Continuous Development Of Inelastic Dynamic Time History Analysis Program D-SAP For Super High-rise Building Structures

Since the completion of the basic platform in 2014,the elato-plastic dynamic time history analysis(THA)program D-SAP has developed and integrated 17 commonly used material constitutive models,more than 30 element types and many acceleration and iterative algorithms.It has been successively used for full-process analysis of multiple super high-rise building structures.However,as the demand for structural analysis increases,further improvements are needed in the following aspects.First of all,the materials in D-SAP are mainly 1D,2D concrete and reinforced materials,and the elements are mostly macroscopic elements such as fiber beamcolunmn elements and shell elements.The 3D steel,concrete material and solid elements for the fine modeling of building structures is lacking.Secondly,with the rise of parametric structural design concepts in recent years,structural analysis software is required to have ability of parametric modeling and analysis,which D-SAP lacks in these aspects.Considering the above two requirements,the main work carried out in this paper is as follows:(1)A number of 2D elements and 3D solid elements are integrated into D-SAP.Element stiffness matrix is accurately caculated using appropriate Hammer and Gaussian numerial integration method.Based on a full understanding of D-SAP architecture and finite element theory,five 2D plan stress elements(CPS3,CPS4,CPS6,CPS8 and CPS4I)and five3 D solid elements(C3D4,C3D10,C3D8,C3D20 and C3D8I)are integrated.Among them,the imcompatible element(CPS4I,C3D8I)can eliminate the “shear locking” occurs in bilinear element(CPS4,C3D8).A case of the cantilever beam under lateral forces was implemented to verify the calculation accuracy of ten solid elements.(2)Steel and concrete elasto-plastic materials(3D)are integrated into D-SAP.For elasto-plastic steel materials,the expression of consistent tangent stiffness is deducted based on the rate constitutive equation of mixed hardening,and the implementation process of the radial return mapping algorithm is given.Two kinds of mixed hardening materials are formed through the combination of isotropic hardening model and two kinds of kinematic hardening model(smoothing bilinear hardening and Chaboche hardening).For concrete elasto-plastic materials,the flow chart of the plastic return and the damage calculation was drawn based on the concrete plastic damage model proposed by Grassl,and the 3D concrete plastic damage material code suitable for the D-SAP was written.The correctness of the two material codes is verified by comparison with theory or experment.(3)According to the D-SAP text modeling and analysis command,the application programing interface(API)is created,and on this basis,the interface between D-SAP and the parametric software Grasshopper is realized.132 API functions are implemented using component object module(COM)and active X template library(ATL),which can be used for D-SAP modeling and analysis through “code modeling” on the Visual Studio platform.Node,material,cross-section,element and analysis components were developed using Grasshopper Add-on and D-SAP’s API.The details of conversion from the architectural geometric model to structure model and the use of components are shown through the parametric modeling and analysis process of PC framework.