Research On The Universal Discrete Shell Element Of RC Panel Member

The frequent occurrence of earthquake disasters in the world has caused incalculable losses to human beings.The damage caused by the collapse of buildings is especially serious.As a result of the limitation of test environment,cost and other problem,some domestic and foreign scholars have put forward various methods of numerical simulation analysis to research the nonlinear reaction and collapse process of structure under earthquake.And Discrete Element Method and Finite Element Method are more applied.In the present discrete element method,domestic and foreign scholars have put forward a variety of element models for the structure under cyclic load analysis And the segment-multi-spring model based on beam-column member and multi-spring shell element model based on panel member have higher computational precision and efficiency.But in this model,the shear spring in the spring set in the element is constructed based on the section level.The calculation parameters are difficult to be determined,especially for complex components,such as shear wall with hole.At the same time,because the axial spring is built based on material level,they are not coordinated.Moreover,the multi-spring shell element model is limited to the rectangular element.Its element configuration is too simple,and it is difficult ito make the element division in the simulation of complex structure.This paper makes an in-depth study on the segment-multi-spring model and multi-spring shell element model.And the main work is as follows:1 Through collecting and reading domestic and foreign literature,this paper summarizes the analysis of discrete element method in the field of structural engineering development present situation and lucubrate the segment-multi-spring model and multi-spring shell element model.2.In this paper,the segment-multi-spring model based on the beam-column member is modified.The shear springs in the segment-multi-spring model is modified to the material level by the section level.At the same time,the torsion spring is removed,and the torsional force of the element is reflected by the shear springs.The theoretical basis of the force performance description of the modified spring set is more explicit,and the determination of the calculation parameters is simpler.3.In this psper,the universal discrete shell element model is proposed.It includes general quadrilateral element and triangle element.The spring configuration of the shell element is also unified with the spring configuration in the segment-multi-spring model.This model can be applied to the force analysis of various simple or complex shape wall panel members and complex structure,and perfect the disadvantages that element configuration of multi-spring shell element model is too simple.4.Based on the existing discrete element program SMS-Collapse,this paper makes secondary development and presents the modified multi-spring element model and the proposed universal discrete shell element model in the program.In this paper,the preprocessor in this program is optimized,and the finite element model is transformed into discrete element model.It makes the process of complex modeling and element division simplify.And the calculation procedure is modified according to the modified calculation theory.5.This paper makes simulation analysis for the cantilever column based on the segment-multi-spring model,and research the influence of the the calculation results and calculation efficiency by the spring number in the element section.The calculation results matches well with the experimental results.It is proved that the modified segment-multi-spring model is reasonable in this paper.6.This paper makes simulation analysis for the shear wall without hole and shear wall with hole based on the universal discrete shell element model.And this paper mainly analyzes and discusses the influence by multi-spring shell element model with different element size,different number of springs cross the section thickness or height direction and whether the function of restraint of reinforcement on concrete is considered.At the same time,this paper make analysis and simulation with the influence of the nonlinear properties of shear wall by the boundary element and axial compression ratio.The calculation results matches well with the experimental results.It is proved that the universal discrete shell element model proposed in this paper is reasonable.The improved multi-spring element model and the universal discrete shell element model can be applied to nonlinear analysis of various truss or shell components.And it has high accuracy and high efficiency.The multi-spring element model in this paper makes up for the disadvantage of the lack of precision and narrow scope of application of simulation analysis in the nonlinear properties of the complex structure by the previous model.And it can be used to simulate the force analysis and collapse process of structures or components under earthquake.