| How to simulate the response of a structure under ground motion more accurately and efficiently is a classic problem.Many studies have shown that the fiber model can better simulate the behavior of components in the non-linear period,and has a higher computing efficiency.The fiber model is to divide the cross-section into many material fibers along the length direction,and each fiber exhibits axial deformation under the action of external force,so it can better consider the axial and bending stress behavior,but cannot consider the shear and torsion effects.Most of the existing research based on fiber models only consider the contribution of elastic shear modulus.When these methods are used to analyze the frame structure,the nonlinear behavior of the cross section due to the large shear stress cannot be accurately simulated,which restricts the structural dynamics under earthquake The accuracy and rationality of performance analysis.To this end,this paper carried out the response analysis of the frame model considering the nonlinear shear effect under the action of ground motion.The specific research contents include:(1)Based on a large number of numerical experiments,a nonlinear shear model suitable for the section of reinforced concrete members is proposed.The model includes parameters such as concrete strength,cross-section height and cross-sectional area,and can be applied to simulation analysis under various working conditions.After verification with the experiment,the model shows better prediction accuracy of the section shear performance.In this paper,Abaqus software is used for simulation analysis.First,the influence of parameters such as concrete strength,steel bar strength,and cross-sectional conditions on the shear behavior of reinforced concrete members is discussed.Then combined with classical mechanical rules,shear force is fitted with a large number of finite element simulation experimental results-Shear stress relationship.(2)Based on the Section Aggregator platform in the Open Sees software,the nonlinear shear model proposed in this paper is integrated with the fiber model,and the dynamic time history analysis of the frame structure considering the nonlinear shear effect is established.Applicability of nonlinear shear model in frame structure analysis.(3)Based on the verified numerical simulation method of the frame structure,taking a typical low ductility structure as an example,the comparative analysis of the frame without considering the shear effect,considering the linear shear effect and considering the nonlinear shear effect in Dynamic time history under the action of rare earthquakes.The results show that the frame considering the nonlinear shear model can more reasonably reflect the actual shear resistance,deformation capacity and energy consumption of the frame under rare earthquakes,and the simulation method without considering shear or considering linear shear is adopted.,Will underestimate the damage degree of the frame and overestimate its overall stiffness and earthquake resistance. |
