Zhongwei Zhao

Simplified numerical method for latticed shells that considers member geometric imperfection and semi-rigid joints:

Most finite element models of actual projects established in general finite element software are rigidly connected or connected by hinge joints. Member imperfection cannot be considered in such models, which is inconsistent with the actual situation in most projects. To estimate the influences of joint stiffness and member imperfection on the mechanical behavior of latticed shell structures, double elements and imperfect members were combined in this study. First, the accuracies of double elements and imperfect members were validated. Then, they were combined to establish imperfect elements with semi-rigid joints. The accuracy of imperfect elements with semi-rigid joints was also validated, and the relationship between joint stiffness and that of double elements was deduced. The findings validated that imperfect elements with semi-rigid joints could consider semi-rigid joints and imperfect members simultaneously and with high accuracy. In addition, imperfect elements with semi-rigid joints could be constructed conveniently in general finite element software.

Mechanical behavior of single-layer reticulated shell connected by welded hollow spherical joints with considering welding residual stress

The welded hollow spherical joints (WHSJ) have been widely used in space lattice structures. There have been many researchers investigating the mechanical behavior of WHSJ. But few literatures that considered the influence of welding residual stress can be found, let alone the integral structure analysis considering welding residual stress. In this paper, welding residual stress of WHSJ was firstly obtained by conducting thermal elastic–plastic analysis. Then, influence of welding residual stress on mechanical behavior of WHSJ was investigated. Secondary development of finite element software ANSYS was conducted, and the welding residual stress was applied as initial load. Finally, the mechanical behavior of a single-layer reticulated shell was investigated by considering residual stress. By using the method proposed in this paper, the simulation of welding process needs to be conducted only once to get the residual stress field of the integral structure. Amazing computational cost was avoided, and it makes it possible to investigate the influence of welding residual stress on integral structures.

Investigations on buckling behavior of single-layer reticulated shell with emphasis on considering welding residual stress

Investigation of welding residual stress on the mechanical behavior of the entire structures is a very difficult work to do due to the amazing computational resource required. It is very necessary to access the influence of welding residual stress on mechanical behavior of absolute welding structures, buckling behavior especially. The residual stress will decrease the component stiffness and then the critical load of the entire structures. In this paper, a method was proposed to access the influence of welding residual stress on the entire structure and was adopted to calculate its influence on buckling behavior of a practical absolute welding structure. The results indicate that the welding residual stress has significant influence on buckling behavior of the structure. The method proposed in this paper is the foundation of further study on influence of welding residual stress.