scholarly journals Stress intensity factors for mixed-mode crack growth in imitation models under biaxial loading

2020 ◽  
Vol 14 (53) ◽  
pp. 210-222
Author(s):  
Rustam Yarullin ◽  
V.N. Shlyannikov ◽  
I.S. Ishtyriakov ◽  
M.M. Yakovlev
2007 ◽  
Vol 348-349 ◽  
pp. 585-588
Author(s):  
Henning Schütte ◽  
Kianoush Molla-Abbasi

The aim of the presentation is to highlight the influence of the kink, developing at the beginning of mixed-mode crack growth, on the propagation behavior of the crack. Le et al. [1] have shown that the variational principle of a body containing a crack results in the principle of maximum energy release rate incorporating the stress intensity factors of the kinked crack. Here the influence of the kink and the kinking angle, resulting in a singular field around the corner, on the crack growth is analyzed. The generalized stress intensity factors at the kinks corner are computed with the help of a FEM strategy. The influence of these on the T-stresses and the plastic energy dissipated at the kink is determined using a small scale yielding approach. The impact of these results on mixed-mode crack propagation is discussed.


2021 ◽  
Vol 11 (7) ◽  
pp. 2975
Author(s):  
Abdulnaser M. Alshoaibi

The aim of this paper is to simulate the propagation of linear elastic crack in 3D structures using the latest innovation developed using Ansys software, which is the Separating Morphing and Adaptive Remeshing Technology (SMART), in order to enable automatic remeshing during a simulation of fracture behaviors. The ANSYS Mechanical APDL 19.2 (Ansys, Inc., Canonsburg, PA, USA), is used by employing a special mechanism in ANSYS, which is the smart crack growth method, to accurately predict the crack propagation paths and associated stress intensity factors. For accurate prediction of the mixed-mode stress intensity factors (SIFs), the interaction integral technique has been employed. This approach is used for the prediction of the mixed-mode SIFs in the three-point bending beam, which has six different configurations: three configurations with holes, and the other three without holes involving the linear elastic fracture mechanics (LEFM) assumption. The results indicated that the growth of the crack was attracted to the hole and changes its trajectory to reach the hole or floats by the hole and grows when the hole is missing. For verification, the data available in the open literature on experimental crack path trajectories and stress intensity factors were compared with computational study results, and very good agreement was found.


2021 ◽  
Vol 11 (13) ◽  
pp. 5953
Author(s):  
Abdulnaser M. Alshoaibi

The purpose of this research was to present a simulation modelling of a crack propagation trajectory in linear elastic material subjected to mixed-mode loadings and investigate the effects of the existence of a hole and geometrical thickness on fatigue crack growth and fatigue life under constant amplitude loading. For various geometry thickness, mixed-mode (I/II) fatigue crack growth studies were carried out to utilize a single edge cracked plate with three holes and compact tension shear specimens with various loading angles. Smart Crack Growth Technology, a new feature in ANSYS, was used in ANSYS Mechanical APDL 19.2 to predict the cracks’ propagation trajectory and their consequent fatigue life associated with evaluating the stress intensity factors. The maximum circumferential stress criterion is implemented as a direction criterion under linear elastic fracture mechanics (LEFM). According to the hole position, the results demonstrate that the fatigue crack grows towards the hole due to the unbalanced stresses on the hole induced crack tip. The results of this simulation are verified in terms of crack growth paths, stress intensity factors, and fatigue life under mixed-mode load conditions, with several crack growth studies published in the literature showing consistent results.


Author(s):  
Srikant Ranjan ◽  
Nagaraj K. Arakere

A comprehensive fracture mechanics based life prediction methodology is presented for FCC (Face Centered Cubic) single crystal components, based on computation of stress intensity factors (SIFs), and modeling the crystallographic fatigue crack growth process, under mixed-mode loading conditions. The 3D finite element numerical procedure presented for computing SIFs for anisotropic materials under mixed-mode loading is very general, and not just specific to FCC single crystals. Stress intensity factors for a Brazilian Disc (BD) specimen are presented for the crack on the {111} plane in the 〈101〉 and 〈121〉 directions, which represent the primary and secondary slip directions. Variation of SIFs as a function of thickness is also presented. Modeling of the crystallographic fatigue crack growth (FCG) behavior is performed by using the resolved shear stress intensity coefficient (RSSIC), Krss. This parameter is sensitive to the grain orientation and is based on the resolved shear stresses on the slip planes at the crack tip, which is useful in identifying the active crack plane as well as predicting the crack growth direction. A multiaxial fatigue crack driving force parameter, ΔKrss, was quantified, which can be used to predict the FCG rate and hence life in single crystal components subject to mixed mode fatigue loading.


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