Simulation of Fatigue Crack Propagation Process after Overload Based on Cohesive Zone Model

2019 ◽  
Author(s):  
Ruijin Zhang ◽  
Binbin Hu ◽  
Lida Xu ◽  
Bin Cao
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Zone Model ◽  
Propagation Process ◽  
Crack Propagation Process

scholarly journals Crack Propagation of SS304/BNi-2 Brazed Joints: Experiments and Numerical Simulations

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1031 ◽  
Author(s):  
Zhou ◽  
Jiang ◽  
Tan ◽  
Shi ◽  
Yang
Keyword(s):  
Crack Propagation ◽  
Numerical Simulations ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Zone Model ◽  
Propagation Process ◽  
Whole Process ◽  
Crack Propagation Process ◽  
Brazed Joints ◽  
Brazed Joint

The strength of brazed joints is of great significance for plate-fin heat exchangers. Although a lot of research on the strength of brazed joints has been carried out, few studies have focused on the whole process of the crack propagation of brazed joints under loading, and no accurate simulation methods have been published. In this paper, the crack propagation of SS304/BNi-2 brazed joints was investigated by both experiments and numerical simulations. The cohesive zone model (CZM) was applied to simulate the crack propagation. The cohesive energy was obtained by the T-type brazed joint peeling experiments. The cohesive strength was determined as 30 MPa by comparing the load–displacement curves from the simulations and experiments. The results showed that the crack propagation process predicted by the CZM was consistent with the experimental results. Furthermore, with the increase of displacement applied on the specimen, the rate of crack propagation of the brazed joints was high at the beginning, and then gradually slowed down in the later stages. Under displacement-controlled conditions, increasing the thickness and the yield strength of the base metal could delay the crack initiation, but it would increase the crack growth rate once the crack was initiated.

A Cohesive Zone Model to Simulate Fatigue Crack Propagation under High Pressure Gaseous Hydrogen

2014 ◽  
Vol 891-892 ◽  
pp. 765-770
Author(s):  
Giovambattista Bilotta ◽  
Clara Moriconi ◽  
Gilbert Hénaff ◽  
Mandana Arzaghi ◽  
Damien Halm
Keyword(s):  
High Pressure ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Hydrogen Gas ◽  
Gaseous Hydrogen ◽  
Zone Model ◽  
Cohesive Stresses

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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