Papers by Keyword: Elasto-Plastic

Abstract: The article analyzed the forced state of the surrounding rock and the tunnel lining for Fu longping double-decked tunnel by the Elasto-plastic finite element method. In the analysis, DP’s yield criterion was employed for the elasto-plastic characteristics of materials. It studied the construction method with the theory, and guided the construction for the double-decked tunnel ,too.

Abstract: A coupled elastoplastic damage model is proposed for the description of anisotropic concrete under compression-dominated stresses. The model is applied to typical concrete in various loading conditions. Damage evolution law and plastic damage coupling are described by using the framework of irreversible thermodynamics.

Abstract: The elastic stress and strain fields in an elasto-plastic circular cross-section bar with semicircular groove subjected to uniaxial tension are systematically investigated using the finite element method. It is found that the stress and strain concentrations are different, especially after the partial region near the groove root yielding. The coupled influences of the loading levels and Poisson’s ratios on the stress and strain concentrations are examined. The maximum of strain concentration factor is always at the groove root, but the maximum of stress concentration factor is at the groove root only while the loading levels are lower.

Abstract: It established Multi-Support excitations time history analysis model Based on large quality method. It took large span reticulated shell for example, chose EL-centro wave to carry on the spectrum analysis and time history analysis with direct integral method, studied the deformation capacity and destruction features of structure under rare earthquake of magnitude of 8, and put forward the seismic performance’s related measures and suggestions in elasto-plastic analysis of the large span reticulated shell under multi-support excitations for the actual engineering reference in design.

Abstract: The stratum uneven settlement of tunnel is main factors that cause damage of tunnel longitudinal structure. a 3d numerical model is established for the force and deformation calculation of tunnel structure based on the elastoplastic theory. In the model, soil material is elastoplastic, and its constitutive model is Mohr Coulomb, the element type of soil is a three-dimensional solid, the element type of tunnel lining structure is space shell element, and tunnel settlement joint is three-dimensional linear spring. Calculation shows that, this calculation model is able to fully consider the impact of tunnel uneven settlement in all factors, and can simulate the vertical force and deformation behavior of tunnel structure in complex ground formation conditions. Research conclusion gives the vertical force and deformation of the tunnel structure under the condition of the stratum uneven settlement. It is very important reference for the longitudinal design and calculation of the tunnel lining structure.

Abstract: When the loading sustained by the foundation is large, employing piled raft foundation is one of the best solutions. In the elasto-plastic design of piled raft, piles could improve the differential settlement and reduce raft thickness. As the raft sustains high earth and water pressures, by reducing the span length of raft and excavation depth, one can get economic design. Using elasto-plastic property of the pile is a better method to avoid increasing the pile length and pile diameter and making full capacity of the piled raft foundation in design compared to normal piled raft. With adoption of few small diameter piles, the raft thickness could be reduced significantly. This makes it much better than raft foundation.

Abstract: In this paper, the co-rotational total Lagrangian forms of finite element formulations are derived to make elasto-plastic analysis for plane steel frames either under increasing external loading at ambient temperature or under constant external loading at elevated temperatures. Geometric nonlinearity and thermal-expansion effect are taken into account. A series of programs are developed based on the formulations. To verify the accuracy and efficiency of the nonlinear finite element programs, a couple of numerical benchmark tests are carried out. And the results are in a good agreement with solutions from literature. The effects of nonlinear terms of the stiffness matrices on the computational results are investigated in detail. It is demonstrated that the influence of geometric nonlinearity on the incremental step by step finite element analysis for plane steel frames in fire is limited.

Abstract: This paper investigates nonlinear elasto-plastic analysis of the dynamic response of composite spherical shells base on the isotropic hardening and flow rule theorem. elasto-plastic strain-hardening is expressed at this stage and the plastic strain obtains to combine with elastic strain to present the elasto-plastic constitutive relation of composite spherical shells. Analytical solutions of the governing equations are based on the Chebyshev spectral collocation methods and then compare results with ABAQUS FEM. In numerical example, the effective of different external loads on the nonlinear elastic and nonlinear elasto-plastic of composite spherical shell are discussed in details.

Abstract: In port crane industry, the surface hardening technique is widely used in order to improve the strength of wheel. From the practical experience, when the high hardness hardened wheel is used, the danger of sudden break of the wheel is increased. How the hardness of the wheel effect the fatigue life of the wheel is not studied theoretically. In this paper, the contact stresses in wheel with different hardness have been analyzed by applying three-dimensional finite element model. Based on this model, the ANSYS10.0 finite element software is used. Three different plastic slopes are used to simulate three different hardness materials. Surface hardened wheel with three different hardness materials, and three different vertical loads are applied. The effect of hardness of a surface hardened wheel is discussed by comparing the contact stresses from the numerical results. The reason of the sudden failure of the high hardness hardened wheel is discussed, and some suggestions are given in choosing hardness of the hardened wheel.

Abstract: This study aims to clarify the process conditions of the radial compression of aluminum tube. It provides a model that predicts not only the correct punch load for compression, but also the precise final shape of products after unloading, based on the compression properties of the material and the geometry of the tools used. An elasto-plastic incremental finite-element computer code, based on an updated Lagrangian formulation, was developed to simulate the radial compression of aluminum tube. In particular, selective reduced integration was adopted to formulate the stiffness matrix. The extended r-minimum technique was used to deal with the elasto-plastic state and contact problems at the tool-metal interface. A series of simulations were performed to validate the formulation in the theory, leading to the development of the computer codes. The whole deformation history and the distribution of stress and strain during the forming process were obtained by carefully considering the moving boundary condition in the finite-element method. Results in this study clearly demonstrated that the computer code for simulating the radial compression of aluminum tube was efficient.