all around. When the damage extends to about 40% of the area of the layer, the stress-displacement curve of the dredging layer occurs The greater the stiffness decreases, the load at this time is the layer failure load. Motherboard and patch in the plastic layer damage occurred before a small amount of damage in the complete destruction of the plastic layer before the damage will spread along the plastic interface; in the complete destruction of the plastic layer, the damage along the motherboard will be the narrowest at both sides of the freedom While the patch stops damaging after the adhesive layer fails. The failure load of the adhesive layer decreases with the increase of the digging angle, but the increase of the digging angle will increase the carrying capacity of the motherboard after the adhesive layer is damaged, The ultimate failure load of the laminate increases instead. In engineering applications, the choice of digging angle should take into account the structural design requirements, process and function and other factors.