Finite Element Refinement Analysis For The Critical Load Of The Single-Layer Spherical Reticulated Shells

The stability analysis is the key issues of the design of the single-layer reticulated shell. The stability and load bearing capacity of the reticulated shell can be showed by the whole process load-displacement curve. Also research on the load-displacement curve is a more accurate way to grasp of structural strength, joint stiffness, and the initial imperfections influence on reticulated shell.Welded hollow spherical joint is widely used in reticulated shell, and has an important influence on the stability of the reticulated shell. Through span and span ratio of shell, initial imperfections, and load apply are important influencing factors for the stability of reticulated shell, but these factors has been done a very in-depth research before. So this article will on the basis of previous studies, focusing how the welded hollow spherical joints affect the stability of the reticulated shell. The finite element numerical model is constituted by shell181 element, which from the finite element analytical software ANSYS. Considering the reticulated shell type and the computing speed limit, we select a representative modal-K6(2) reticulated shell as the analytical model. The content of research will be divided as the following three parts:The first part is about the traditional beam element modal analysis and compare with the shell element modal analysis. By using the two methods to analyze the K6(2) model, compare the results of the two methods to find the same and difference, then determine the next research. The second part is research how the welded hollow spherical joints parameters (the wall thickness of the ball and the ball diameter) impact the reticulated shell. Establish elaborate shell element analysis modals for different joints parameters, by numerical calculation obtain the whole process load-displacement curve, displacement cloud, stress cloud, plastic cloud of different parameters, then get the conclusion. The last part is research how the welding area material change, welding defect and initial imperfection impact the load bearing capacity of reticulated shell, and get the conclusion.Also we have consider the size influence by select and analyze a correspond to actually size shell element modal, compare with the beam element modal analysis, and prove the correctness of the before conclusions.