Interface crack of two dissimilar bonded functionally graded strips with arbitrary distributed properties under plane deformations

2012 ◽  
Vol 54 (1) ◽  
pp. 287-293 ◽  
Author(s):  
Zhanqi Cheng ◽  
Danying Gao ◽  
Zheng Zhong
Keyword(s):  
Interface Crack ◽  
Functionally Graded ◽  
Plane Deformations

Analysis on Functionally Graded Material Coating Interface Crack

2012 ◽  
Vol 602-604 ◽  
pp. 1596-1599
Author(s):  
Bo He ◽  
Chang Qing Sun
Keyword(s):  
Elastic Modulus ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Interface Crack ◽  
Functionally Graded ◽  
Physical Parameters ◽  
Mode I ◽  
Modulus Ratio ◽  
Functionally Graded Coating ◽  
Graded Coating

It is assumed that the physical parameters of functionally graded coating material accords with the variation of degree n polynomial, and based on this material model, the behavior of crack fracture on the interface of functionally graded coating is studied. The results show that when the functionally graded coating structure bears a tension load, stress intensity factors of mode I and mode II exist at the same time generally, and the intensity factor of mode I occupies a leading position all along. Besides, when the elastic modulus ratio of the base to the functionally graded coating top is 5 and the elastic modulus of functionally graded coating varies linearly, the stress intensity factor of interface crack is the smallest, and with the increasing of elastic modulus ratio, the optimal non-uniform parameter tends to be larger than 1.

Implementation of Crack Problem of Functionally Graded Materials with ABAQUSTM

2011 ◽  
Vol 284-286 ◽  
pp. 297-300 ◽  
Author(s):  
Hong Liang Zhou
Keyword(s):  
Functionally Graded Materials ◽  
Interface Crack ◽  
Crack Problem ◽  
Functionally Graded ◽  
Closure Technique ◽  
Graded Materials ◽  
Finite Element Software ◽  
User Subroutine ◽  
Implementation Method ◽  
Crack Element

An implementation method of the virtual crack closure technique (VCCT) for fracture problems of non-homogeneous materials such as functionally graded materials (FGMs) with commercial finite element software ABAQUSTMis introduced in this paper. In order to avoid the complex post proceeding to extract fracture parameters, the interface crack element based on the VCCT is developed. The heterogeneity of FGMs is characterized though user subroutine UMAT and the interface crack element is implemented by user subroutine UEL. Several examples are analyzed to demonstrate the accuracy of the present method.

Fracture Analysis of Functionally Graded Thermal Barrier Coating with Interface Crack by Computational Micromechanics Method

2005 ◽  
Vol 492-493 ◽  
pp. 385-390
Author(s):  
Shu Yong Yang ◽  
Li Sheng Liu ◽  
Qing Jie Zhang
Keyword(s):  
Finite Element ◽  
Interface Crack ◽  
Fracture Analysis ◽  
Processing Technique ◽  
Functionally Graded ◽  
Image Processing Technique ◽  
The Finite Element Method ◽  
Barrier Coating ◽  
Equivalent Method ◽  
Computational Micromechanics

The fracture of the functionally graded thermal barrier coating (TBC) under the thermal loads is a key for the engineering application of this kind of materials. In the previous studies, the functionally graded TBC is usually simplified into a laminate by homogenizing the material of each interlayer as an isotropic layer. Nevertheless, this method is a macro equivalent method, which neglected the microstructure characteristics of materials. In this paper, the computational micromechanics method (CMM) is employed to study the fracture problem of the functionally graded TBC with the interface crack. Essentially, CMM is a finite element analytical method based on the real microstructure of materials, which combines the digital image processing technique, the auto mesh generation technique with the finite element method. Firstly, the microstructure photos of the functionally graded TBC are required. Secondly, the digital image processing technique and the auto mesh generation technique are used to construct the finite element model. Finally, the finite element method is utilized for the fracture analysis of the functionally graded TBC under the thermal shock loads. Moreover, the problem is also analyzed using the macro equivalent method and the results from the two methods are compared. The temperature field obtained using CMM is basically consistent with the one obtained from the macro equivalent method and the influences of the interface crack on the temperature fields are limited in a local region. But results of the driving forces for the crack propagation, J-integrals, from the two methods are quite different. Comparing with the CMM results, J-integrals from the macro equivalent method are smaller. It means that the macro equivalent method tends to underestimate the driving force of the interface crack. On the other hand, the prediction of the critical location of the interface crack from the two methods is also different. Since the influence of the microstructure is taken into account by CMM, results of the present work may suggest that CMM is a more useful and accuracy method for the fracture analysis of the functionally graded TBC.

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