Probabilistic Buckling Ability Of Semi-Rigid Single-Layer Kewitte Reticulated Domes With Geometrical Imperfections

The single-layer reticulated shell has the characteristics of light weight and high strength,and has been widely used in large structures such as stadiums,subway stations and theaters in recent years.In practical engineering,the phenomenon of structural collapse accidents have been caused because of insufficient understanding and improper design.However,the research of scholars is mainly about the qualitative analysis of the overall stability of reticulated shells,The quantitative analysis,especially the probability distribution of buckling load of reticulated shell structures,needs to be further explored.This paper take Kewitte single-layer reticulated shells as the research object,firstly,Matlab numerical analysis software is used to generate random variables,secondly,the two-element method has been introduced to realize the simulation of the semi-stiffness characteristics of reticulated shell joints,thirdly,a numerical method that considers both the joint semi-rigidity and random geometric defects has been used to analysis the influences of joint stiffness,joint installation error,random initial curvature and direction on the buckling capacity of reticulated shell.The main research contents and conclusions are as follows:（1）The stability analysis theory of reticulated shell structure based on ANSYS is systematically described,mainly including the concept of structural stability,types of reticulated shell structure instability and instability factors,reticulated shell structure stability analysis methods,etc.Based on this,the structure analysis simulation process of this research is proposed.（2）The establish of member initial curvature,semi-rigid joint,imperfection member with semi-rigid joint and joint installation error.The General finite element software ANSYS is used to analyze the influence of the amplitude,direction,shape of the imperfection member and joint installation error on the semi-rigid single-layer reticulated shell structure.The results show that the reticulated shell is significantly affected by the amplitude of the defect of the member,but insensitive to the initial curvature direction and shape of the member,when the load capacity of the Kewitte single-layer reticulated shell is analyzed.With the increase of the size of the structure,the sensitivity of the range of load capacity to geometric defects decreases.（3）The influence of the randomness of the initial curvature of members on the load capacity of Kewitte-S and Kewitte-D reticulated shells is studied.The results show that the non-randomness reticulated shells model can be used to analyze the randomness reticulated shells model in practical engineering.（4）The probability distribution law of the buckling load factor of the reticulated shell with geometric imperfections is deeply studied,and the probability distribution is obtained to satisfy the lognormal distribution.Furthermore,The formula about the logarithmic mean and logarithmic standard deviation reduction factor of the buckling load coefficient of the reticulated shell with geometric imperfections is fitted out,and it is change with the joint stiffness.Thus,the ultimate buckling load of the reticulated shell is obtained.which provides an accurate and practical analysis method for the stability load capacity analysis of Kewitte single-layer reticulated shell structure.