Numerical calculation of crack driving force using the configurational force concept for elastic–plastic rail cracks

2020 ◽  
Vol 13 (1) ◽  
pp. 45-64
Author(s):  
Reza Babnadi ◽  
Parisa Hosseini Tehrani
Keyword(s):  
Numerical Calculation ◽  
Driving Force ◽  
Configurational Force ◽  
Crack Driving Force ◽  
Elastic Plastic ◽  
Force Concept

Crack Growth Tendency of Surface Shear Cracks in Rolling Sliding Contact

2013 ◽  
Vol 592-593 ◽  
pp. 250-253
Author(s):  
Werner Daves ◽  
Wei Ping Yao ◽  
Stephan Scheriau
Keyword(s):  
Driving Force ◽  
Kinematic Hardening ◽  
Sliding Contact ◽  
Crack Model ◽  
Shear Cracks ◽  
Configurational Force ◽  
Inclined Crack ◽  
Surface Shear ◽  
Crack Driving Force ◽  
Force Concept

Surface cracks arising during rolling sliding contact of a wheel and a rail are investigated. A two-dimensional crack model is proposed which calculates the crack driving force using the configurational force concept. The numerical applicability of the configurational force concept for surface shear cracks under cyclic contact loading is discussed and compared to the J-integral concept. A single inclined crack in a rail loaded by an accelerated wheel is investigated. The material of the rail is described by a cyclic plastic kinematic hardening model. The evolution of the crack driving force during several cycles is investigated.

The Configurational Force Concept in Elastic-Plastic Fracture Mechanics−Instructive Examples

2009 ◽  
Vol 417-418 ◽  
pp. 297-300 ◽  
Author(s):  
R. Schöngrundner ◽  
Otmar Kolednik ◽  
Franz Dieter Fischer
Keyword(s):  
Driving Force ◽  
Plastic Material ◽  
Shielding Effect ◽  
Integral Approach ◽  
J Integral ◽  
Configurational Force ◽  
Crack Driving Force ◽  
Elastic Plastic ◽  
Elastic Plastic Material ◽  
Elastic Plastic Materials

This paper deals with the determination of the crack driving force in elastic-plastic materials and its correlation with the J-Integral approach. In a real elastic-plastic material, the conventional J-integral cannot describe the crack driving force. This problem has been solved in Simha et al. [1], where the configurational force approach was used to evaluate in a new way the J-integral under incremental plasticity conditions. The crack driving force in a homogeneous elastic-plastic material, Jtip, is given by the sum of the nominally applied far-field crack driving force, Jfar, and the plasticity influence term, Cp, which accounts for the shielding or anti-shielding effect of plasticity. In this study, the incremental plasticity J-integral and the crack driving force are considered for a stationary and a growing crack.

J-integral and crack driving force in elastic–plastic materials

2008 ◽  
Vol 56 (9) ◽  
pp. 2876-2895 ◽  
Author(s):  
N SIMHA ◽  
F FISCHER ◽  
G SHAN ◽  
C CHEN ◽  
O KOLEDNIK
Keyword(s):  
Driving Force ◽  
J Integral ◽  
Crack Driving Force ◽  
Elastic Plastic ◽  
Plastic Materials ◽  
Elastic Plastic Materials

Elastic–plastic crack driving force for tubular X-joints with mismatched welds

2005 ◽  
Vol 27 (9) ◽  
pp. 1419-1434 ◽  
Author(s):  
X. Qian ◽  
Robert H. Dodds ◽  
Y.S. Choo
Keyword(s):  
Driving Force ◽  
Crack Driving Force ◽  
Elastic Plastic

Assessment of Fully Plastic J and C*-Integral Solutions for Application to Elastic-Plastic Fracture and Creep Crack Growth

