Papers by Keyword: Elasto-Plastic Analysis

Abstract: The elasto-plastic analysis using the triple shear unified yield criterion and the cavity expansion theory is devoted to soil around the tubular pile. When the influence of the intermediate principal stress is considered, the driving effect of the tubular pile is studied. The relationship between plastic zone, the limit expansion pressure, the radial stresses and the parameter b is also obtained. The results show that the radius of plastic zone is decreased and the limit expansion pressure is increased, at the same radius, the radial stress is also increased, because of the effect of intermediate principal stress.

Abstract: Since the Wenchuan earthquake in 2008, the earthquake-resistant consideration in structure design is highlighted in the Chinese code. This paper introduces a dynamic elasto-plastic method in structure modeling using ABAQUS finite element analysis. In the first stage, structural models are transferred into ABAQUS INP files. Then the user subroutines are given to describe the elastic and plastic behaviors of both concrete and steel materials. Finally, the models are analyzed in an ABAQUS implicit or explicit analysis. The result can suggest the weakness of the building and provide advisement in reinforcing the structure.

Abstract: The elasto-plastic analysis of reinforced concrete square columns was introduced to study the relationship between lateral force and curvature by using the open source program OpenSees. A pseudo static test on the inverted "T" shape reinforced concrete square column was conducted for the comparative analysis. The results indicated that the lateral force calculated by program agree with experimental data with an axial load ratio of 0.33. The calculated yield lateral force was 29.7 kN, the error was lower than 7% compared with experimental results. In addition, the cross-section curvature were obtained, which were difficult to obtain through the traditional experimental study, the calculated yield curvature was 1.825×10^-5. The calculated results with different axial load ratios were presented in this paper, which showed that both the yield lateral force and curvature of reinforced concrete square columns were increased with low axial load ratio, and at the same time it could reduce some experimental work by using computer simulation.

Abstract: Based on the nonlinear dynamic time history analysis, a multi-span RC highway bridge with high damping rubber bearings was studied, to investigate the damping ratio and seismic performance of the bridge and high damping rubber bearings compared with the rubber bearings. Results show that the application of high damping rubber bearings can reduce the seismic response of substructures of the bridge under longitudinal and transversal seismic excitations to some extent. But what is more important is that high damping rubber bearings wont suffer shear and displacement failure which may happen on rubber bearings. As a result, the pounding response and residual displacement can be dispelled.

Abstract: In this paper, element free Galerkin method (EFGM) has been applied to solve nonlinear solid mechanics problems using updated Lagrangian approach. The nonlinear equations have been solved using Newton Raphson method. An associative J2 flow rule and isotropic hardening has been used for the modelling of elasto-plastic material behaviour. Elastic predictor and plastic corrector algorithm has been used for the integration of incremental stress-strain relation. Few test problems involving large deformations have been simulated and the results obtained by EFGM have been compared with those obtained by FEM.

Abstract: In large deformation problems, the contribution of nonlinear terms is quite significant. Hence, components/structures involving large deformation must be analysed using non-linear theories. In this paper, element free Galerkin method (EFGM) has been applied to solve large deformation problems using updated Lagrangian approach. Geometrically nonlinear problems have been simulated assuming linear elastic material behaviour. The results obtained by EFGM have been compared with those obtained by FEM and analytical solutions. An elasto-plastic edge crack problem has been solved using nonlinear material behaviour and large deformation kinematics.

Abstract: Reinforced concrete core walls have become major lateral force structure units in high-rise building. Base on fiber model, the process simulation of a seismic behavior testing on reinforced concrete core walls is presented. The Perform-3D software is adopted to perform static pushover analysis for reinforced concrete core walls, and results from the simulation match well with those from the tests. It is shown that the fiber model is valid for numerical simulation analysis of core walls. Damage development sequence of core wall specimen and yielding condition of each member are analyzed which coincide well with the experimental results. On this basis, effects of more design parameters on bearing capacity and deformation performance are systematically analyzed, and conclusions which is valuable for theoretical research and engineering design are obtained. The influence of axial compression ratio, height-width ratio, reinforcement ratio of coupling beam and span-depth ratio of coupling beam on the seismic performance of core walls are analyzed systemically.

Abstract: Elasto-plastic analysis of seismic responses of valve hall structures were carried out by using finite element software, and the effect of seismic waves on the seismic responses of the valve hall structures and suspension equipments were studied. Results show that significant torsional responses of the structure can be found under longitudinal and 3D earthquake actions. Under 3D earthquake actions, the seismic responses of the suspension valves are much more significant than those under 1D earthquake actions, the maximum tensile force of the suspenders is about twice of that under 1D action. The seismic responses of the suspension valves under vertical earthquake actions are much stronger than those under horizontal earthquake actions, when suffering strong earthquake actions; the maximum vertical acceleration of the suspension valves is about 4 times of that under horizontal earthquake actions. It is recommended that the effects of 3D earthquake actions on the structure should be considered in seismic response analysis of the valve hall structure.

Abstract: Aim at one tall building structure model, which is a nonlinear three-dimensional finite element model. ANSYS FEM software is used to set up the structure model, proceeding modal analysis on natural vibration period and vibration model; ANSYS FEM software is used to import El Centro and Taft acceleration time-travel curves, which are used in 7 degree film, proceeding elasto-plastic analysis, and compared with the result of PKPM software earthquake static effect, the layer displacement calculation results contrast between two software shows it is consistent, but contrary results occurs in ISDA. So for the similar project design auxiliary FEM analysis is needed; Seven degree rarely met earthquake acceleration time-travel data and larger seismic peak acceleration time-travel imported to research the plastic development.

Abstract: A finite element program for elasto-plastic analysis of 3D beams and frame structures under large displacement/rotations is developed. The element is Timoshenko beam element based on mechanics of continuum. Constitutive equations for large displacements/rotations in elastic stage are expressed in an explicit way which is suitable for programming. The modification of constitutive equation is presented for the analysis of elasto-plastic problems. A fiber model is adopted for the calculation of stiffness matrix and internal forces. For solution of nonlinear finite element equations, general displacement control method and semi-modified stiffness matrix method is adopted. The results of numerical experimentation show that the program work well for 3D beams and frame structures under elasto-plastic large displacement/rotations.