There are two models in use today to analyze structural responses when subjected to earthquake ground motions,the Displacement Input Model(DIM)and the Acceleration Input Model(AIM).The time steps used in direct integr...There are two models in use today to analyze structural responses when subjected to earthquake ground motions,the Displacement Input Model(DIM)and the Acceleration Input Model(AIM).The time steps used in direct integration methods for these models are analyzed to examine the suitability of DIM.Numerical results are presented and show that the time-step for DIM is about the same as for AIM,and achieves the same accuracy.This is contrary to previous research that reported that there are several sources of numerical errors associated with the direct application of earthquake displacement loading,and a very small time step is required to define the displacement record and to integrate the dynamic equilibrium equation.It is shown in this paper that DIM is as accurate and suitable as,if not more than,AIM for analyzing the response of a structure to uniformly distributed and spatially varying ground motions.展开更多
In the seismic analysis of extended structures subject to spatially varying motions,the displacement input model instead of acceleration model is usually adopted for accurate results.In this paper,a more detailed and ...In the seismic analysis of extended structures subject to spatially varying motions,the displacement input model instead of acceleration model is usually adopted for accurate results.In this paper,a more detailed and comprehensive analysis of the displacement input model is carried out and the research shows that there exists an unnegligible problem in the current displacement model,which leads to the irrationality and unconvergence of some calculated results such as base shear etc.Based on the situation,an effective method named massless rigid element(MRE)method is presented to solve the problem.Moreover,the rationality and accuracy of the method are further assessed and the method is applied to a transmission tower-line system project using the commercially available structural analysis software SAP2000.The theoretical and numerical analyses indicate that the MRE approach is not only feasible with sufficient computational accuracy but also practical and can be easily implemented using the commercially available finite element software such as SAP2000.展开更多
文摘There are two models in use today to analyze structural responses when subjected to earthquake ground motions,the Displacement Input Model(DIM)and the Acceleration Input Model(AIM).The time steps used in direct integration methods for these models are analyzed to examine the suitability of DIM.Numerical results are presented and show that the time-step for DIM is about the same as for AIM,and achieves the same accuracy.This is contrary to previous research that reported that there are several sources of numerical errors associated with the direct application of earthquake displacement loading,and a very small time step is required to define the displacement record and to integrate the dynamic equilibrium equation.It is shown in this paper that DIM is as accurate and suitable as,if not more than,AIM for analyzing the response of a structure to uniformly distributed and spatially varying ground motions.
基金supported by the Scientific Research Foundation of Central South Universitythe National Natural Science Foundation of China(Grant No.50638010)the Foundation of Ministry of Education for Innovation Group(Grant No.IRT0518)
文摘In the seismic analysis of extended structures subject to spatially varying motions,the displacement input model instead of acceleration model is usually adopted for accurate results.In this paper,a more detailed and comprehensive analysis of the displacement input model is carried out and the research shows that there exists an unnegligible problem in the current displacement model,which leads to the irrationality and unconvergence of some calculated results such as base shear etc.Based on the situation,an effective method named massless rigid element(MRE)method is presented to solve the problem.Moreover,the rationality and accuracy of the method are further assessed and the method is applied to a transmission tower-line system project using the commercially available structural analysis software SAP2000.The theoretical and numerical analyses indicate that the MRE approach is not only feasible with sufficient computational accuracy but also practical and can be easily implemented using the commercially available finite element software such as SAP2000.
