Fatigue crack propagation within Al-Cu-Mg single crystals based on crystal plasticity and XFEM combined with cohesive zone model

In this study we focus on the effect of hydrogen gas on the cracking resistance of metals. The main objective is to predict the fatigue crack propagation rates in the presence of hydrogen. For this purpose, a Cohesive Zone Model (CZM) dedicated to cracking under monotonic as well as cyclic loadings has been implemented in the ABAQUS finite element code. A specific traction-separation law, adapted to describe the gradual degradation of the cohesive stresses under cyclic loading, and sensitive to the presence of hydrogen is formulated. The coupling between mechanical behaviour and diffusion of hydrogen can be modelled using a coupled temperature - displacement calculation available in ABAQUS. The simulations are compared with fatigue crack propagation tests performed on a 15-5PH martensitic stainless steel. They show that while the proposed model is able to predict a lower resistance to cracking in presence of hydrogen, at this stage it cannot fully account for the detrimental effect induced by high pressure of gaseous hydrogen.

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Influence of hydrogen coverage on the parameters of a cohesive zone model dedicated to fatigue crack propagation

Procedia Engineering ◽

10.1016/j.proeng.2011.04.443 ◽

2011 ◽

Vol 10 ◽

pp. 2657-2662 ◽

Cited By ~ 9

Author(s):

C. Moriconi ◽

G. Henaff ◽

D. Halm

Keyword(s):

Fatigue Crack ◽

Crack Propagation ◽

Fatigue Crack Propagation ◽

Cohesive Zone ◽

Cohesive Zone Model ◽

Zone Model

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Numerical Simulation of Fatigue Crack Growth Rate and Crack Retardation due to an Overload Using a Cohesive Zone Model

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.891-892.777 ◽

2014 ◽

Vol 891-892 ◽

pp. 777-783 ◽

Cited By ~ 2

Author(s):

Sarmediran Silitonga ◽

Johan Maljaars ◽

Frans Soetens ◽

Hubertus H. Snijder

Keyword(s):

Finite Element ◽

Fatigue Crack ◽

Fatigue Crack Growth ◽

Crack Propagation ◽

Crack Growth ◽

Cohesive Zone ◽

Cohesive Zone Model ◽

Crack Tip ◽

Zone Model ◽

Cohesive Elements

In this work, a numerical method is pursued based on a cohesive zone model (CZM). The method is aimed at simulating fatigue crack growth as well as crack growth retardation due to an overload. In this cohesive zone model, the degradation of the material strength is represented by a variation of the cohesive traction with respect to separation of the cohesive surfaces. Simulation of crack propagation under cyclic loads is implemented by introducing a damage mechanism into the cohesive zone. Crack propagation is represented in the process zone (cohesive zone in front of crack-tip) by deterioration of the cohesive strength due to damage development in the cohesive element. Damage accumulation during loading is based on the displacements in the cohesive zone. A finite element model of a compact tension (CT) specimen subjected to a constant amplitude loading with an overload is developed. The cohesive elements are placed in front of the crack-tip along a pre-defined crack path. The simulation is performed in the finite element code Abaqus. The cohesive elements behavior is described using the user element subroutine UEL. The new damage evolution function used in this work provides a good agreement between simulation results and experimental data.

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Finite Element Analysis of the Effect of Residual Stress on Mechanical Behavior of Welded Plates

Materials Science Forum ◽

10.4028/www.scientific.net/msf.580-582.605 ◽

2008 ◽

Vol 580-582 ◽

pp. 605-608

Author(s):

Byeong Choon Goo ◽

Seung Yong Yang

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Fatigue Crack ◽

Residual Stresses ◽

Crack Propagation ◽

Mechanical Behavior ◽

Fatigue Crack Propagation ◽

Cohesive Zone Model ◽

Zone Model ◽

Element Analysis

Residual stresses play an important role in the mechanical behavior of steels and welded structures. To examine the effect of residual stresses on tensile behavior and fatigue, residual stresses in the specimens were generated by welding. Experimental stress-strain curves of the specimens with/without residual stresses were obtained and compared to simulated curves obtained by the finite element analysis. The two results are in a good agreement. Finally, to study the relaxation of the residual stresses during fatigue crack propagation, we carried out fatigue crack propagation analysis by a 3-D cohesive zone model. Initial welding residual stresses decrease as the number of cycles increases.

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