A modified three-dimensional virtual crack closure technique for calculating stress intensity factors with arbitrarily shaped finite element mesh arrangements across the crack front

2020 ◽  
Vol 109 ◽  
pp. 102695
Author(s):  
Xin Zhao ◽  
Zong-Lai Mo ◽  
Zhuo-Yu Guo ◽  
Jun Li
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Crack Closure ◽  
Stress Intensity Factors ◽  
Crack Front ◽  
Three Dimensional ◽  
Virtual Crack Closure Technique ◽  
Intensity Factors ◽  
Closure Technique ◽  
Element Mesh

Quarter-Point Elements Are Unnecessary for the VCCT

2020 ◽  
Vol 87 (8) ◽  
Author(s):  
Elad Farkash ◽  
Leslie Banks-Sills
Keyword(s):  
Stress Intensity ◽  
Energy Release ◽  
Crack Closure ◽  
Stress Intensity Factors ◽  
Virtual Crack Closure Technique ◽  
Intensity Factors ◽  
Release Rates ◽  
Closure Technique ◽  
Established Method ◽  
Energy Release Rates

Abstract The virtual crack closure technique (VCCT) is a well-established method for determining energy release rates and stress intensity factors in homogeneous, isotropic materials. It has been implemented with four-noded, eight-noded, quarter-point, and other higher order elements. It is most convenient and accurate when used with eight-noded, isoparametric elements. VCCT produces less accurate results when used with quarter-point elements. Yet, this method continues to be employed with quarter-point elements. It is strongly recommended to use VCCT with regular eight-noded elements. Three examples will be presented to illustrate the inaccuracy when using quarter-point elements with VCCT.

A Goal Oriented Numerical Simulation Approach for Computing Stress Intensity Factors in Bimaterials

2008 ◽  
Vol 575-578 ◽  
pp. 249-254 ◽  
Author(s):  
Z.C. Xuan ◽  
J.W. Peng
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Finite Element Mesh ◽  
Lower And Upper Bounds ◽  
Intensity Factors ◽  
Element Mesh ◽  
Local Stresses ◽  
Element Error ◽  
Quantities Of Interest

We present a method for computing the stress intensity factors in bimaterials based on the goal oriented finite element error estimate. The goal oriented analysis focuses on computing the bounds on the local quantities of interest, e.g. local stresses, local displacements, stress intensity factors etc, of a structure, and with the bounds obtained on the coarse finite element mesh we can obtain the quantities of interest with nearly the same accuracy as that obtained on the fine finite element mesh. In this paper the stress intensity factors in bimaterials are first formulated as explicit computable linear function of the displacements by means of the two-points extrapolation method. Then the goal oriented finite element method is used to compute the lower and upper bounds on the stress intensity factors, and the average of the bounds is considered as a prediction of the stress intensity factor. At last, the stress intensity factors, 0 K and r K , in bimaterials are computed with the proposed method to show its efficiency.

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