Determination of thermal stress intensity factors for an interface crack under vertical uniform heat flow

1991 ◽  
Vol 40 (6) ◽  
pp. 1067-1074 ◽  
Author(s):  
Kang Yong Lee ◽  
Chang Won Shul
Keyword(s):  
Thermal Stress ◽  
Stress Intensity ◽  
Heat Flow ◽  
Interface Crack ◽  
Stress Intensity Factors ◽  
Intensity Factors ◽  
Uniform Heat

Interface Crack Between Two Dissimilar Half Spaces Subjected to a Uniform Heat Flow at Infinity—Open Crack

1990 ◽  
Vol 57 (2) ◽  
pp. 359-364 ◽  
Author(s):  
An-Yu Kuo
Keyword(s):  
Thermal Stress ◽  
Stress Intensity ◽  
Temperature Distribution ◽  
Heat Flow ◽  
Interface Crack ◽  
Stress Intensity Factors ◽  
Crack Surface ◽  
Open Crack ◽  
Intensity Factors ◽  
Uniform Heat

The thermal stress problem of an “open” crack situated at the interface of two bonded, dissimilar, semi-infinite solids subjected to a uniform heat flow is studied. Heat transmission between adjacent crack surfaces is assumed to be proportional to the temperature difference between the crack surfaces with a proportional constant h, which is defined as the contact coefficient or interface conductance. Temperature distribution of the problem is obtained by superimposing the temperature field for a perfectly bonded composite solid and the temperature fields for a series of distributed thermal dipoles at the crack location. The distribution function of the dipoles is obtained by solving a singular Fredholm integral equation. Stresses are then expressed in terms of a thermoelastic potential, corresponding to the temperature distribution, and two Muskhelishvili stress functions. Stress intensity factors are calculated by solving a Hilbert arc problem, which results from the crack surface boundary conditions and the continuity conditions at the bonded interface. Thermal stress intensity factors are found to depend upon an additional independent parameter, the Biot number λ = (ah/k), on the crack surface, where a is half crack length and k is thermal conductivity. Dipole distribution and stress intensity factors for two example composite solids, Cu/Al and Ti/Al2O3, are calculated and plotted as functions of λ. Magnitude of the required mechanical loads to keep the interface crack open is also estimated.

A Method to Extract Interface Stress Intensity Factors Using Interlayers

2005 ◽  
Author(s):  
Sridhar Santhanam
Keyword(s):  
Stress Intensity ◽  
Interface Crack ◽  
Stress Intensity Factors ◽  
Crack Problem ◽  
Interface Stress ◽  
Mode I ◽  
Universal Relation ◽  
Intensity Factors ◽  
Infinite Blocks

A method is presented here to extract stress intensity factors for interface cracks in plane bimaterial fracture problems. The method relies on considering a companion problem wherein a very thin elastic interlayer is artificially inserted between the two material regions of the original bimaterial problem. The crack in the companion problem is located in the middle of the interlayer with its tip located within the homogeneous interlayer material. When the thickness of the interlayer is small compared with the other length scales of the problem, a universal relation can be established between the actual interface stress intensity factors at the crack tip for the original problem and the mode I and II stress intensity factors associated with the companion problem. The universal relation is determined by formulating and solving a boundary value problem. This universal relation now allows the determination of the stress intensity factors for a generic plane interface crack problem as follows. For a given interface crack problem, the companion problem is formulated and solved using the finite element method. Mode I and II stress intensity factors are obtained using the modified virtual crack closure method. The universal relation is next used to obtain the corresponding interface stress intensity factors for the original interface crack problem. An example problem involving a finite interface crack between two semi-infinite blocks is considered for which analytical solutions exist. It is shown that the method described above provides very acceptable results.

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