A new domain-independent interaction integral for solving the stress intensity factors of the materials with complex thermo-mechanical interfaces

2015 ◽  
Vol 49 ◽  
pp. 500-509 ◽  
Author(s):  
Hongjun Yu ◽  
Takayuki Kitamura
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Intensity Factors ◽  
Interaction Integral ◽  
Domain Independent

Computation of dynamic stress intensity factors for cracks in three-dimensional functionally graded solids

2017 ◽  
Vol 233 (5) ◽  
pp. 862-873
Author(s):  
Safa Peyman ◽  
Rahmatollah Ghajar ◽  
Saeed Irani
Keyword(s):  
Stress Intensity ◽  
Functionally Graded Material ◽  
Stress Intensity Factors ◽  
Material Properties ◽  
Dynamic Stress ◽  
Functionally Graded ◽  
Intensity Factors ◽  
Dynamic Stress Intensity Factors ◽  
Interaction Integral ◽  
Graded Material

Dynamic stress intensity factors are important parameters in the dynamic fracture behavior of a cracked body. In this paper, an interaction integral method is utilized to compute the mixed-mode dynamic stress intensity factors of three-dimensional functionally graded material solids. Using a proper definition of actual and auxiliary fields, a new formulation and application of the interaction integral is proposed, which is independent of the derivatives of the material properties. ABAQUS finite element package is applied to analyze the functionally graded material cracked bodies. Accordingly, a user material subroutine is written for implementing the continuous variation of the material properties. Temperature was used as an additional variable to consider the variation of density. A research code is developed to compute the interaction integral. This code is then validated by solving some homogeneous and functionally graded material problems. Furthermore, the effect of the material properties on the dynamic stress intensity factors of FGM bodies with elliptical crack is investigated by taking the sigmoidal model into account. Several important fracture behavior of functionally graded material cracked bodies under dynamic loadings for different material property profiles are explored in detail.

A Novel Approach for Evaluation of Stress Intensity Factors Using X-FEM

2012 ◽  
Vol 446-449 ◽  
pp. 816-823
Author(s):  
Liang Wu ◽  
Li Xing Zhang ◽  
Ya Kun Guo
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Crack Tip ◽  
Strain Energy Release ◽  
Numerical Results ◽  
Intensity Factors ◽  
Interaction Integral ◽  
Novel Approach ◽  
New Energy ◽  
Energy Release Rates

A new energy approach is proposed by coupling the virtual crack extension with the extended finite element method (X-FEM) to extract the Strain Energy Release Rates and then convert it to stress intensity factors. By means of meshes independence of the location and geometry of the crack, the proposed approach avoids the mesh perturbation around the crack tip to compute the stiffness derivatives with respect to a virtual extension of the crack. In comparison to the interaction integral, this combined method is implemented more easily without the post-processing of the numerical results. The effect of different enriched region around the crack tip on the accuracy of results is discussed. Numerical results presented are in excellent agreement with the available analytical and those obtained using the interaction integral.

Investigation of Stress Intensity Factors for an Interface Crack in Multi-Interface Materials Using an Interaction Integral Method

2011 ◽  
Vol 78 (6) ◽  
Author(s):  
Linzhi Wu ◽  
Hongjun Yu ◽  
Licheng Guo ◽  
Qilin He ◽  
Shanyi Du
Keyword(s):  
Stress Intensity ◽  
Interface Crack ◽  
Stress Intensity Factors ◽  
Intensity Factors ◽  
Extended Finite Element ◽  
Material Interfaces ◽  
Interaction Integral ◽  
Crack Problems ◽  
Mode Stress ◽  
Interface Materials

A new interaction integral formulation is derived for obtaining mixed-mode stress intensity factors (SIFs) of an interface crack with the tip close to complicated material interfaces. The method is a conservation integral that relies on two admissible mechanical states (actual and auxiliary fields). By a suitable selection of the auxiliary fields, the domain formulation does not contain any integral related to the material interfaces, which makes it quite convenient to deal with complicated interface problems. The numerical implementation of the derived expression is combined with the extended finite element method (XFEM). According to the numerical calculations, the interaction integral shows good accuracy for straight and curved interface crack problems and exhibits domain-independence for material interfaces. Finally, an interfacial fracture problem is investigated for the representative centrosymmetric structure formed by two constituent materials.

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