Study On The Constitutive Model Of Concrete And Steel For Explicit Dynamic Beam Elements Of ABAQUS

China is one of the worst earthquake disaster countries in the world. With continually development of our country urban construction, more and more complex structures and new structures have emerged. The structures usually enter the elastic-plastic state under earthquake action, and the elastic analysis methods can not truly describe the behavior of structures. Dynamic elastic-plastic analysis of the high-rise structures which have obvious weak parts is required by current specification.Large universal finite element softwares ANSYS, ABAQUS and MSC.MARC are widely used in structures analysis. Scholars have tried to use these software analyzing the structures dynamic elastic-plastic. ABAQUS has strong nonlinear calculation capability, Especially the explicit analysis module can avoid the convergence in implicit analysis. It also can save computer storage space and improve analysis speed by parallel technology when analyzing the structures. But there is no concrete constitutive model and reasonable steel constitutive model in the explicit analysis module of ABAQUS for spatial beam element. In this paper the uniaxial constitutive model of concrete and steel is established, in order to precisely simulate the nonlinear performance of RC column-beam members under seismic loads. The material subroutines of these models are simultaneously developed and applied to the explicit dynamic module of ABAQUS by means of user-defined subroutine interface (VUMAT).1-, Research of the constitutive modelThe constitutive model of concrete which established in this paper are proposed by Kent and Park, improved by Scott BD. The restraint effect of stirrup and the crack surface effect of concrete are included in the purposed concrete constitutive model.There are two constitutive model of steel is established. Bauschinger’s effect are Considered in the uniaxial constitutive model of steel.2n Research of fiber ModelThe three-dimensional fiber beam element model in the explicit analysis module of ABAQUS can simulate the hysteretic performance of RC columns, core concrete is described by rectangular cross-section, concrete cover and reinforced are described by box-type section. The integral point of cross section is equivalent to fiber which can be given different material properties. The mechanical behavior of section can be simulated by integral point.3、RedevelopmentBase on the material stress-strain relationship, the material subroutines of these models are simultaneously developed and applied to the explicit dynamic module of ABAQUS by means of user-defined subroutine interface (VUMAT). 4、numerical simulation of RC column and frameA single RC column is build by using technology of common node. The hysteretic performance of RC columns under cyclic loading is numerically simulated. Compared with the steel constitutive model of ABAQUS, the results show that the model of this paper can more rightly simulate the hysteretic performance of RC columns under the multiaxial load. In this paper a plane frame model is analyzed under the seismic loads, The results of calculation is tally well with test results.The established model can be used to analyzing the nonlinear behavior of RC column-beam element under the multiaxial loading conditions. Especially the biaxial bending coupling effect of the speciments is analyzed accurately. It also can meet the demand of analyzing the nonlinear dynamic response of structures under the seismic loads.