大矢跨比单层球面网壳弹塑性稳定性研究

Elasto-plastic stability of large rise-span ratios single-layer reticulated domes

为全面认识大矢跨比球面网壳的弹塑性稳定性能，利用ANSYS软件及自编的前后处理程序，有计划地针对132例矢跨比为1／4～1／2的大矢跨比K8型单层球面网壳进行弹性、弹塑性稳定性能分析，并对其中典型算例的塑性发展状况进行了全过程跟踪分析．考察网壳的屈曲模态，分析初始几何缺陷、矢跨比，材料非线性对网壳弹塑性极限承载力的影响．结果表明：大矢跨比情况下，初始几何缺陷的存在会导致网壳的极限承载力降低50％，材料非线性对极限承载力的影响也明显大于常用矢跨比情况，塑性折减系数达到0．4，网壳极易发生提前失稳．建议适当提高大矢跨比球面网壳的稳定性验算安全系数．

To further understand elasto -plastic stability behaviors of single -layer reticulated domes with large rise -span ratios ,both elasto -plastic and elastic behaviors of 132 domes with rise -span ratios in a range from 1/4 to 1/2 were analyzed. The analysis was concudted by ANSYS and self- compiled pre -process and post - process programs. Development of plastic deformations of typical cases were studied based on their complete - process curves. The effect of buckling modes, initial geometrical imperfection, rise - span ratios and material nonlinearity on elasto -plastic critical loads of reticulated domes are investigated. Results reveal that the initial imperfection will reduced the critical loads by 50% the effect of material nonlinearity is also amplified, and the plastic reduced coefficients can reach 0. 4 by statistical analysis. This kind of structures is sensitive to instability failure, a higher safety coefficient is suggested to promote the reliability level of single -layer reticulated domes with large rise- span ratios.