A Finite Element Study of Stable Crack Growth Under Plane Stress Conditions: Part II—Influence of Hardening

1987 ◽  
Vol 54 (4) ◽  
pp. 846-853 ◽  
Author(s):  
R. Narasimhan ◽  
A. J. Rosakis ◽  
J. F. Hall
Keyword(s):  
Finite Element ◽  
Crack Growth ◽  
Plane Stress ◽  
Crack Opening ◽  
Stable Crack Growth ◽  
Small Scale ◽  
Opening Displacement ◽  
Element Analysis ◽  
Critical Crack ◽  
Perfectly Plastic

A detailed finite element analysis is performed to model quasi-static crack growth under plane stress, small-scale yielding conditions in elastic-plastic materials characterized by isotropic power law hardening and the Huber-Von Mises yield surface. A nodal release procedure is used to simulate crack extension. Results pertaining to the influence of hardening on the extent of active yielding and the near-tip stress and deformation fields are presented. Clear evidence of an elastic unloading wake following the active plastic zone is found, but no secondary (plastic) reloading along the crack flank is numerically observed for any level of hardening. A ductile crack growth criterion based on the attainment of a critical crack opening displacement at a small microstructural distance behind the tip, is employed to investigate the nature of the J resistance curves under plane stress. In addition, the same criterion is employed to investigate the influence of hardening on the potential for stable crack growth under plane stress. It is found that predictions based on a perfectly plastic model may be unconservative in this respect, which is qualitatively similar to the conclusions reached in antiplane shear and Mode I plane strain.

A Finite Element Study of Stable Crack Growth Under Plane Stress Conditions: Part I—Elastic-Perfectly Plastic Solids

1987 ◽  
Vol 54 (4) ◽  
pp. 838-845 ◽  
Author(s):  
R. Narasimhan ◽  
A. J. Rosakis ◽  
J. F. Hall
Keyword(s):  
Finite Element ◽  
Plastic Zone ◽  
Crack Growth ◽  
Plane Stress ◽  
Stable Crack Growth ◽  
Small Scale ◽  
Finite Element Study ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
Element Study

A detailed finite element study of stable crack growth in elastic-perfectly plastic solids obeying an incremental plasticity theory and the Huber-Von Mises yield criterion is performed under plane stress, small-scale yielding conditions. A nodal release procedure is used to simulate crack extension under continuously increasing external load. It is found that the asymptotic angular extent of the active plastic zone surrounding the moving crack tip is from θ = 0 deg to about θ = 45 deg. Clear evidence of an elastic unloading region following the active plastic zone is found, but no secondary (plastic) reloading is numerically observed. The near-tip angular stress distribution inside the active plastic zone is in good agreement with the variation inside a centered fan, as predicted by a preliminary asymptotic analysis by Rice. It is also observed that the stress components within the plastic zone have a strong radial variation. The nature of the near-tip profile is studied in detail.

Finite Element Analysis of Brittle Cracking due to Single Grit Rotating Scratch

2003 ◽  
Vol 70 (1) ◽  
pp. 147-151 ◽  
Author(s):  
G. Subhash ◽  
W. Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Crack Opening ◽  
Damage Zone ◽  
Depth Of Cut ◽  
Opening Displacement ◽  
Element Analysis ◽  
Critical Crack ◽  
Critical Crack Opening ◽  
Brittle Material Removal

Finite element analysis of single grit rotating scratch on brittle materials was conducted using an “elastic-plastic-cracking” (EPC) model. The brittle material removal mechanism was modeled based on a critical crack-opening displacement criterion. It was found that the tangential and normal force profiles as well as the damage morphology observed in scratch experiments were fully captured by the EPC model. The results revealed that the induced damage zone size increases linearly with a brittleness parameter EY/σf21/3 as well as the maximum depth of cut.

A Finite Element Study of Stable Crack-Growth in Superelastic Shape Memory Alloys

2012 ◽  
Author(s):  
Antonino Parrinello ◽  
Theocharis Baxevanis ◽  
Dimitris Lagoudas ◽  
Austin Cox
Keyword(s):  
Finite Element ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Crack Growth ◽  
Small Strain ◽  
Stable Crack Growth ◽  
Constitutive Law ◽  
Scale Transformation ◽  
Small Scale ◽  
Element Analysis

A finite-element analysis of stable crack growth in superelastic Shape Memory Alloys (SMAs) is carried out for plane strain, mode I loading. The small-scale transformation assumption is employed in the calculations using displacement boundary conditions on a circular region that encloses the stress-induced phase transformation zone. The constitutive law adopts the classical rate-independent small-strain flow theory for the evolution equation of the transformation strains. The crack is assumed to propagate quasi-statically with the energy release rate maintained at a critical value; the analysis is accomplished by means of the Virtual Crack Closure Technique (VCCT). Resistance curves, obtained for a range of thermomechanical parameters, show enhanced fracture toughness.

scholarly journals Fracture toughness and crack growth of brackish ice using chevron-notched specimens

1994 ◽  
Vol 40 (135) ◽  
pp. 415-426
Author(s):  
Lars Stehn
Keyword(s):  
Fracture Toughness ◽  
Crack Growth ◽  
Crack Opening ◽  
Initial Crack ◽  
Effect Study ◽  
Small Scale ◽  
Opening Displacement ◽  
Critical Crack ◽  
Experimental Calibration ◽  
Brackish Ice

