Finite Element Analysis of the Effects of Thermally Grown Oxide Thickness and Interface Asperity on the Cracking Behavior Between the Thermally Grown Oxide and the Bond Coat

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Jishen Jiang ◽  
Bingqian Xu ◽  
Weizhe Wang ◽  
Richard Amankwa Adjei ◽  
Xiaofeng Zhao ◽  
...  
Keyword(s):  
Finite Element ◽  
Bond Coat ◽  
Cohesive Zone Model ◽  
Interfacial Crack ◽  
Maximum Tensile Stress ◽  
Thermally Grown Oxide ◽  
Zone Model ◽  
Element Analysis ◽  
Cracking Behavior ◽  
Thermally Grown

Finite element simulations based on an interface cohesive zone model (CZM) have been developed to mimic the interfacial cracking behavior between the α−Al2O3 thermally grown oxide (TGO) and the aluminum-rich Pt–Al metallic bond coat (BC) during cooling from high temperature to ambient temperature. A two-dimensional half-periodic sinusoidal geometry corresponding to interface undulation is modeled. The effects of TGO thickness and interface asperity on the stress distribution and the cracking behavior are examined by parametric studies. The simulation results show that cracking behavior due to residual stress and interface asperity during cooling process leads to stress redistribution around the rough interface. The TGO thickness has strong influence on the maximum tensile stress of TGO and the interfacial crack development. For the sinusoidal asperities, there exists a critical amplitude above which the interfacial cracking is energetically favored. For any specific TGO thickness, crack initiation is dominated by the amplitude while crack propagation is restricted to the combine actions of the wavelength and the amplitude of the sinusoidal asperity.

FE Analysis of the Effects of TGO Thickness and Interface Asperity on the Cracking Behavior Between the TGO and the Bond Coat

2016 ◽  
Author(s):  
Jishen Jiang ◽  
Bingqian Xu ◽  
Weizhe Wang ◽  
Richard Amankwa Adjei ◽  
Xiaofeng Zhao ◽  
...  
Keyword(s):  
Bond Coat ◽  
Cohesive Zone Model ◽  
Interfacial Crack ◽  
Maximum Tensile Stress ◽  
Thermally Grown Oxide ◽  
Zone Model ◽  
Cracking Behavior ◽  
Metallic Bond ◽  
Parametric Studies ◽  
Α Al2o3

Finite element simulations based on an interface cohesive zone model (CZM) have been developed to mimic the interfacial cracking behavior between the α-Al2O3 thermally grown oxide (TGO) and the aluminum rich Pt–Al metallic bond coat (BC) during cooling from high temperature to ambient temperature. A two dimensional half-periodic sinusoidal geometry corresponding to interface undulation is modelled. The effects of TGO thickness and interface asperity on the stress distribution and the cracking behavior are examined by parametric studies. The simulation results show that cracking behavior due to residual stress and interface asperity during cooling process leads to stress redistribution around the rough interface. The TGO thickness has strong influence on the maximum tensile stress of TGO and the interfacial crack development. For the sinusoidal asperities, there exist a critical amplitude above which interfacial cracking is energetically favored. For any specific TGO thickness, crack initiation is dominated by the amplitude while crack propagation is restricted to the combine actions of the wavelength and the amplitude of the sinusoidal asperity.

Progressive failure analysis of scarf-repaired composite laminate based on damage constitutive model

2016 ◽  
Vol 233 (2) ◽  
pp. 180-188 ◽  
Author(s):  
Qiuyi Shen ◽  
Zhenghao Zhu ◽  
Yi Liu
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Composite Laminate ◽  
Damage Mechanics ◽  
Cohesive Zone Model ◽  
Load Capacity ◽  
Three Dimensional ◽  
Zone Model ◽  
State Variables ◽  
Element Analysis

A three-dimensional finite element model for scarf-repaired composite laminate was established on continuum damage model to predict the load capacity under tensile loading. The mixed-mode cohesive zone model was adopted to the debonding behavior analysis of adhesive. Damage condition and failure of laminates and adhesive were subsequently addressed. A three-dimensional bilinear constitutive model was developed for composite materials based on damage mechanics and applied to damage evolution and loading capacity analyses by quantifying damage level through damage state variables. The numerical analyses were implemented with ABAQUS finite element analysis by coding the constitutive model into material subroutine VUMAT. Good agreement between the numerical and experimental results shows the accuracy and adaptability of the model.

