Finite Element Numerical Analysis Of The Optimum Structure Configuration And Stress State Of Thin Shell Structures

Thin shell structure is widely used in engineering structures because of its rich architectural beauty,strong spanning ability,and high internal space.Relative to the flat plate,the shell plate is generally understood as a compressive member,that is,the flat plate mainly shows bending under lateral load,and the shell plate mainly shows compression under vertical load,and mainly resists the external with compressive stress effect.For concrete members,because bending failure usually starts from tensile failure,the thin shell structure is more conducive to give full play to the material properties of concrete "compressive but not tensile".However,the mechanical response of the thin shell structure under the vertical load should be closely related to the spatial shape of the shell plate,that is,the stress state of the thin shell structure under the vertical load should be closely related to its initial structural configuration Relationship,the so-called structural form.Generally speaking,the thin shell structure should have two stress states under the vertical load: one is the axial stress state,referred to as the axial stress state;the other is both compressed and stressed The state of bending stress is referred to as the state of bending and compression.Obviously,we hope that the thin shell structure can always be under axial load under the vertical load.This is the national fund project(a theoretical and experimental study of an elastic conjugate shell with the best structural shape)supported by this research.,No: 11772072).However,for the conventional design of thin shell structures,many shell plates with different spatial shapes can be designed under the conditions of the same span and height,so the conventional shells are generally subjected to bending and compression under vertical loads Force status.So,for a given span and height,will there always be a minimum bending moment? It also includes the case where the bending moment is zero,that is,the axial compression force state.The research on this issue was first carried out in response to the needs of the National Fund Project(theoretical and experimental research on an elastic conjugate shell with the best structural form,No: 11772072).The general meaning is that if this study can prove that there is always a minimum bending moment for a given span and height,then in the conventional design process of thin shell structures,you can find the maximum stability by finite element calculation The spatial shape of the load-bearing shell plate(that is,the initial structural configuration of the shell),because the minimum bending moment is the maximum stable load-bearing capacity of the shell.In this study,finite element calculations have been performed on seven thin shell structures with different vector heights at a given span.For each vector height,there are 19 shells with different initial structure configurations.Through the finite element calculation of 133 shells,the conclusion that the thin-shell structure always has the smallest bending moment at a given span and height is obtained.This article consists of the following five chapters:The first chapter briefly describes the research significance and research background of the subject,and combines the research status at home and abroad,briefly summarizes the main research content of this article.The second chapter mainly introduces the basic theory of thin shell structure analysis and finite element calculation.Regarding the basic theory of thin-shell structures,two basic assumptions and three types of basic equations(geometric equations,physical equations,and equilibrium equations)are described.Regarding the basic theory of the finite element method,this chapter starts from the central idea of the finite element method and describes the main analysis steps of the finite element method in detail.In Chapter 3,finite element calculations are carried out for shells with different initial configurations.In this chapter,7 groups of 133 shells with different initial structure configurations and different sagittal span ratios are designed,and specific design methods are given.Based on the finite element software ABAQUS,these shells are analyzed and calculated,and the shell bending moments are obtained.,Axial force and stress distribution data.Chapter 4 analyzes and discusses the best structural form of the thin shell structure based on the finite element calculation results.This chapter discusses from two angles within and between groups.The effects of different initial configurations on the bending moment,axial force and stress distribution of the shell are analyzed and discussed.The distribution of the bending moments of the initial structure of the shell with the smallest bending moment value is obtained.The fifth chapter summarizes the research work,obtains relevant conclusions,and prospects for further experimental research and other content.The relevant results and conclusions of this study have certain reference value for the conventional design of thin shell structures.