Analysis of Failure Mode and Propagation for Crack in Uniaxial Compression

2012 ◽  
Vol 166-169 ◽  
pp. 2929-2932
Author(s):  
Ya Zhen Sun ◽  
Xiao Xing Zhai ◽  
Jie Min Liu
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Failure Mode ◽  
Uniaxial Compression ◽  
Process Analysis ◽  
Failure Process ◽  
Inclined Crack ◽  
Wing Crack ◽  
Dimensionless Stress

This paper analyzed the failure mode for crack in uniaxial compression according to the stress intensity factor, and obtain that the failure mode for crack in uniaxial compression is compression-shear. The wing crack was deformed, after the crack tip initiate. By analyzing the dimensionless stress intensity factor, we obtain that the failure mode for wing crack in uniaxial compression is tension-shear, and we obtain that the dimensionless stress intensity factor for wing crack decreased with inclined angle increased. The inclined crack propagation in uniaxial compression was numerically studied using rock failure process analysis code (rfpa), and obtain that one inclined crack in uniaxial compression formed mode I offset crack parallel to load direction in the end. The numerical results of failure mode are accordance with stress intensity factor.

Revision to Stress Intensity Factor Equations for ASME Section XI Appendix C-4000: Determination of Failure Mode

2018 ◽  
Author(s):  
Kiminobu Hojo ◽  
Steven Xu
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Failure Mode ◽  
Inside Surface ◽  
Screening Procedure ◽  
Real Surface ◽  
Screening Criteria ◽  
Influence Coefficients ◽  
Surface Flaws

In ASME Section XI Appendix C for analytical evaluation of flaws in piping, a screening procedure is prescribed to determine the failure mode and analysis method for the flawed pipe. The end-of-evaluation period flaw dimensions, temperature, material properties, and pipe loadings are considered in the screening procedure. Equations necessary to calculate components of the screening criteria (SC) include stress intensity factor (K) equations. The K-equation for a pipe with a circumferential inside surface flaw in the 2017 Edition Section XI Appendix C-4000 is for a fan-shaped flaw. Real surface flaws are closer to semi-elliptical shape. As part of Section XI Working Group on Pipe Flaw Evaluation (WGPFE) activities, revision to stress intensity factor equations for circumferential surface flaws in Appendix C-4000 has been proposed. The proposed equations include closed-form equations for stress intensity influence coefficients G0 for membrane stress and Ggb for global bending stress for circumferential inside surface flaws. The rationale for the Code changes and technical basis for the proposed stress intensity factor equations are provided in this paper.

Numerical Studies of End Effect on Crack Propagation Behavior of Brittle Specimen Containing Pre-Existing Crack under Uniaxial Compression

2007 ◽  
Vol 353-358 ◽  
pp. 1049-1052
Author(s):  
Ming Li Huang ◽  
Shan Yong Wang ◽  
Wei Lu ◽  
Wan Cheng Zhu
Keyword(s):  
Crack Propagation ◽  
Uniaxial Compression ◽  
Process Analysis ◽  
Failure Process ◽  
End Effect ◽  
Wing Crack ◽  
Propagation Length ◽  
Propagation Behavior ◽  
Numerical Studies ◽  
Crack Propagation Process

In this paper, a Material Failure Process Analysis code (MFPA2D) was employed to investigate the interaction of end effect zone of specimen with the wing crack propagation inside the brittle specimen containing pre-existing flaws under uniaxial compression comparing with the experimental results. The numerical results show that the shorter the distance between the pre-existing flaw and the specimen's end , the slower the crack propagation process and the shorter wing propagation length is , and vice versa. In addition, the end effect zone was also influenced by the wing crack propagation.

Cracking in composites of glass fibres and resin

1978 ◽  
Vol 359 (1697) ◽  
pp. 229-250 ◽  
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Fracture Energy ◽  
Volume Fraction ◽  
Process Analysis ◽  
Fibre Volume Fraction ◽  
Polarized Light ◽  
Critical Stress Intensity Factor ◽  
Glass Fibres

Experiments have been carried out on the propagation of cracks in resin beams containing regularly spaced glass fibres. The effects of the fibre spacing, orientation and surface treatment on the fracture energy and cracking resistance of these composites are discussed with reference to acoustic emission records and polarized light observations of the fracture process. Analysis of curves of load against deflexion shows that the major factor contributing to the fracture energy of the composite is work done against friction between fibre and matrix. It has been suggested that the fracture energy and stress intensity approaches to understanding fractureresistance of composites should give the same result, and indeed some of the results of this work appear to support this view. But a detailed examination of the relative effects on cracking of the fibre spacing and fibre volume fraction - ostensibly the same thing - suggests that the fracture energy is determined by factors somewhat different from those which govern the stress intensity factor. The fracture energy is controlled simply by the fibre content, irrespective of their spacing, whereas the critical stress intensity factor is affected separately by fibre spacing and volume fraction.

