scholarly journals An evaluation of the loading condition on mixed-mode stress intensity factors for CTST specimens made of 2024-T351 aluminum alloy

2021 ◽  
Author(s):  
Afshin Khatammanesh ◽  
Khalil Farhangdoost ◽  
Danial Ghahremani-Moghadam
Keyword(s):  
Aluminum Alloy ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Mixed Mode ◽  
Integral Approach ◽  
Unstable Fracture ◽  
Pure Mode ◽  
Loading Conditions ◽  
Intensity Factors ◽  
Mode Iii

In this research paper, the unstable fracture of 2024-T351 aluminum alloy is studied under a variety of in-plane and out-of-plane mixed-mode loading conditions including pure mode I and pure mode III loadings. A recently proposed loading device with compact tension shear tearing (CTST) specimens is employed for performing fracture experiments. Three-dimensional finite element analyses using the M-integral approach are conducted to derive the stress intensity factors distributions along the crack front for different mixed-mode configurations. The numerical results reveals that the coupled effect of modes II and III can be observed under mixed-modes I/II, I/III and I/II/III loading conditions. Furthermore, the values of stress intensity factors at the midsection of the specimens are used to predict the critical loads based on different mixed-mode criteria. A good consistency is observed between the theoretical predictions of the criteria and the experimental results for different loading conditions.

Three-Dimensional Mode Separation to Obtain Stress Intensity Factors

2006 ◽  
Author(s):  
Pei Gu ◽  
R. J. Asaro
Keyword(s):  
Stress Intensity ◽  
Crack Propagation ◽  
Stress Intensity Factors ◽  
Three Dimensional ◽  
Integral Approach ◽  
Mode I ◽  
Mode Ii ◽  
Intensity Factors ◽  
Mode Iii ◽  
Mode Separation

For mixed-mode loading at a crack tip under small-scale yielding condition, mode I, mode II and mode III stress intensity factors control the crack propagation. This paper discusses three-dimensional mode separation to obtain the three stress intensity factors using the interaction integral approach. The 2D interaction integral approach to obtain mode I and mode II stress intensity factors is derived to 3D arbitrary crack configuration for mode I, mode II and mode III stress intensity factors. The method is implemented in a finite element code using domain integral method and numerical examples show good convergence for the domains around the crack tip. A complete solution for the three stress intensity factors is obtained for a bar with inclined crack face to the cross-section from numerical calculations. The solution for the bar is plotted into curves in terms of a set of non-dimensional parameters for practical engineering purpose. From the solution, mode mixity along the crack front and its implication to the direction of crack propagation is discussed.

Fracture Criterion of Woven Glass-Epoxy Composite Using a New Modified Mixed-Mode Loading Fixture

2016 ◽  
Vol 08 (02) ◽  
pp. 1650015 ◽  
Author(s):  
Moharram Shameli ◽  
Naghdali Choupani
Keyword(s):  
Composite Material ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Mixed Mode ◽  
Epoxy Composite ◽  
Mixed Mode Fracture ◽  
Pure Mode ◽  
Mixed Mode Loading ◽  
Intensity Factors ◽  
Mode Fracture

In this study, experimental and numerical investigation of the interlaminar fracture behavior of woven glass-epoxy composite was performed under static mixed-mode loading conditions. A new modified mixed-mode loading fixture was employed for this purpose. Woven glass-epoxy composite sheet was produced by hand lay-up method and post-cured in an autoclave set. Butterfly samples were prepared by saw water machine. Mixed-mode fracture tests from pure mode-I to pure mode-II were performed. A finite element analysis was performed and nondimensional stress intensity factors of butterfly samples were computed and a polynomial fit was proposed to evaluate the stress intensity factors of an interlaminar crack subjected to various mixed-mode loadings using new designed fixture. The results indicated that the composite material used in this study is tougher in shear loading conditions and weaker in tensile loadings. For studied composite material, the interlaminar mixed-mode fracture data were according to the strain energy release rates by power-law criterion with the exponents [Formula: see text], [Formula: see text]

