The Research On Structural Seismic Response Based On Energy Analysis

Energy analysis method can well reflect the comprehensive response of structural elasto-plasticity property, structural plastic cumulative effect under earthquake and ground motion properties - ground motion intensity, frequency and duration. Therefore it increasingly obtains engineering extensive attention.The structural seismic response is an process of energy input, transformation and consumption. In this case, the energy analysis method needs to resolve many key issues such as the total input energy of structures and its influencing factors, energy existing forms in structures as well as the energy causing structural damage under earthquake, of which the influencing factors and distribution are also included.In the present study, the energy seismic principle of single-degree-of-freedom and multi-degree-of-freedom systems as well as the static pushover analysis of elastic and inelastic structures are researched. Besides, the finite element method and corresponding finite element software are also used to obtain seismic total input energy, plastic dissipated energy(inelastic hysteretic energy) and ultimate failure energy of structures. The dimensionless plastic dissipated index and failure index are proposed based on energy analysis.The plastic dissipated index is defined as the ratio of structural plastic dissipated energy to total input energy, and the failure index is defined as the ratio of structural total input energy to structural ultimate failure energy. The structural plastic dissipated energy and total input energy are calculated by nonlinear dynamic time history response analysis using the software of ABAQUS, while the structural ultimate failure energy is calculated with the static modal pushover method. As an example, the numerical analysis of a typical structure under earthquake is carried out. The failure index, plastic dissipated index and simulated seismic damage of structure are presented and compared. The distribution of plastic dissipated energy in different storeys and different structural components is also obtained from these calculations under different earthquake intensities .The results verify the correctness and reliability of the proposed method.The corresponding rules of plastic dissipated index and simulated seismic damage of high-rise structures is achieved by the comparison of plastic dissipated index and simulated seismic damage of lots of high-rise structures. So we can use the rules to estimate the seismic damage of high-rise structures. Seismic simulation of a typical high-rise frame-tube structure is carried out by nonlinear dynamic time history response analysis using ABAQUS. The structural plastic dissipated index and plastic dissipated energy distribution along storeys and in different structural components are calculated under the same earthquake wave with different intensities; While the structural plastic dissipated index and plastic dissipated energy distribution along storeys are also calculated under the same intensity with different earthquake waves. The structural corresponding damage configurations are also simulated. The comparison results from the two methods are consistent, which shows that the plastic dissipated index and plastic dissipated energy distribution are valuable for estimating the overall and local damage of structures. Finally, the seismic design project of typical high-rise structure is optimized by energy analysis method.