Nonlinear Structural Analysis Method Of Fiber Beam-column Element Research Based On Explicit Algorithm

Nonlinear numerical simulation study of structures under severe earthquakes is oneof the hot areas of seismic research. Under earthquake action, structures enter into thestrong nonlinear state, Previous numerical simulation method based on implicit requiressolving the overall stiffness matrix and calculating the simultaneous equations in eachiteration, this process needs to take up a considerable amount of computing resourcesand memory space, and it always lead to non-convergence for highly nonlinearproblems. Compared with implicit algorithms, the explicit algorithms integrate theequation of balance by explicit time, avoid the solving of stiffness matrix and iteratively,it can solve the non-convergence problems of numerical caused by negative stiffness.Fiber model was a truss model between macroscopic and microscopic models. Inrecent years, fiber model has been used widely in the field of nonlinear structuralanalysis, but most of them were based on implicit algorithm. Due to the nonlinearity ofconcrete material, especially in the softening stage, the negative stiffness of structurewas projecting. Although some methods of calculation had been proposed to overcomenon-convergence, but the actual effect was not satisfactory. The fiber model and explicitalgorithm was attempted to combine in this paper, and explicit algorithm based on fiberbeam element was established, as a new element, it was embedded in the finite elementsoftware of ABAQUS by secondary development. It can play the advantages of fibermodel effectively in dealing with nonlinear problems of structure and the features ofstrong convergence. So that it can solve the structural problems of calculation innonlinear stage. It provides a practical method of analysis when structures enter into thestage of nonlinear.In order to verify the validity of the model developed in this paper, the reliability ofthe model developed in this paper was verified whether static analysis or dynamicanalysis by a series of component tests and numerical simulation shaking table testreciprocating load. Compared the results of the model with the results of implicitalgorithm, the computational accuracy and efficiency of the model developed in thispaper were better than the implicit algorithm, the model developed in this paper can beused as an effective tool for seismic performance assessment.