基于多功能函数的双层球面网壳结构的可靠度及敏感性研究

Reliability and Sensitivity Analysis of Double-Layer Spherical Lattice Shells Using Multiple Performance Functions

以4个矢跨比(1/3、1/4、1/5、1/6)的双层凯威特型球面网壳为研究对象,重点考察了网壳结构的可靠度、敏感性和相关性随荷载等级提高的变化规律。为了深入研究外荷载、杆件的物理属性和几何参数的随机性分别对网壳结构可靠度的影响程度,根据随机变量类型,分别将杆件的横截面面积、弹性模量和屈服强度定义为一个随机变量,继而研究了功能函数对各类型随机变量的敏感性程度;为了全面深入地探讨网壳结构在各等级荷载作用下的受力性能,定义了4种类型的功能函数,包括最大挠度、总塑性应变能、屈服杆件数目和总塑性应变,考察了4种类型功能函数对各随机变量的敏感性程度及功能函数间的相关性;最后,研究了各随机变量敏感性随不同矢跨比的变化规律。

The paper aims to investigate reliability,sensitivity and correlation of four double-layer spherical lattice shells (with rise-to-span ratio of 1/3,1/4,1/5 and 1/6) subjected to several different load levels.To deeply study the effect of external load,physical properties and geometric parameters of chords on reliability of lattice shells,cross-sectional area,modulus of elasticity and yield strength are defined as random variables,according to types of random variables in lattice shells.In order to clarify mechanical performance of four lattice shells,four output indexes,i.e.,maximal deflection,total plastic strain energy,number of yielding members/chords and total plastic strain,are defined into four performance functions,respectively.Furthermore,sensitivity analysis of all random variables to the above-mentioned performance functions and their correlations are extensively carried out.Finally,changing laws of reliability,sensitivity and correlation are investigated in detail with increment of rise-to-span ratio.