双层圆柱壳在均匀轴压下的屈曲行为

Buckling behavior of a double-layer cylindrical shell under uniform axial pressure

对双层不锈钢圆柱壳在均匀轴压下的屈曲性能进行研究,分别设计、制作和测量了3个名义相同的双层圆柱薄壳,其长径比均为1.7。通过对试样进行轴向压缩试验获得其载荷位移曲线和极限强度,采用弧长法对试样进行非线性屈曲分析,得到平衡曲线和临界载荷并与试验结果进行对比。另外采用数值分析法研究双层圆柱壳的缺陷敏感性,进而推测出一种用于评估双层圆柱壳承载能力的理论公式。结果表明,双层圆柱壳的平均极限强度约为单层的1.85倍,双层圆柱壳是缺陷敏感结构,其缺陷敏感性与内层壳体缺陷敏感性趋于一致,且双层圆柱壳的缺陷敏感性随长径比的增加而降低,试验结果、数值计算和理论预测具有较高一致性。

In order to study the buckling performance of double-layer(DL)stainless steel cylindrical shells under uniform axial compression,three DL cylindrical shells with nominally identical are designed,fabricated,and measured.The length-to-diameter ratio of all cylindrical shells is 1.7.In this paper,the load-displacement curve and ultimate strength of cylindrical shells are obtained by axial compression test.The arc length method is used to analyze the nonlinear buckling behavior of cylindrical shells;therefore,the equilibrium curve and critical load are obtained and compared with the test results.In addition,the imperfection-sensitivity of DL cylindrical shells is studied by numerical analysis.Furthermore,a theoretical equation for evaluating the load-bearing capacity of DL cylindrical shells is derived.The results reveal that the average ultimate strength of DL cylindrical shells is approximately 1.85 times higher than that of single-layer(SL)cylindrical shells.DL cylindrical shells are imperfection-sensitivity structures.The imperfection-sensitivity of the DL cylindrical shells is consistent with the imperfection-sensitivity of inner shells.Moreover,the imperfection-sensitivity of DL cylinders decreases with the increase in length-to-diameter ratio.The results of the test,numerical,and theoretical approaches are highly consistent.