scholarly journals Discussion: “A Modified Strain-Energy Density Criterion Applied to Crack Propagation” (Theocaris, P. S., and Andrianopoulos, N. P., 1982, ASME J. Appl. Mech., 49, pp. 81–86)

1982 ◽  
Vol 49 (3) ◽  
pp. 678-679 ◽  
Author(s):  
G. C. Sih ◽  
E. E. Gdoutos
Keyword(s):  
Energy Density ◽  
Crack Propagation ◽  
Strain Energy Density ◽  
Strain Energy

Fatigue crack propagation prediction of a pressure vessel mild steel based on a strain energy density model

2017 ◽  
Author(s):  
P. J. Huffman ◽  
J. Ferreira ◽  
J.A.F.O. Correia ◽  
A.M.P. De Jesus ◽  
G. Lesiuk ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Energy Density ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Pressure Vessel ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Propagation Model ◽  
Crack Growth Rates

Fatigue crack growth (FCG) rates have traditionally been formulated from fracture mechanics, whereas fatigue crack initiation has been empirically described using stress-life or strain-life methods. More recently, there has been efforts towards the use of the local stress-strain and similitude concepts to formulate fatigue crack growth rates. A new model has been developed which derives stress-life, strain-life and fatigue crack growth rates from strain energy density concepts. This new model has the advantage to predict an intrinsic stress ratio effect of the form ?ar=(?amp)?·(?max )(1-?), which is dependent on the cyclic stress-strain behaviour of the material. This new fatigue crack propagation model was proposed by Huffman based on Walkerlike strain-life relation. This model is applied to FCG data available for the P355NL1 pressure vessel steel. A comparison of the experimental results and the Huffman crack propagation model is made.

scholarly journals Experimental and FE Modeling of Mixed-Mode Crack Initiation Angle in High Density Polyethylene

2018 ◽  
Author(s):  
Abdelwahab Zerrouki ◽  
Abdelkader Boulenouar ◽  
Mohamed Mazari ◽  
Mohamed Benguediab
Keyword(s):  
Numerical Analysis ◽  
Energy Density ◽  
Crack Propagation ◽  
High Density Polyethylene ◽  
Strain Energy Density ◽  
Mixed Mode ◽  
Strain Energy ◽  
Propagation Direction ◽  
Crack Propagation Direction ◽  
Loading Direction

In this paper, an experimental and a numerical analysis were carried out using High density polyethylene (HDPE). Sheets with an initial central crack (CCT specimens) inclined with a given angle are investigated and compared to the loading direction. The kinking angle is experimentally predicted and numerically evaluated under mixed mode (I+II), as a function of the strain energy density (SED) around the crack-tip, using the Ansys Parametric Design Language (APDL).According to the experimental observations and numerical analysis, the plan of crack propagation is perpendicular to the loading direction. Moreover, as suggested by Sih in the framework of linear elastic fracture mechanics (LEFM), the minimum values Sminof the factor S are reached at the points corresponding to the crack propagation direction. These results suggest that the concept of the strain energy- density factor can be used as an indicator of the crack propagation direction.

scholarly journals Crack Growth Direction in Mixed Mode Loading: A Strain Energy Density Approach

2018 ◽  
Vol 6 (4) ◽  
Author(s):  
Tawakol Ahmed Enab ◽  
Hasnaa W. Taha ◽  
Mohamed A. N. Shabara ◽  
Ahmed M. Galal
Keyword(s):  
Finite Element ◽  
Energy Density ◽  
Crack Propagation ◽  
Crack Growth ◽  
Strain Energy Density ◽  
Mixed Mode ◽  
Strain Energy ◽  
Average Deviation ◽  
Finite Element Program ◽  
Linear Elastic

The crack growth in metallic materials using fast and reliable simulations of 2-D and linear elastic finite element models is investigated. The effect of the stress intensity factor in mode I and II (KI, KII) on the fracture behavior of stainless steel and the associated strain energy density factor in mixed mode crack propagation were studied numerically to determine crack propagation angle θ in linear elastic fracture investigation. In order to implement the determination of the crack propagation direction using the strain energy density criterion S, the numerical finite element program ANSYS was used. ANSYS APDL macros were developed to generate the geometry, material properties, boundary conditions and mesh size of the model for the conducted analyses. To demonstrate the capability of crack propagation trajectories using the proposed method under mixed mode situation, an edge crack specimen was considered with initial crack having the same length but at different inclination angles under a uniaxial tension load. Results obtained from the developed models had a good agreement (average deviation of 4.63%) with the results available in the literatures.

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