Computational Analysis of the AFM Specimen on Mixed-Mode II and III Fracture

2010 ◽  
Vol 452-453 ◽  
pp. 173-176 ◽  
Author(s):  
Qing Fen Li ◽  
Li Zhu ◽  
Friedrich G. Buchholz ◽  
Sheng Yuan Yan
Keyword(s):  
Mixed Mode ◽  
Strain Energy Release ◽  
Shear Loading ◽  
Mode Ii ◽  
Loading Conditions ◽  
Mode Iii ◽  
Plane Shear ◽  
Loading Mode ◽  
Out Of Plane ◽  
Global Deformation

Some results of 3D finite element analyses of the all fracture modes (AFM) specimen on mixed-mode II and III fracture are presented in this paper. The computational fracture analysis is based on the calculation of separated strain energy release rates (SERRs) along the crack front by the modified virtual crack closure integral (MVCCI)-method and the commercially available FE-code ANSYS. Calculation results show that under pure in-plane shear loading (mode II), not only the mode II, but also the mode III loading conditions, are generated owing to the Poission’s ratio effects. Similarly, under pure out-of-plane shear loading (mode III), besides the mode III, the mode II loading conditions are induced due to the global deformation. Nevertheless, once in-plane and out-of-plane shear loadings are superimposed, the fracture behavior appears more complex. Further discussion is given associate with some previous study.

Asymptotic Crack-Tip Fields in Perfectly Plastic Solids Under Mixed Mode II/III Loading Conditions

2006 ◽  
Vol 129 (4) ◽  
pp. 664-669
Author(s):  
J. Pan ◽  
P.-C. Lin
Keyword(s):  
Mixed Mode ◽  
Crack Tip ◽  
Shear Loading ◽  
Mode Ii ◽  
Pure Mode ◽  
Loading Conditions ◽  
Mode Iii ◽  
Plane Shear ◽  
Crack Tip Fields ◽  
Perfectly Plastic

In this paper, governing equations and solutions for asymptotic singular and nonsingular crack-tip sectors in perfectly plastic materials are first summarized under combined in-plane and out-of-plane shear loading conditions. The crack-tip fields under mixed mode II/III loading conditions are then investigated. An assembly of crack-tip sectors is adopted with stress discontinuities along the border of the two constant stress sectors. The solutions of the crack-tip fields under pure mode II, mixed mode II/III, and nearly pure mode III loading conditions are presented. The trends of the angular variations of the mixed mode II/III crack-tip stresses agree with those of the available computational analysis and the asymptotic analysis for low strain hardening materials. The pure mode II crack-tip stresses are similar to those of Hutchinson, and the nearly pure mode III stresses are similar to those of the pure mode III crack-tip field of Rice.

Asymptotic Crack-Tip Fields in Perfectly Plastic Solids Under Combined In-Plane and Out-of-Plane Shear Loading Conditions

2005 ◽  
Author(s):  
J. Pan
Keyword(s):  
Mixed Mode ◽  
Crack Tip ◽  
Shear Loading ◽  
Mode Ii ◽  
Pure Mode ◽  
Loading Conditions ◽  
Mode Iii ◽  
Plane Shear ◽  
Crack Tip Fields ◽  
Perfectly Plastic

In this paper, governing equations and solutions for asymptotic singular and non-singular crack-tip sectors in perfectly plastic materials are first summarized under combined in-plane and out-of-plane shear loading conditions. The crack-tip fields under mixed mode II/III loading conditions are then investigated. An assembly of crack-tip sectors is adopted with stress discontinuities along the border of the two constant stress sectors. The solutions of the crack-tip fields under pure mode II, mixed mode II/III, and nearly pure mode III loading conditions are presented. The trends of the angular variations of the mixed mode II/III crack-tip stresses agree with those of the available computational analysis and the asymptotic analysis for low strain hardening materials. The pure mode II crack-tip stresses are similar to those of Hutchinson and the nearly pure mode III stresses are similar to those of the pure mode III crack-tip field of Rice.

