Mode I stress intensity factor with various crack types

Ehab Samir Mohamed Mohamed Soliman

doi:10.3221/igf-esis.59.31

Ehab Samir Mohamed Mohamed Soliman

Open Access

https://doi.org/10.3221/igf-esis.59.31

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Abstract

Presence of cracks in mechanical components needs much attention, where the stress field is affected by cracks and the propagation of cracks may be occurred causing the damage. The objective of this paper is to present an investigation of crack type effect on crack severity in a finite plate. Three cases of cracked plate with three different types of cracks are assumed in this work, i.e., single edge crack, center crack and double edge crack. 2D numerical models of cases of cracked plate are established in finite element analysis (FEA), ANSYS software by adopting PLANE 183 element. Values of FEA mode I stress intensity factor SIF and Von-Mises stress at crack apex are determined for cases of cracked plate under tensile stress with different values. To identify the crack severity, the comparison of FEA results for different cracked cases is made. The comparison showed that, single edge cracked plate (SECP) has the maximum values of mode I SIF and Von-Mises stress at crack apex, i.e. the greatest crack severity is considered. Also, values of FEA Von-Mises stress at crack apex for center cracked plate (CCP) are moderate and for double edge cracked plate (DECP) are the minimum. Besides, in case of high crack lengths, it is found that, FEA results of mode I SIF in case of (CCP) are higher than those of in case of (DECP). Consequently, crack severity is considered as moderate in case of (CCP) and the minimum in case of (DECP). Empirical formulas are used to approximately estimate mode I SIF for all the case studies of cracked plate in this study and the results are compared to those of FEA. A good agreement between analytical and FEA results has been showed by this comparison.

Highlights

Cracks in engineering components often cause serious local stress concentration and may cause to fracture damage and to failure of these components [1]
F EA were performed for cases of cracked finite plate with three types of crack, single edge crack, center crack and double edge crack under tensile stress with different values, the numerical values of Von-Mises stress and mode I stress intensity factor (SIF) are obtained
From the comparison of the finite element analysis (FEA) results for the three types of crack, it is observed that the FEA values of Von-Mises stress and mode I SIF at crack tip are the maximum in case of single edge cracked plate

Summary

Introduction

Cracks in engineering components often cause serious local stress concentration and may cause to fracture damage and to failure of these components [1]. The severity of the crack is denoted by the stress intensity factor [18], so in the present work, evaluation of mode I SIF using finite element method is carried out to investigate the effect of crack type on crack severity in a 2D finite plate subjected to tensile uniaxial loading. For this purpose, the 2D numerical models of single edge cracked plate (SECP), center cracked plate (CCP) and double edge cracked plate (DECP) are developed using finite element analysis (FEA), ANSYS.

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