开口及边界条件对复合材料三分之一柱面壳压缩屈曲性能的影响

研究了完整、开口周边加强及开口加口盖3种型式的复合材料三分之一柱面壳的压缩屈曲性能,考查了3种典型复合材料柱面壳的轴压屈曲强度,分析了开口及口盖对柱面壳压缩稳定性的影响.结果表明:开口大大降低了柱面壳的轴压屈曲强度;口盖可以部分恢复其强度,但很难达到开口之前的水平.进行了开口加口盖经编织物铺层三分之一柱面壳轴向压缩试验,其轴压屈曲强度比用平面织物制造的相同结构的降低很多.为了探究其轴压屈曲强度比同类结构偏低很多的原因,进行了非均匀加载复合材料柱面壳模型有限元分析.结果表明:柱面壳边界不均匀加载会降低其承载能力,根据柱面壳刚度分布制定边界载荷可以提高其承载能力.

Effect of opening and boundary conditions on compressive buckling properties of composite one-third cylindrical shell

The compressive buckling properties of three types of composite one-third cylindrical shells were studied, including intact shell, shell with reinforcement around the opening hole and shell with opening hole and cover. The effect of opening and cover on compressive stability of cylindrical shell was analyzed through the axial compressive buckling strength of three typical composite cylindrical shells. The results show that the opening hole significantly decreases the axial compressive buckling strength. Although axial compressive buckling strength can be restored partly by applying a cover, it can hardly be restored as it was. Axial compressive tests of warp knitting fabric composite one-third cylindrical shells with opening hole and cover were conducted. Compared with the identical structures made of flat knitting composites, the axial compressive buckling strength decreases obviously. In order to explore the cause for the serious axial compressive buckling strength drop, finite element analysis of composite one-third cylindrical shell model with nonuniform loading was conducted. The numerical results show that nonuniform boundary loading decreases the bearing capability and designing the boundary loading according to shell stiffness distribution can improve the bearing capability.