In-plane and out-of-plane shear fracture toughness of rocks

2021 ◽  
Author(s):  
Bahador Bahrami ◽  
Morteza Nejati ◽  
Majid Reza Ayatollahi ◽  
Thomas Dreisner
Keyword(s):  
Fracture Toughness ◽  
Shear Fracture ◽  
Shear Loading ◽  
Mode Ii ◽  
Mode Iii ◽  
Brazilian Disk ◽  
Plane Shear ◽  
Double Edge ◽  
Out Of Plane ◽  
Tensile Fracturing

<p><span>Rocks in the subsurface are exposed to high amount of confinement which can potentially suppress the formation or the development of tensile-based cracks and thus, give rise to shear-based fracture growth. However, measuring the shear fracture toughness of rocks have been studied less in the literature, as providing the required confinement to force the shear fracturing precede tensile fracturing is not an easy task. In the current study, two new tests namely the double-edge notched Brazilian disk (DNBD) and the axially double-edge notched Brazilian disk (ANBD) are proposed to measure the in-plane (true mode II) and the out-of-plane (true mode III) shear fracture toughness of rocks, </span><span>K</span><sub><span>IIc </span></sub><span>and </span><span>K</span><sub><span>IIIc</span></sub><span>, respectively. We use the term </span><span>true </span><span>to emphasis that not only sustains the crack shear loading, but also the type of fracturing is shear-based. Finite element method is used to study the variations of stress field around the crack tip in these tests and to prove the applicability of the tests in providing mode II and mode III loading conditions. It is argued that both tests are straightforward and have several advantages compared to the existing ones. The effectiveness of the tests is empirically corroborated by conducting some experiments on Bedretto Granite. The pulverized surface of fracture in both the tests denotes the existence of friction which indicate the shear-based nature of fracture. Finally, the measured values of </span><span>K</span><sub><span>IIc </span></sub><span>and </span><span>K</span><sub><span>IIIc </span></sub><span>for Bedretto granite are compared to each other and to the reported values of </span><span>K</span><sub><span>Ic </span></sub><span>in the literature. It is shown that </span><span>K</span><span>IIc </span><span>and </span><span>K</span><span>IIIc </span><span>values are close to each other while both are more than two times greater than </span><span>K</span><span>Ic</span><span>.</span></p>

Mixed-Mode [I/III] Fracture Simulation of Rubber

2014 ◽  
Vol 931-932 ◽  
pp. 1053-1057
Author(s):  
Kiatisak Permpipat ◽  
Petch Jearanaisilawong
Keyword(s):  
Mixed Mode ◽  
Shear Loading ◽  
Mode I ◽  
Mixed Mode Fracture ◽  
Tearing Mode ◽  
Mode Iii ◽  
Plane Shear ◽  
Finite Element Software ◽  
Fracture Simulation ◽  
Out Of Plane

The objective of this work is to develop fracture simulations of rubber undergoing a combined tensile and out-of-plane shear loading. Rubber sheets are tested under mode-I (opening mode), mode-III (tearing mode) and mixed-mode [I/II of fracture. The experiments are simulated in finite element software to evaluate the J-integral for each mode of deformation. Comparison between simulation and testing results are in good agreement. The simulations serve as test cases and evaluation tools for the development of mixed mode fracture criterion of rubber.

Experimental and theoretical investigation of mixed mode I/III brittle fracture of U-notched polystyrene components

2017 ◽  
Vol 53 (1) ◽  
pp. 15-25 ◽  
Author(s):  
A.R. Torabi ◽  
Behnam Saboori
Keyword(s):  
Brittle Fracture ◽  
Mixed Mode ◽  
General Purpose ◽  
Shear Loading ◽  
Mode I ◽  
Mean Stress ◽  
Plane Shear ◽  
Out Of Plane ◽  
Notch Tip ◽  
Stress Criteria

