Papers by Keyword: Finite Deformation

Abstract: Metal orthogonal cutting and blanking are two important forming processes which include material removing. During finite element analyzing, the nonlinear problems of boundary, material and geometry must be considered to obtain the accurate calculating results. In this paper, we present an advanced adaptive remeshing procedure which has the capacities to simulate material removing processes in three dimensions. The sizes of finite elements are well adapted to local conditions which have the high distributions of physical fields using priori and posteriori error estimates. Based on constraint Delaunay Kernel, the unit mesh strategy is proposed to improve the mesh quality. By optimizing of both mesh edges and mesh elements, the mesh shape qualities are strictly controlled as the regular tetrahedrons. In this paper, Johnson-cook model is considered to simulate the elastic-visco-plastical material behaviors. The damage initiation is also judged by Johnson-cook criterion. The finite elements which reach the criterion will be killed and the material removing processes finished step by step. The proposed adaptive remeshing scheme is well present using the simulation of metal orthogonal cutting, milling and blanking processes.

Abstract: The oscillation problem is examined for a rectangular sealing ring composed of a class of transversely isotropic incompressible vulcanized rubber materials about radial direction, where the sealing ring is subjected to a suddenly applied radial load at its inner surface. A nonlinear ordinary differential equation that describes the radial motion of the sealing ring is obtained. It is proved that if the applied load is lower than the critical load, the motion of the rubber ring with time will present a nonlinear periodic oscillation, while if it exceeds the critical load, the motion will increase infinitely with the increasing time and so the rubber ring will be destroyed ultimately.

Abstract: A nonlinear waves equation of an elastic circular rod taking account of finite deformation and transverse Poisson effect is derived by means of Hamilton variation principle in this paper. Nonlinear wave equation and corresponding truncated nonlinear wave equation are solved by the hyperbolic tangent function and cotangent function finite expansion method. Two different types of exact traveling wave solutions, the shock wave solution and the solitary wave solution are obtained. The necessary condition of these solutions existence is given also.

Abstract: In this paper, the problem of finite deformation of a cylindrical rubber tube with an internal rigid tube is examined, where the rubber tube is subjected to axial loads on its two ends. A reasonable mathematic model is formulated by using the nonlinear field theory. Then, the implicit solutions that describe the cases of tension and compression are derived. The influence of end loads, thickness and length on the finite deformation is discussed in detail. Numerical simulations are given simultaneously. It also shows that for a large domain of the middle part of the tube, the deformation is very close to a uniform case, but near the two ends of the tube, the change is very fast, which coincides with the mechanical backgrounds.

Abstract: An analytical model is derived for obtaining the dynamic performance of a thin curved composite piezoelectric beam with variable curvatures for the MEMS piezoelectric vibration energy harvester. The plane curved beam theory with rectangular section is employed to explore the bending and twisting coupling vibration characteristics. In order to satisfy the most available environmental frequencies, which are on the order of 1000Hz, the parameters of the spiraled composite beam bonded with piezoelectric on the surfaces are investigated to provide a method of how to design low resonance beams while keeping the compacting structural assembly. The results indicate the adoption of ANSYS® software to carry out the MEMS piezoelectric vibration energy harvester’s numerical simulation can improve the accuracy of the harvester designing and manufacturing consumedly. And the simulation data also provide a theory analysis foundation for the engineering, design and application of harvester.

Abstract: Recently it has been demonstrated that the classical Prandtl/Reuss theory based on the additive split of the deformation rate contrary to what is believed so far is possible to establish a consistent Eulerian rate formulation for finite elastoplasticity. Here, we attempt to place this Eulerian formulation on the thermodynamic grounds by extending it to a general case with thermal effects.

Abstract: Cartilage and bone are specialized connective tissues composed of roughly the same material: cell embedded in an extracellular matrix, permeated by the network of fibers. Then the properties of cartilage are anisotropic and inhomogeneous structure. At the same time, the structure of cartilage is rather porous allowing fluid to move in and out of the tissue. Thus the properties of cartilage were changed with the fluid content. The objective of this study is to demonstrate that the biomechanical properties of the pericellular matrix vary with depth from the coated cartilage surface, and observed regions of cartilage failure. This objective is achieved by solving problems with the finite element method. The conceptual model was subjected to the boundary conditions of confined compression on porous of cartilage anisotropy. The experimental results were demonstrated that neither the Young’s modulus nor the Poisson’s ratios exhibit the same values when measured along the loading directions. The results were supported an essential functional property of the tissue which the glenoid surface may be susceptible to cartilage degeneration.