Song Shun-cheng

ITERATIVE METHOD USING CONSISTENT MASS MATRIX IN AXISYMMETRICAL FINITE ELEMENT ANALYSIS OF HYPERVELOCITY IMPACT

We present in this paper an iterative method using consistent mass matrix in axisymmetrical finite element analysis of hypervelocity impact. To retain the advantage of integration on an element-by-element basis which is at the heart of modern hydrocodes, we suggest that the first step should be to solve for accelerations at an advanced time step by using the lumped mass approach, then iterate using a consistent mass matrix to improve the estimate. Examples are given to show the improved resolution with the new method.

Numerical simulation for formed projectile of depleted uranium alloy

The numerical simulation for forming projectile of depleted uranium alloy with the SPH (Smooth Particle Hydrodynamic) algorithm was presented. In the computations the artifical pressures of detonation were used, i. e., the spatial distribution and time distribution were given artificially. To describe the deformed behaviors of the depleted uranium alloy under high pressure and high strain rate, the Johnson-Cook model of materials was introduced. From the numerical simulation the formed projectile velocity, projectile geometry and the minimum of the height of detonation are obtained.

The sliding surface algorithms in three-dimensional dynamic finite element code

In this paper, the sliding surface algorithms in dynamic finite element analysis of high velocity impact are presented. With these algorithms, the momentum and the angular momentum of the element can be conserved. The calculated examples show that the calculation using these algorithms in dynamic finite element analysis of high velocity is valid and stable.

The application of boundary element method in stress analysis of autofretted tube with notch

In this paper, the boundary element method is applied to investigate the internal stale of stress of autofretted tube with notch and the calculated results are important in the practical design.In this paper, the boundary element method is applied to investigate the internal stale of stress of autofretted tube with notch and the calculated results are important in the practical design.

The application of compatible stress iterative method in dynamic finite element analysis of high velocity impact

There is a common difficulty in elastic-plastic impact·codes such as EPICNONSAP.etc..Most of these codes use the simple linear functions usually taken fromstatic problem to represent the displacement components.In such finite elementformulation,the stress components are constant in each element and they are discontinuousin any two neighboring elements.Therefore,the bases of using the virtual work principle insuch elements are unreliable.In this paper,we introduce a new method,namely,thecompatible stress iterative method,to eliminate the above-said difficulty.The calculatedexamples show that the calculation using the new method in dynamic finite element analysisof high velocity impact is valid and stable,and the element stiffness can be somewhatreduced.

New Algorithm of Coupling Element-Free Galerkin with Finite Element Method

Through the construction of a new ramp function, the element-free Galerkin method and finite element coupling method were applied to the whole field, and was made fit for the structure of element nodes within the interface regions, both satisfying the essential boundary conditions and deploying meshless nodes and finite elements in a convenient and flexible way, which can meet the requirements of computation for complicated field. The comparison between the results of the present study and the corresponding analytical solutions shows this method is feasible and effective.

The boundary expanding-contracting principle

In paper [5], we proposed the boundary expanding-contracting principle and the boundary expanding-contracting method (BECM). In this paper we make some complemental statements and detailed proofs about the principle.

The application and extension of Sachs method

In this paper, we present the simplification of Sachs formulas for the measurement and calculation of the residual stresses of the cylinder only with the plane stresses. Furthermore, we present the method for the measurement and calculation of the residual stresses of the cylinder not only with the finite length but with the longitudinal stress. These can be applied to the investigation on the residual stresses of the autofretted gun tube.