基于可靠度的单层网壳结构临界稳定承载力计算方法OA北大核心CSTPCD

In order to investigate the reliability-based method for determining of critical stable bearing capacity of single-layer dome structures,the random imperfection modal superposition method is applied and modified for the simulation of the initial geometrical imperfections of single-layer dome structures.Then,a kind of mixed-degree cubature formula is developed to evaluate the first-four statistical moments of stable bearing capacity of structures with accuracy and efficiency.Further,the probability density function of stable bearing capacity is reconstructed by using the shifted generalized lognormal distribution,where the critical stable bearing capacity of structures can be specified given the target reliability index or probability of instability.A hexagonal star dome model and a K8 single-layer dome structure are investigated to validate the effectiveness of the proposed method,respectively.The computational results demonstrate that the proposed method uses the superposition of first-four buckling modes to obtain the probability density function of stable bearing capacity with a higher level of variability.The decreasing trend in stability bearing capacity agrees well with the result obtained from the consistent mode imperfection method.Besides,the value of imperfection amplitude in the current code,which is 1/300 of the span,is also quite conservative.