INVESTIGATION ON STABILITY ANALYSIS METHOD OF SINGLE LAYER LATTICED SHELLS

To accurately analyze the integral stability of single layer latticed shells with initial geometric imperfections, nearly 1300 elasto-plastic load-displacement analyses of K8 single layer latticed shell were carried out to investigate the accuracy and feasibility of different analysis methods. Four different rise-to-span ratios of K8 single layer latticed shell were considered, and the analysis methods employed herein were the random imperfection mode method, the consistent mode imperfection method and the N-order eigenvalue imperfection mode method. The results show that the random imperfection mode method can evaluate the influence of initial geometric imperfections on structural stability more reasonably, but the calculation cost is quite large. To obtain the statistical characteristic of the stability bearing capacity coefficient samples, the number of space samples should be no less than 100. ‘3σ’ principle is suggested to determine the stability bearing capacity coefficient by using the random imperfection mode method. Utilizing the first-order buckling mode to simulate the distribution of initial geometric imperfection may fail to obtain the most unfavorable stability bearing capacity. The N-order eigenvalue imperfection mode method can generate a reasonable stability bearing capacity which meets the requirement of ‘3σ’ principle with less calculation, and moreover, it can evaluate the stability performance of single layer latticed shell reasonably. The N is suggested to be 20 when using the N-order eigenvalue imperfection mode method.