复合材料开缝柱壳压缩屈曲分析与试验

Analysis and experiments of composite cracked cylindrical shell under axial compression

通过试验测量了复合材料开缝柱壳在轴压作用下的屈曲性能,得到其发生屈曲的临界载荷和后屈曲之后的破坏载荷。建立了开缝柱壳的有限元模型,利用Hashin失效准则和特征值法分别进行静强度分析和线性屈曲分析。将有限元一阶屈曲载荷与试验屈曲载荷和静强度破坏载荷对比,有限元结果和试验结果吻合较好。试验表明,开缝柱壳在加载过程中经历了线弹性压缩、线性屈曲、后屈曲3个阶段,最终结构发生屈曲破坏。开缝周围最先发生变形,整个结构屈曲变形较复杂。结构在线性屈曲以后仍能继续承载,发生了后屈曲。研究结果表明,保持缝的长度不变,屈曲载荷随缝的宽度的增加而减小,保持缝的长和宽不变,柱壳长度改变对结构刚度几乎没有影响,增大45°铺层角度也会降低开缝柱壳的屈曲载荷。

Buckle behavior of integral composite cylindrical shell structure is studied by experiments. The critical load and the failure load of buckling are both obtained. An FEM model of the cracked cylindrical shell is then established. Hashin failure rule and eigenvalue method are applied in order to analyze the static strength and buckle property of the structure. Compared the FEM first order buckling load to the experimental buckling load and static strength failure load, the result of the FEM model shows good correlation with the experiment. Experimental results have shown that the cracked cylindrical shell structure experienced linear elastic, linear buckling, post- buckling stages before buckling failure. The structure around the crack buckle vary first. The buckling of the structure is complex and the structure can still bearing the load after post-buckling. Parameter studies shows that buckling load increases with the crack width decreases while keep the crack length unchanged. Meanwhile, buckling load increases with the length of the cylindrical shell increases and it will also decrease if changing the angle of 45° plies.