Research Of Multi-Spring Models In Reinforced Concrete Beams,Columns And Shells Based On Discrete Element Method

It has been proved to be helpful that people figure out what happens to the structure when earthquake suddenly attacks.Although discrete element method(DEM)has been used in researches mentioned above since 1990s and is actually indeed precious in collapse simulation,DEM still has some weakness.Multi-Spring segment model and Multi-spring shell element model can be used in DEM,but these previous models still lack RC element models like shear wall with holes,T-shape columns and H-shape columns.So,they are difficult to analysis the nonlinear response and collapse damage of large complex frame-wall and shear wall structure.Meanwhile,another reason why previous Multi-spring shell element model act tough in simulation is its axial spring group just consist of one row of steel and concrete springs.This paper focuses on the RC Multi-spring models based on DEM,work is as follows:1.Based on reading a large number of domestic and foreign literature,make a summary of simulation situation especially about DEM in structural engineering.Moreover,developed Multi-Spring segment theoretical model for beam-column members and developed Multi-Spring shell theoretical model for wall-plate members based on DEM are studied.2.This paper improved Multi-spring segment model so that T-shape column and H-shape column element models are involved.At the same time,Multi-spring shell model is improved so that model of shear wall with holes can be involved.This paper also improved axial spring group in the Multi-spring shell model so that moments can be borned in one axial spring group.New models allow elements mismatch each other,so this paper also researched spring topological relations.3.This paper kept developing the SMS-Collapse program so the optimized multi-spring element models can be involved in the program.Elements' and members' topological relations in the plane and out of plane are also optimized.4.Rewrote the SMS-Collapse program so that it can allow parallel processing.5.Find experimental test of RC shear wall with holes and RC T-shape column specimens under low cyclic load,and then use numerical simulation based on this paper to compare with them.The results show that the improved multi-spring shell element model and multi-spring segment element model can precisely simulate RC members' performance,and the program which used models established in the paper runs well.