Finite Element Analysis for the Effect of Weak Interface on the Ratcheting of Particle Reinforced Composites

2013 ◽  
Vol 785-786 ◽  
pp. 214-219
Author(s):  
Ya Le Yan ◽  
Juan Zhang ◽  
Su Juan Guo
Keyword(s):  
Finite Element ◽  
Cohesive Zone Model ◽  
Experimental Results ◽  
Zone Model ◽  
Matrix Composites ◽  
Weak Interface ◽  
Element Analysis ◽  
Ratcheting Strain ◽  
Element Simulation ◽  
Particulate Reinforced

The deformation behavior of particulate reinforced metal matrix composites (PRMMCs) under monotonic and cyclic loadings was simulated by FEA method. Base on the cohesive zone model, the effect of the interface between particle and matrix was considered. Then, the finite element simulation of the PRMMCs with an ideal interface and weak interface was compared with corresponding experimental results. It is shown that: with a weak interface been considered in the finite element simulations, the resistance of PRMMCs to the ratcheting strain was reduced, which gets more closed to the experimental results.

Stress Distribution in the Vicinity of Thermally Grown Oxide of Thermal Barrier Coatings

2010 ◽  
Vol 160-162 ◽  
pp. 721-725 ◽  
Author(s):  
Xue Ling Fan ◽  
Wen Jun Qin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Thermally Grown Oxide ◽  
Thermal Barrier ◽  
Element Analysis ◽  
Field Development ◽  
The Finite Element Analysis ◽  
Unit Cells ◽  
Thermally Grown

Finite element simulation of stress distribution of thermal barrier coating system (TBCs) is presented. Two dimensional periodic unit cells are used to examine the stress development and critical sites with high potential of cracking during thermal cycling. During cooling, high tensile out-of-plane stresses in the peak of the thermally grown oxide (TGO) are formed, which lead to crack initiation in the vicinity of TGO and the interface. At the same time, high compressive stresses developed in the valley domain. The influence of crack within the top coat in the vicinity of the TGO is also investigated. The finite element analysis shows that crack seriously affects stress field development and the thermal-mechanical behavior of TBCs. Based on the finite element analysis results one can conclude that imperfections and its development should be always considered to be a crucial parameter for TBCs life.

Crack Extensions in Compact Tension Specimens of Hydrided Irradiated Zr-2.5Nb Materials Using Cohesive Zone Model

2017 ◽  
Author(s):  
Shengjia Wu ◽  
Shin-Jang Sung ◽  
Jwo Pan ◽  
Poh-Sang Lam ◽  
Douglas A. Scarth
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cohesive Zone ◽  
Crack Extension ◽  
Cohesive Zone Model ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Zone Model ◽  
Element Analysis ◽  
The Finite Element Analysis

The crack extension in a compact tension specimen of hydrided irradiated Zr-2.5Nb material is investigated by a two-dimensional plane stress finite element analysis. The stress-strain relation of the Zr-2.5Nb material for the finite element analysis is obtained from fitting the experimental tensile stress-strain curve of the irradiated Zr-2.5Nb material without hydrides by a three-dimensional finite element analysis. The calibration of the cohesive zone model with a trapezoidal traction-separation law is based on fitting the load-displacement-crack extension experimental data of a compact tension specimen of hydrided irradiated Zr-2.5Nb material. The general trends of the load-displacement, crack extension-displacement, and load-crack extension curves obtained from the finite element analysis based on the calibrated cohesive zone model are in agreement with the experimental data.

Sign in / Sign up

Export Citation Format

Share Document