Example An equation governing interfacial shear stress

2 Example An equation governing interfacial shear stress 

The condition of overall equilibrium for the portion of the film between the 

The extensional elastic strain in the film in the y—direction remains as e-m. following relaxation due to the plane strain constraint. The extensional strain in the x—direction is 

The relationship between the extensional strain along the surface of the substrate es x) and the shear traction q x) corresponding to (4.5) is obtained by superposition over the Flamant solution for a concentrated tangential line load acting on the surface of a half-space (Johnson 1985) as 

Eg is the plane strain modulus of the isotropic elastic substrate and the singular integral is defined in the sense of its Cauchy principal value (Muskhelishvili 1953). 

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