Two-dimensional frictionless contact of a coated half-plane based on couple stress theory

Based on the couple stress theory, the size-dependent frictionless contact problem between a rigid punch and a homogeneous coated half-plane is investigated in this paper. This theory describes the size effect that emerges from the material microstructures by introducing the characteristic material length. With the aid of the Fourier transform method, the size-dependent contact problem of the rigid flat, cylindrical, parabolic and wedge punches is reduced to a Cauchy singular integral equation of the first kind. Subsequently, it is transformed into algebraic ones and solved numerically by using Gauss-Chebyshev integration formulas. Numerical results for the normal and in-plane contact stresses, contact width and indentation depth are given. The effect of the length scale parameters on the contact stress and indentation is predicted by the couple stress elasticity, which shows a strong dependence on the characteristic material length.