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.

scholarly journals Configurational forces in cyclic metal plasticity

2019 ◽  
Vol 300 ◽  
pp. 08009
Author(s):  
Aris Tsakmakis ◽  
Michael Vormwald
Keyword(s):  
Driving Force ◽  
Plastic Material ◽  
Kinematic Hardening ◽  
Yield Function ◽  
Configurational Forces ◽  
Isotropic Hardening ◽  
Crack Driving Force ◽  
Metal Plasticity ◽  
Elastic Plastic ◽  
Von Mises

The configurational force concept is known to describe adequately the crack driving force in linear fracture mechanics. It seems to represent the crack driving force also for the case of elastic-plastic material properties. The latter has been recognized on the basis of thermodynamical considerations. In metal plasticity, real materials exhibit hardening effects when sufficiently large loads are applied. Von Mises yield function with isotropic and kinematic hardening is a common assumption in many models. Kinematic and isotropic hardening turn out to be very important whenever cyclic loading histories are applied. This holds equally regardless of whether the induced deformations are homogeneous or non-homogeneous. The aim of the present paper is to discuss the effect of nonlinear isotropic and kinematic hardening on the response of the configurational forces and related parameters in elastic-plastic fracture problems.

Cracks Loaded by Rolling Contact - Influence of Plasticity around the Crack

2016 ◽  
Vol 258 ◽  
pp. 221-224 ◽  
Author(s):  
Werner Daves ◽  
Michal Kráčalík
Keyword(s):  
Finite Elements ◽  
Driving Force ◽  
Driving Forces ◽  
Crack Tip ◽  
Rolling Contact ◽  
Shear Cracks ◽  
Sliding Contacts ◽  
Crack Driving Force ◽  
Non Linear ◽  
The Common

For the description of cracks in rolling/sliding contacts many overlapping interactions has to be regarded and most of them are non-linear phenomena. This paper emphasis the aspect of plasticity around cyclically loaded shear cracks which is omitted very often in the common literature. It is shown that this plasticity can be calculated and regarded in computed crack driving forces; however, the problem is not solved after doing this. It is a first estimate only to regard the crack driving force calculated in the finite elements surrounding the crack tip as a relevant measure.

scholarly journals Driving forces on dislocations: finite element analysis in the context of the non-singular dislocation theory

2021 ◽  
Author(s):  
Xiandong Zhou ◽  
Christoph Reimuth ◽  
Peter Stein ◽  
Bai-Xiang Xu
Keyword(s):  
Finite Element ◽  
Dislocation Loop ◽  
Driving Force ◽  
Complex Geometry ◽  
Driving Forces ◽  
Singular Solutions ◽  
Dislocation Model ◽  
Configurational Force ◽  
Element Analysis ◽  
Dislocation Configuration

AbstractThis work presents a regularized eigenstrain formulation around the slip plane of dislocations and the resultant non-singular solutions for various dislocation configurations. Moreover, we derive the generalized Eshelby stress tensor of the configurational force theory in the context of the proposed dislocation model. Based on the non-singular finite element solutions and the generalized configurational force formulation, we calculate the driving force on dislocations of various configurations, including single edge/screw dislocation, dislocation loop, interaction between a vacancy dislocation loop and an edge dislocation, as well as a dislocation cluster. The non-singular solutions and the driving force results are well benchmarked for different cases. The proposed formulation and the numerical scheme can be applied to any general dislocation configuration with complex geometry and loading conditions.

Crack Driving Force in Anisotropic Media due to Non-Elastic Deformation

2004 ◽  
Vol 261-263 ◽  
pp. 75-80
Author(s):  
G.H. Nie ◽  
H. Xu
Keyword(s):  
Elastic Deformation ◽  
Driving Force ◽  
Strain Energy ◽  
Elastic Stress ◽  
Complex Function ◽  
Crack Driving Force ◽  
Special Cases ◽  
Degree Of Anisotropy ◽  
Minimum Strain Energy ◽  
Orthotropic Media

In this paper elastic stress field in an elliptic inhomogeneity embedded in orthotropic media due to non-elastic deformation is determined by the complex function method and the principle of minimum strain energy. Two complex parameters are expressed in a general form, which covers all characterizations of the degree of anisotropy for any ideal orthotropic elastic body. The stress acting on the long side of ellipse can be considered as a crack driving force and applied in failure and fatigue analysis of composites. For some special cases, the resulting solutions will reduce to the known results.

Multi-Tier Tensile Strain Models for Strain-Based Design: Part 2 — Development and Formulation of Tensile Strain Capacity Models

2012 ◽  
Author(s):  
Ming Liu ◽  
Yong-Yi Wang ◽  
Yaxin Song ◽  
David Horsley ◽  
Steve Nanney
Keyword(s):  
Driving Force ◽  
Tensile Strain ◽  
Weld Strength ◽  
Experiment Data ◽  
Pipe Wall Thickness ◽  
Crack Driving Force ◽  
Strain Capacity ◽  
Welding Processes ◽  
Tensile Strain Capacity

This is the second paper in a three-paper series related to the development of tensile strain models. The fundamental basis of the models [1] and evaluation of the models against experiment data [2] are presented in two companion papers. This paper presents the structure and formulation of the models. The philosophy and development of the multi-tier tensile strain models are described. The tensile strain models are applicable for linepipe grades from X65 to X100 and two welding processes, i.e., mechanized GMAW and FCAW/SMAW. The tensile strain capacity (TSC) is given as a function of key material properties and weld and flaw geometric parameters, including pipe wall thickness, girth weld high-low misalignment, pipe strain hardening (Y/T ratio), weld strength mismatch, girth weld flaw size, toughness, and internal pressure. Two essential parts of the tensile strain models are the crack driving force and material’s toughness. This paper covers principally the crack driving force. The significance and determination of material’s toughness are covered in the companion papers [1,2].

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