The Static Stress Intensity Factor around the Anti-Plane Crack in an Orthotropic Functionally Graded Material

2013 ◽  
Vol 275-277 ◽  
pp. 208-214
Author(s):  
Xue Xia Zhang ◽  
Zhi Xin Hu ◽  
Wen Bin Zhao ◽  
Chan Li
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Shear Modulus ◽  
Functionally Graded Material ◽  
Functionally Graded ◽  
Plane Crack ◽  
Dual Integral Equations ◽  
Dimensionless Stress ◽  
Graded Material

The problem of anti-plane crack in infinity orthotropic functionally graded materials is studied by using of integral transforms-dual integral equations. The shear modulus in the two principal directions of the functionally graded material was assumed to vary proportionately as gradient model of double parameters. And the variation curves of the dimensionless stress intensity factor with the orthogonal parameter and the crack length have been obtained by using the mathematical software .The results shows that stress intensity factor increases with the increasing of and a. It means that stress intensity factor decreases as the shear modulus of perpendicular to crack direction increased.

scholarly journals Evaluation of inclined crack in mixed mode I and II

2021 ◽  
Vol 9 ◽  
Author(s):  
Mohamed Tahar Hannachi ◽  
◽  
Mohamed Bradji ◽  
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Mixed Mode ◽  
Critical Energy ◽  
Mode I ◽  
Inclined Crack ◽  
Ductile Rupture ◽  
Treated Steel ◽  
Mode Of Failure

In this work,we tented to study the mixed mode of failure with two angles of inclination, of a treated steel, for that we tried to determine the parameters of failure as the stress intensity factor, tenacity and the critical energy in mixed mode of a rupture and see the criterion of rupture and seeing the effect of the angles evolution applied for all parameters. of in our close there is a fragile and less ductile rupture.

Dimensionless Stress Intensity Factors of an Annular Notched Shaft

2011 ◽  
Vol 488-489 ◽  
pp. 174-177
Author(s):  
Bo Chen ◽  
You Tang Li
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Field ◽  
Displacement Field ◽  
Stress Concentrator ◽  
Intensity Factors ◽  
Blunt Crack ◽  
Dimensionless Stress ◽  
Tip Radius

The tip radius ρ, depth t and field angle α of notch and the geometrical sizes a and b of shaft are looked as descriptive parameters in the annular notched shaft. Taken the crack, blunt crack and notch as breach, the stress field and displacement field near the tip of breach which serve dimensionless factor fα(a/b) as descriptive parameter are obtained. The effects of parameters ρ, t and α to fα(a/b) are analyzed. The connections between stress intensity factor of crack and stress concentrator factor of notch, between sharp V-notch and crack, between V-notch and U-notch have been founded.

Effect of Stress Distribution on Fatigue Life of Tubular Joints in Offshore Engineering

2007 ◽  
Vol 348-349 ◽  
pp. 897-900
Author(s):  
Yong Bo Shao
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Life ◽  
Stress Intensity ◽  
Stress Distribution ◽  
Intensity Factor ◽  
Failure Process ◽  
Tubular Joints ◽  
Offshore Engineering ◽  
Weld Toe ◽  
Tubular Joint

In the assessment of fatigue life of tubular joints in offshore engineering, hot spot stress range, in conventional method, is frequently used to predict the number of cycles that a tubular joint can sustain before failure from corresponding S-N curves. This method only considers the effect of the peak stress at the weld toe on the fatigue life of a tubular joint, but ignores that of the stress distribution along the weld toe. The effect of the stress distribution along the weld toe on the fatigue life of tubular joints can be evaluated indirectly by analyzing a fracture mechanics parameter, namely stress intensity factor. The stress intensity factor values of the surface cracks in the fatigue failure process for tubular joints subjected to different loading types, thus causing the difference of the stress distributions along the weld toe, are investigated from both numerical analysis and experimental measurement. The results show that the stress distribution along the weld toe has remarkable effect on the fatigue life of tubular joints.

scholarly journals Numerical Simulation of the Influence of Width of a Prefabricated Crack on the Dimensionless Stress Intensity Factor of Notched Semi-Circular Bend Specimens

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Sheng Zhang ◽  
Longfei Wang ◽  
Mingzhong Gao
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Width ◽  
Linear Increase ◽  
Maximum Relative Error ◽  
Dimensionless Stress ◽  
Relative Errors ◽  
New Formula ◽  
Abaqus Software

To analyze the effect of the width of a prefabricated crack on the dimensionless stress intensity factor of notched semi-circular bend (NSCB) specimens, ABAQUS software was employed to perform numerical calibration of the crack tip stress intensity factor for the width of prefabricated cracks in the range of 0.0∼2.0 mm. The relative errors of the dimensionless stress intensity factor for different widths of prefabricated cracks were analyzed. The results indicate that the dimensionless stress intensity factor shows an approximate linear increase as the width of the prefabricated crack increases. The longer is the length of the prefabricated crack, the “faster” is the increase in speed. The effect of the dimensionless support spacing on the increase in the speed of the dimensionless stress intensity factor due to the increase in crack width is minimal. When the prefabricated crack width is 2.0 mm, the maximum relative error of the dimensionless stress intensity factor is 4.325%. The new formula for the dimensionless stress intensity factor that eliminates the influence of the width of a prefabricated crack is given, which provides a theoretical basis for the more accurate fracture toughness value measured using an NSCB specimen.

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