1993 ◽  
Vol 115 (3) ◽  
pp. 228-234 ◽  
Author(s):  
D. R. Lee ◽  
J. M. Bloom
Keyword(s):  
Finite Element ◽  
Crack Growth ◽  
Driving Force ◽  
Creep Crack Growth ◽  
J Integral ◽  
Finite Element Program ◽  
Hardening Material ◽  
Crack Driving Force ◽  
Elastic Plastic ◽  
Creep Crack

A critical part of the assessment of defects in power plant components, both fossil and nuclear, is the knowledge of the crack driving force (K1, J, or C*). While the determination of the crack driving force is possible using finite element analyses, crack growth analyses using finite element methods can be expensive. Based on work by Il’yushin, it has been shown that for a power law hardening material, the fully plastic portion of the J-integral (or the C*-integral) is directly related to an h1 calibration function. The value of h1 is a function of the geometry and hardening exponent. The finite element program ABAQUS was used to evaluate the fully plastic J-integral and determine the h1 functions for various geometries. The Ramberg-Osgood deformation theory plasticity model, which may be used with the J-integral evaluation capability, allows the evaluation of fully plastic J solutions. Once it was established that the grid used to generate the h1 functions was adequate (based on the more recent work of Shih and Goan), additional runs were made of other configurations given in the EPRI Elastic-Plastic Fracture Handbook. Differences as great as 55 percent were found when compared to results given in the Handbook (single-edge crack plate under tension and plane stress with a/b = 0.5). Effects of errors in h1 on predicted failure load and creep crack growth are discussed.

Elastic-Plastic Analyses of Surface Flaws in a Reactor Vessel

1984 ◽  
Vol 106 (3) ◽  
pp. 247-254 ◽  
Author(s):  
W. W. Wilkening ◽  
H. G. deLorenzi ◽  
M. Barishpolsky
Keyword(s):  
Internal Pressure ◽  
Crack Front ◽  
Driving Force ◽  
Maximum Depth ◽  
Crack Driving Force ◽  
Elastic Plastic ◽  
Single Curve ◽  
Surface Flaws ◽  
Virtual Crack Extension Method ◽  
Design Pressure

Elastic-plastic analyses have been performed for the ASME Maximum Postulated Flaw and for three other semielliptical surface flaws in the beltline region of a nuclear reactor pressure vessel, with internal radius to thickness ratio, R/t, equal to 10, using nonlinear 3-D finite element methods based upon the deformation theory of plasticity. Three of the flaws had a maximum depth, a, equal to t/4, with aspect ratios, 2c/a, equal to 6 (the ASME Maximum Postulated Flaw), 4 and 3, respectively, where 2c is the surface length of the flaw. These flaws were analyzed for internal pressure varying from one to three times the design pressure, which is well into the fully plastic regime for the uncracked vessel. The fourth flaw had an aspect ratio, 2c/a, equal to 6, and its maximum depth, a, was equal to 3t/4. This deep flaw was analyzed for internal pressure varying from 60 percent of design pressure to twice the design pressure. The crack driving force was calculated as the energy release rate, J, using the virtual crack extension method. The results illustrate that, at the design pressure, plasticity near the crack front is so limited for the three flaws with a/t = 1/4 that an elastic analysis is adequate. At higher pressures, however, the elastic analyses become increasingly nonconservative and would grossly underestimate the severity of the flaws. The variation of both J and crack opening displacement, COD, along the crack front were studied. Generally, the values at the maximum depth location, denoted J* and COD*, respectively, were the maximum values, with minimum values occurring at the free surface. A simple normalization scheme was found which collapsed the J* versus pressure results for the four semielliptical flaws into a single curve. A similar normalization also collapsed the COD* versus pressure results for the four flaws into a single curve. In addition, a unique linear relationship between J* and COD* was found to apply for the results from all four sets of analyses for internal pressure levels up to at least 2.5 times the design pressure. The analyses therefore demonstrate that J and COD are equivalent measures of the crack driving force, and further demonstrate that a realistic 3-D elastic-plastic analysis is needed to properly assess the severity of surface flaws.

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