On Mixed Mode Crack Propagation Analysis Based on VCCM (Virtual Crack Closure-Integral Method) for Tetrahedral Finite Element

2010 ◽  
Author(s):  
Hiroshi Okada ◽  
Hiroshi Kawai ◽  
Takashi Tokuda ◽  
Yasuyoshi Fukui
Keyword(s):  
Finite Element ◽  
Crack Propagation ◽  
Crack Closure ◽  
Integral Method ◽  
Three Dimensional ◽  
Finite Element Program ◽  
Propagation Analysis ◽  
Element Program ◽  
Analysis System ◽  
Automatic Mesh

The authors have been developing a crack propagation analysis system that can model arbitrary shaped cracks in three-dimensional solids. In the system, automatic mesh generation program, parallel/large finite element program (ADVENTURE_Solid) and virtual crack closure-integral method (VCCM) for the quadratic tetrahedral finite element are used as its key-components. In this paper, the components in the crack propagation system are briefly described and some demonstration problems are presented for an illustrative purposes.

Three-Dimensional Crack Propagation Analysis Based on VCCM (Virtual Crack Closure-Integral Method) for Tetrahedral Finite Element

2008 ◽  
Vol 33-37 ◽  
pp. 901-906 ◽  
Author(s):  
Hiroshi Okada ◽  
Hiroshi Kawai ◽  
Kousuke Araki ◽  
Tsubasa Miyazaki
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Crack Propagation ◽  
Crack Closure ◽  
Mesh Generation ◽  
Integral Method ◽  
Three Dimensional ◽  
Automatic Mesh Generation ◽  
Tetrahedral Element ◽  
Automatic Mesh

This paper describes the development of a software to perform three-dimensional crack propagation analyses. The software is based on the conventional finite element method with second order tetrahedral element and an automatic mesh generation software. Hexahedral finite elements have historically been used in fracture analyses and methodologies to compute the crack parameters have been developed for the hexahedral elements. In present research, the authors have developed a VCCM (virtual crack closure-integral method) for the second order tetrahedral finite element. Use of the tetrahedral element allows us to utilize an automatic mesh generation software. The direction and rate of crack propagation are predicted based on the stress intensity factors and the shape of crack is updated. Hence, a software package containing the modules for mesh generation, for finite element analysis, for stress intensity factor evaluation, for predicting the rate and the direction of crack propagation and for updating crack configuration, can be developed.

Static and Dynamic Analyses of the LSES Hull Structure

1978 ◽  
Vol 22 (02) ◽  
pp. 110-122
Author(s):  
A. S. Hananel ◽  
E. J. Dent ◽  
E. J. Philips ◽  
S. H. Chang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Surface Effect ◽  
Three Dimensional ◽  
Element Model ◽  
Finite Element Program ◽  
Hull Structure ◽  
Surface Effect Ship ◽  
Hull Design ◽  
Element Program

To avoid the conservativeness in the large surface-effect ship hull design which results from simplifying assumptions in the stress analysis, the hull structure was analyzed as a three-dimensional elastic body. The NASTRAN finite-element program, level 15.0, was selected for use in this analysis as the most suitable program available. A finite-element model representing the true hull stiffness was used in obtaining the internal load and displacement distributions. The inertia effect of the ship masses was included with each set of static loads. This was done by using the Static Analysis with Inertia Relief solution included in NASTRAN. The stress redistribution around cutouts in the hull was treated in a separate study. The interaction between hull and deckhouse was investigated by attaching a model of the deckhouse onto the hull model, and then solving for the appropriate load conditions. The natural frequencies were obtained using a reduced finite-element model of both the hull and hull/deckhouse combination. A new technique was developed for determining the dynamic stresses and their proper superposition on the static stresses.

Plastic Deformation Theory Application in Finite Element Analysis

2012 ◽  
Vol 594-597 ◽  
pp. 2723-2726
Author(s):  
Wen Shan Lin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Deformation Theory ◽  
Three Dimensional ◽  
Constitutive Laws ◽  
Constitutive Law ◽  
Element Analysis ◽  
Finite Element Program ◽  
Theory Of Plasticity ◽  
Element Program

In the present study, the constitutive law of the deformation theory of plasticity has been derived. And that develop the two-dimensional and three-dimensional finite element program. The results of finite element and analytic of plasticity are compared to verify the derived the constitutive law of the deformation theory and the FEM program. At plastic stage, the constitutive laws of the deformation theory can be expressed as the linear elastic constitutive laws. But, it must be modified by iteration of the secant modulus and the effective Poisson’s ratio. Make it easier to develop finite element program. Finite element solution and analytic solution of plasticity theory comparison show the answers are the same. It shows the derivation of the constitutive law of the deformation theory of plasticity and finite element analysis program is the accuracy.

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