On the Crack Propagation Trajectory of Central Cracked Plates under Mixed Mode Loading Conditions

2011 ◽  
Vol 462-463 ◽  
pp. 154-159
Author(s):  
Miloud Souiyah ◽  
Andanastuti Muchtar ◽  
Ahmad Kamal Ariffin
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Crack Propagation ◽  
Stress Intensity Factors ◽  
Mixed Mode ◽  
Loading Conditions ◽  
Intensity Factors ◽  
Element Analysis ◽  
Cracked Plates ◽  
Fortran Language

A Finite Element (FE) programme for crack propagation was developed by using a source code written in the FORTRAN language to evaluate the Stress Intensity Factors (SIFs) and to predict the crack propagation trajectory. In this study, a Central Cracked Plate (CCP) with two holes under mixed mode (I & II) loading conditions is considered. Finite Element Analysis (FEA) combined with the concepts of Linear Elastic Fracture Mechanics (LEFM) provides a practical and convenient means to study the fracture and crack growth of the solid materials. The Displacement Extrapolation Technique (DET) is performed on this work in order to compute the stress intensity factors (SIFs) during the crack propagation. Additionally, to validate the capability and the reliability of this developed FE programme, the results of the current study are compared with experimental results from the literature.

A Surface Crack in Shells Under Mixed-Mode Loading Conditions

1988 ◽  
Vol 55 (4) ◽  
pp. 795-804 ◽  
Author(s):  
P. F. Joseph ◽  
F. Erdogan
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Surface Crack ◽  
Mixed Mode ◽  
Shallow Shell ◽  
Crack Problem ◽  
Three Dimensional ◽  
Loading Conditions ◽  
Intensity Factors ◽  
Crack Problems

The problem of a shallow shell containing a surface crack and subjected to general loading conditions is considered. It is shown that, as in the three-dimensional elasticity formulation, the mode I state can be separated whereas modes II and III remain coupled. A line spring model is developed to formulate the part-through crack problem under mixed-mode conditions. A shallow shell of arbitrary curvature having a part-through crack located on the outer or the inner surface of the shell is then considered. Reissner’s transverse shear theory is used to formulate the problem by assuming that the shell is subjected to all five moment and stress resultants. The uncoupled antisymmetric problem is solved for cylindrical and toroidal shells having a surface crack in various orientations and the primary and the secondary stress intensity factors are given. The results show that, unlike the through crack problems, in surface cracks the effect of shell curvature on the stress intensity factors is relatively insignificant.

Effects of Thickness on Fracture Toughness of Carbon/Polyester Composite

2011 ◽  
Vol 471-472 ◽  
pp. 886-891
Author(s):  
Mohammad Hossein Heydari ◽  
Naghdali Choupani
Keyword(s):  
Fracture Toughness ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Mixed Mode ◽  
Mode I ◽  
Mode Ii ◽  
Pure Mode ◽  
Intensity Factors ◽  
Interlaminar Fracture ◽  
Polyester Composite

The aim of this paper is to evaluate interlaminar fracture toughness and non dimensional stress intensity factors of woven Carbon-Polyester composite based on numerical and experimental methods. A modified version of Arcan specimen was employed to conduct a mixed-mode fracture test using a special loading device. By changing the loading angle, α, from 0° to 90°, mode-I, mode-II and all mixed-mode data were created. The finite element analysis was performed with Abaqus software. The interaction j-integral was used to separate the mixed mode stress intensity factors and energy release rate at the crack tip under different loading conditions and different thickness of specimens. The results of fracture toughness tests revealed that the interlaminar fracture of composite is strong under the shearing-mode loading but weaker to the opening- mode loading. It can be seen that by increasing the thickness of the composite specimen, non dimensional stress intensity factors for pure mode I (α=0°) and pure mode II (α=90° ) loading conditions were decreased.

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