Brittle fracture of components made of the general-purpose polystyrene and weakened by an edge U-notch under combined tension/out-of-plane shear loading conditions (mixed mode I/III) has not been studied yet experimentally or theoretically. In this research, a recently developed loading fixture is employed for experimentally investigating the fracture of U-notched general-purpose polystyrene samples with various notch tip radii of 0.5, 1, 2 and 4 mm when they are subjected to different combinations of tension/out-of-plane shear. The samples are fabricated with four different notch tip radii with the purpose of assessing the influence of this geometrical parameter. The experimental values of fracture load and out-of-plane fracture angle are theoretically predicted by the two stress-based criteria of point stress and mean stress lately extended to general loading case of mixed mode I/II/III. It is shown that both the point stress and mean stress criteria provide acceptable predictions to fracture behavior of U-notched general-purpose polystyrene specimens. The critical distances needed for the point stress and mean stress criteria are determined based on the experimental results of the U-notched samples tested under pure mode I loading. No meaningful difference is found between the fracture loads and fracture initiation angles predicted by the point stress and mean stress criteria. It is also observed that as the mode III contribution in the applied mixed mode I/III loading increases, a larger total external load is needed for the fracture of U-notched general-purpose polystyrene specimens to occur.

Mixed Mode I/III Crack-Tip Fields for Perfectly Plastic Mises Materials

2007 ◽  
Author(s):  
J. Pan
Keyword(s):  
Mixed Mode ◽  
Crack Tip ◽  
Shear Loading ◽  
Mode I ◽  
Pure Mode ◽  
Loading Conditions ◽  
Plane Shear ◽  
Tensile Stresses ◽  
Crack Tip Fields ◽  
Perfectly Plastic

In this paper, governing equations and solutions for asymptotic singular and non-singular crack-tip sectors in perfectly plastic Mises materials are first reviewed under combined in-plane and out-of-plane shear loading conditions. The crack-tip fields under mixed mode I/III loading conditions are then investigated. One assembly of four crack-tip plastic sectors is adopted with stress discontinuities along the border of two constant stress sectors. The solutions of the crack-tip fields under pure mode I and mixed mode I/III loading conditions are presented. The crack-tip fields under pure mode I and mixed mode I/III loading conditions give fully-plastic solutions with various hydrostatic tensile stresses ahead of the crack tip. The characteristics of the mode I limits of fully plastic crack-tip fields with different hydrostatic tensile stresses ahead of the crack tip agree well the past computational results under pure mode I with different constraint conditions.

scholarly journals Mixed mode I/II/III fracture assessment of PMMA using a new test fixture

2019 ◽  
Vol 300 ◽  
pp. 11003 ◽  
Author(s):  
Seyed Mohammad Javad Razavi ◽  
Haakon Lie Hokstad ◽  
Filippo Berto
Keyword(s):  
Mixed Mode ◽  
Loading Condition ◽  
Real Life ◽  
Shear Loading ◽  
Mode I ◽  
Mixed Mode Fracture ◽  
Mixed Mode Loading ◽  
Plane Shear ◽  
Out Of Plane ◽  
Fracture Tests

Brittle and quasi-brittle fracture has been recognized as the main failure mechanism in various structural components. Due to complexity of the components’ geometry and loading condition, a combination of tensile, in-plane shear and out of plane shear loading results in final fracture of cracked components. Hence, it is important to evaluate the fracture behaviour of different materials under a mixed mode loading condition which is close to the real-life loading of the structural parts. In this paper, a new loading device for general mixed mode I/II/III fracture tests is designed and recommended. Finite element analyses are performed to study the fracture parameters of the test specimens under different mixed mode loading conditions. According to the numerical results, the designed loading fixture can generate a wide varieties of mode mixities from pure tensile mode to pure in-plane and out of plane shear modes. Fracture tests were performed on pre-cracked specimens made of polymethyl methacrylate (PMMA) to check the accuracy of the proposed fixture. The proposed fixture was proved to be applicable for general mixed mode fracture evaluation of brittle materials.

scholarly journals Analysis of Elastic Medium with Nonconcentric Two Circular Inclusions under Out-of-Plane Shear Loading.

1998 ◽  
Vol 64 (618) ◽  
pp. 438-444 ◽  
Author(s):  
Kenichi HIRASHIMA ◽  
Shigerou NAKANE ◽  
Mutsumi MIYAGAWA ◽  
Shinji KIKUCHI
Keyword(s):  
Elastic Medium ◽  
Shear Loading ◽  
Plane Shear ◽  
Out Of Plane
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