T -stress effects on crack deflection: Straight vs. curved crack advance

2016 ◽  
Vol 60 ◽  
pp. 52-57 ◽  
Author(s):  
A. Sapora ◽  
P. Cornetti ◽  
V. Mantič
Keyword(s):  
Crack Deflection ◽  
Crack Advance ◽  
Stress Effects ◽  
Curved Crack ◽  
T Stress

Experimental Investigation of T-Stress Effects on Photoelastic Fringes in Brazilian Disk under Mode II Conditions

2007 ◽  
Vol 348-349 ◽  
pp. 969-972
Author(s):  
Mario Guagliano ◽  
Majid R. Ayatollahi ◽  
Mahnaz Zakeri ◽  
Chiara Colombo
Keyword(s):  
Mode Ii ◽  
Pure Mode ◽  
Brazilian Disk ◽  
Stress Effects ◽  
Stress Changes ◽  
Isochromatic Fringes ◽  
Theoretical Predictions ◽  
T Stress ◽  
Fringe Patterns ◽  
Definition Of

According to classical definition of crack deformation modes, the constant stress term (Tstress) exists only in presence of mode I. However, some studies show that this term can exist in mode II problems as well; and significantly affect the elastic stress field around the crack tip. Based on the previous analytical results, T-stress changes the photoelastic fringe patterns from symmetric closed shapes to asymmetric and discontinuous loops. In this research, the effects of T-stress on the fringe patterns in mode II cracks is investigated experimentally. Test specimens are Brazilian disks made of polycarbonate, and thermal treatment is performed to remove the residual stresses after generation of the cracks. Observed isochromatic fringes are in good agreement with theoretical predictions. Also, experimental results indicate that this specimen contains a negative T-stress in pure mode II condition.

3D Numerical Study on how the Local Effective Stress Intensity Factor Range Can Explain the Fatigue Crack Front Shape

2014 ◽  
Vol 891-892 ◽  
pp. 295-300
Author(s):  
Catherine Gardin ◽  
Saverio Fiordalisi ◽  
Christine Sarrazin-Baudoux ◽  
Jean Petit
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Effective Stress ◽  
Numerical Study ◽  
Stress Intensity Factor Range ◽  
Crack Advance ◽  
Effective Stress Intensity Factor ◽  
Curved Crack ◽  
Shaped Crack

The plasticity-induced crack closure of through-thickness cracks, artificially obtained from short cracks grown in CT specimens of 304L austenitic stainless steel, is numerically simulated using finite elements. Crack advance is incremented step by step, by applying constant ΔK amplitude so as to limit the loading history influence to that of crack length and crack wake. The calculation of the effective stress intensity factor range, ΔKeff, along curved shaped crack fronts simulating real crack fronts, are compared to calculation previously performed for through-thickness straight cracks. The results for the curved crack fronts support that the front curvature is associated to constant ΔKeffamplitude, thus assumed to be the propagation driving force of the crack all along its front.

T-stress evaluation for curved crack problems

2008 ◽  
Vol 198 (1-2) ◽  
pp. 35-50 ◽  
Author(s):  
Y. Z. Chen ◽  
X. Y. Lin
Keyword(s):  
Stress Evaluation ◽  
Curved Crack ◽  
Crack Problems ◽  
T Stress

Crack Deflection from the Interface between Two Orthotropic Materials-Effect of Higher Order Terms in Asymptotic Analysis

2013 ◽  
Vol 577-578 ◽  
pp. 157-160
Author(s):  
Petr Damborský ◽  
Oldřich Ševeček ◽  
Tomáš Profant ◽  
Michal Kotoul
Keyword(s):  
Fracture Criterion ◽  
Input Parameter ◽  
Complex Stress ◽  
Higher Order ◽  
Crack Deflection ◽  
Orthotropic Materials ◽  
Complex Stress Intensity Factor ◽  
Higher Order Terms ◽  
T Stress ◽  
Main Input

The problem of crack deflection from the interface between two orthotropic materials is analyzed using the concept of Finite fracture mechanics and matched asymptotic procedure. A fracture criterion based on the energy approach is introduced for this problem. The main input for such criterion is the complex stress intensity factor calculated e.g. using the two-state integral. However for more precise predictions of the crack propagation also higher order terms of the asymptotic expansion are advisable to involve in the fracture criterion. To this end a T-stress term will be calculated and considered as the second input parameter. The matched asymptotic procedure together with FEM is used to derive the change of the potential energy induced by the incremental crack growth.

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