AbstractField-test equipment called FIFT (a Field Instrument for Fracture toughness Tests on ice) was used in both field and laboratory fracture-toughness tests on brackish sea ice from the Gulf of Bothnia. An experimental calibration was performed and a compliance expression was then derived for the Short Rod Chevron Notched (SRCN) specimen. Using the SRCN configuration, for which the initial crack growth is shown to be stable, and measured load-point displacements, preliminary crack-growth velocities are found. The obtained estimated crack velocity is, on average,ȧe= 20 ms−1, albeit with a large standard deviation. The results indicate that critical crack (crack-jumping) growth occurs. The apparent fracture toughness,KQ, was found to have a pronounced dependency on porosity in the form of brine volume. The results obtained are derived from a linearly elastic fracture mechanics (LEFM) theory. Consequently, the tests were designed to satisfy small-scale yielding requirements in terms of notch sensitivity and brittleness. The linearity of the load vs crack-opening displacement curves together with a size-effect study, showing that the specimen is notch-sensitive for grain-sizes ranging from 1.6 to nearly 100 mm, indicate that LEFM could be applicable.

Crack Growth Resistance of Ceramic Composite

1992 ◽  
Vol 287 ◽  
Author(s):  
Seijiro Hayashi ◽  
H. Baba ◽  
A. Suzuki
Keyword(s):  
Crack Growth ◽  
Fracture Process ◽  
Ceramic Composite ◽  
Fracture Process Zone ◽  
Process Zone ◽  
Crack Opening ◽  
Stable Crack Growth ◽  
Beam Specimen ◽  
Opening Displacement ◽  
Element Analysis

ABSTRACTFracture process zone in SiCw/Si3N4 ceramic composite was studied by a hybrid experimental-numerical analysis employing moire interferometry and finite element analysis. A chevron-notched, wedge-loaded double cantilever beam specimen was used to obtain a stable crack growth. The relation between crack closure stress and crack opening displacement which govern fracture process zone was obtained.

scholarly journals Fracture toughness and crack growth of brackish ice using chevron-notched specimens

1994 ◽  
Vol 40 (135) ◽  
pp. 415-426 ◽  
Author(s):  
Lars Stehn
Keyword(s):  
Fracture Toughness ◽  
Crack Growth ◽  
Crack Opening ◽  
Initial Crack ◽  
Effect Study ◽  
Small Scale ◽  
Opening Displacement ◽  
Critical Crack ◽  
Experimental Calibration ◽  
Brackish Ice

AbstractField-test equipment called FIFT (a Field Instrument for Fracture toughness Tests on ice) was used in both field and laboratory fracture-toughness tests on brackish sea ice from the Gulf of Bothnia. An experimental calibration was performed and a compliance expression was then derived for the Short Rod Chevron Notched (SRCN) specimen. Using the SRCN configuration, for which the initial crack growth is shown to be stable, and measured load-point displacements, preliminary crack-growth velocities are found. The obtained estimated crack velocity is, on average,ȧe= 20 ms−1, albeit with a large standard deviation. The results indicate that critical crack (crack-jumping) growth occurs. The apparent fracture toughness,KQ, was found to have a pronounced dependency on porosity in the form of brine volume. The results obtained are derived from a linearly elastic fracture mechanics (LEFM) theory. Consequently, the tests were designed to satisfy small-scale yielding requirements in terms of notch sensitivity and brittleness. The linearity of the load vs crack-opening displacement curves together with a size-effect study, showing that the specimen is notch-sensitive for grain-sizes ranging from 1.6 to nearly 100 mm, indicate that LEFM could be applicable.

The Prediction of Fatigue Crack Opening Behavior Using Cyclic Crack Tip Opening Displacement by Finite Element Analysis

2006 ◽  
Vol 324-325 ◽  
pp. 295-298 ◽  
Author(s):  
Hyeon Chang Choi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Crack ◽  
Crack Opening ◽  
Crack Tip ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Element Analysis ◽  
Element Size ◽  
Crack Tip Opening

An elastic-plastic finite element analysis (FEA) is performed to examine the opening behavior of fatigue crack, where the contact elements are used in the mesh of the crack tip area. The relationship between fatigue crack opening behavior and cyclic crack tip opening displacement was studied in the previous study. In this paper, we investigate the effect of the element size when predict fatigue crack opening behavior using the cyclic crack tip opening displacement obtained from FEA. The cyclic crack tip opening displacement is well related to fatigue crack opening behavior.

J-Integral and Crack Opening Displacement as Crack Initiation Criteria in Rubber

1986 ◽  
Vol 59 (5) ◽  
pp. 787-799 ◽  
Author(s):  
R. F. Lee ◽  
J. A. Donovan
Keyword(s):  
Crack Initiation ◽  
Carbon Black ◽  
Crack Growth ◽  
Crack Opening ◽  
Crack Tip ◽  
J Integral ◽  
Carbon Black Content ◽  
Opening Displacement ◽  
Critical Crack ◽  
Growth Initiation

Abstract 1. Evaluation of ∫σdδ where σ is the net section stress and δ is the deformed crack tip diameter requires only one specimen to characterize the initiation of crack growth in unfilled and carbon-black-filled NR. 2. ∫σdδ is equal to one half of the J-integral for crack growth initiation, which is identical to the Thomas tearing energy for a blunt notch. 3. The critical J-integral for crack initiation increases linearly with carbon black content. 4. The critical crack tip radius for crack initiation is independent of carbon black content, and the required crack tip region stress increases linearly with carbon black content.

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