Transient analysis of stationary interface cracks in orthotropic bi-materials using oscillatory crack tip enrichments

2016 ◽  
Vol 142 ◽  
pp. 200-214 ◽  
Author(s):  
Arman Afshar ◽  
Saeed Hatefi Ardakani ◽  
Soheil Mohammadi
Keyword(s):  
Transient Analysis ◽  
Crack Tip ◽  
Interface Cracks ◽  
Stationary Interface

Mixed Mode Loading of an Interface Crack Subjected to Creep Conditions

2003 ◽  
Author(s):  
Ali P. Gordon ◽  
David L. McDowell
Keyword(s):  
Transition Layer ◽  
Mixed Mode ◽  
Elevated Temperatures ◽  
Numerical Solutions ◽  
Crack Tip ◽  
Functionally Graded ◽  
Pure Mode ◽  
Mixed Mode Loading ◽  
Creep Ductility ◽  
Interface Cracks

Interface cracks are seldom subjected to pure Mode I or pure Mode II conditions. Stationary interface cracks between two distinct, bonded elastic-creep materials subjected to remotely applied mixed mode loading are simulated. The finite element method (FEM) is used to examine crack tip fields and candidate driving force parameters for crack growth. Plane strain conditions are assumed. In most cases a functionally graded transition layer is included between the two materials. Examples of such systems include weld metal (WM) and base metal (BM) interfaces in welded or repaired boiler components subjected to elevated temperatures. Numerical solutions based on the asymptotic fields of the homogeneous and heterogeneous Arcan-type specimens are presented. Creep ductility-based damage models are used to predict the initial crack propagation trajectory. The incorporation of functionally graded transition layer regions affects the evolution of time-dependent stress components in the vicinity of the crack tip. The magnitude and direction of crack tip propagation can then be optimized with respect to interface properties.

scholarly journals On stationary and moving interface cracks with frictionless contact in anisotropic bimaterials

1993 ◽  
Vol 443 (1919) ◽  
pp. 563-572
Keyword(s):  
Crack Problem ◽  
Stress Singularity ◽  
Crack Tip ◽  
Substantial Part ◽  
Open Crack ◽  
Interface Cracks ◽  
Complete Representation ◽  
Crack Tip Fields ◽  
Out Of Plane ◽  
Anisotropic Bimaterials

The asymptotic structure of near-tip fields around stationary and steadily growing interface cracks, with frictionless crack surface contact, and in anisotropic bimaterials, is analysed with the method of analytic continuation, and a complete representation of the asymptotic fields is obtained in terms of arbitrary entire functions. It is shown that when the symmetry, if any, and orientation of the anisotropic bimaterial is such that the in-plane and out-of-plane deformations can be separated from each other, the in-plane crack-tip fields will have a non-oscillatory, inverse-squared-root type stress singularity, with angular variations clearly resembling those for a classical mode II problem when the bimaterial is orthotropic. However, when the two types of deformations are not separable, it is found that an oscillatory singularity different than that of the counterpart open-crack problem may exist at the crack tip for the now coupled in-plane and out-of-plane deformation. In general, a substantial part of the non-singular higher-order terms of the crack-tip fields will have forms that are identical to those for the counterpart open-crack problem, which give rise to fully continuous displacement components and zero tractions along the crack surfaces as well as the material interface.

The r−1/2 (ln r) Singularities at Interface Cracks in Monoclinic and Isotropic Bimaterials due to Heat Flow

1993 ◽  
Vol 60 (2) ◽  
pp. 432-437 ◽  
Author(s):  
G. Yan ◽  
T. C. T. Ting
Keyword(s):  
Heat Flow ◽  
Interface Crack ◽  
Simple Form ◽  
Crack Tip ◽  
Higher Order ◽  
Stress Singularities ◽  
Interface Cracks ◽  
Existence Conditions

It is known that the stress singularities at an interface crack tip of bimaterials with the effects of heat flow may have the form r−1/2 (ln r). The existence conditions of the higher order singularitiy r−1/2 (ln r) are studied for monoclinic bimaterials whose plane of symmetry is at x3 = 0. It is shown that the higher order singularity does not exist if the bimaterial is mismatched. If the bimaterial is non-mismatched, the higher order singularity does not exist when a certain condition is satisfied. This condition is given explicitly for monoclinic bimaterials with the plane of symmetry of x3 = 0 and in a simple form for isotropic bimaterials.

Time Dependent Stress Fields Ahead of the Interface Cracks in Creep Regime

1996 ◽  
Vol 434 ◽  
Author(s):  
S. B. Biner
Keyword(s):  
Applied Load ◽  
Layered Materials ◽  
Time Dependent ◽  
Stress Fields ◽  
Mode I ◽  
Strain Condition ◽  
Transitional Layer ◽  
Interface Cracks ◽  
Stationary Interface ◽  
Creep Regime

AbstractIn this study the behavior of stationary interface cracks in layered materials at creep regime in plane-strain condition and pure opening dominated mode-I load state was studied numerically. The results indicate that the introduction of a transitional layer to the interface of the elastic-creeping bimaterials significantly elevates the stress values ahead of the interface cracks under identically applied load levels at creep regime.

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