开孔变刚度层合板压缩屈曲性能研究

针对开孔变刚度层合板,建立3种尺寸的层合板有限元模型,采用了线性屈曲、引入残余热应力的线性屈曲和引入初始缺陷的非线性屈曲的3种分析方法,研究了开孔层合板在压缩条件下的屈曲行为,并通过自动铺丝制造层合板进行试验对比,对3种方法的合理性进行了分析。结果表明,引入残余热应力的线性屈曲分析方法与试验结果最吻合,两者仅相差0.63%。基于该方法,讨论开孔层合板残余热应力分布特点和应力水平,得出了开孔层合板的应力分布云图和应力分布规律,计算出残余热应力对开孔复合材料层合的屈曲影响。结果表明,残余热应力对传统直线开孔层合板的屈曲载荷影响很小,仅提高了3.57%,但大大提高了变刚度开孔层合板的屈曲载荷,最多可达23.40%。说明纤维曲线铺放可以改变内部残余热应力的分布,提高整个开孔层合板承载压缩载荷的能力。

Buckling Analysis of Variable Stiffness Composite Panels with Holes Under Compression

For the study of the buckling behavior of the variable-angle-laminated composite plate under compression loading, three buckling analysis methods are carried out to model the variable-angle-laminated composite plate with holes: linear buckling analysis, linear buckling analysis with residual thermal stresses and non-linear buckling analysis with initial imperfections. Then experiments are conducted to verify the rationality of the three methods. It is shown that linear buckling analysis method with residual thermal stresses agrees well with the experimental results, which only differs by 0.63%. With this method, the residual thermal stress distribution characteristics and stress level are discussed to find the stress distribution nephogram and the stress distribution law. And then the influence of residual thermal stress on the buckling behavior of the variable-angle-laminated composite plate is calculated. The results show that the residual thermal stress has little influence on the buckling behavior of the straight fiber laminate only with a 3.57% increase, while the buckling behavior of the variable-angle-laminated composite plate improves significantly, which increases up to 23.40%. It is shown that curvilinear fiber can change the distribution of residual thermal stress, which reduces the combined resultant stress near the center of the composite plate with holes, so the critical buckling load of the laminate with hole increases.