Interference Assemblies

This paper contains the development of a method for determining the contact pressure distribution along the mating surfaces of two members assembled together with an initial interference fit. This method utilizes superposition, Fourier-series expansion techniques, and the finite-element method to determine the desired contact pressure distribution. The general approach to the solution of this problem entails assuming a Fourier-series representation of the contact pressure distribution expressed in terms of unknown Fourier coefficients. Superposition and finite-element methods are used to determine the displacement vector at common nodal points along the mating surfaces of the two members. The correct distribution of contact pressure results when these nodal displacements satisfy the initial interference between the two members. Enforcing this displacement requirement yields a system of equations from which the unknown Fourier pressure coefficients can be determined. Once the correct contact pressure distribution is known, the resulting stress distributions and deformations in the inner and outer members can be calculated. This method is illustrated and numerical results are obtained for the case where an outer member having an irregular-shaped boundary is shrunk onto a solid circular shaft representing the inner member.