A critical comparison of two methods for solving elastic contact problems with friction

Formulation and Implementation of Conditions for Frictional Contact

Abstract: Finite element implementations of the classical (stick‐slip) and a regularized (elastic‐slip) friction laws are compared for a class of non‐linear slip criteria. The fully implicit method is used for integrating the friction law. A novel implementation of the stick‐slip law, that involved transformation to a non‐orthogonal coordinate system at each contact point, is assessed. A numerical comparison is carried out for a simple problem, that has previously been analysed in the literature. The convergence of the elastic‐slip law for increasing stiffness is evaluated in addition to convergence behaviour of the adopted Newton iterations for a given law.

A finite element solution for the two‐dimensional elastic contact problems with friction

Abstract: A numerical procedure developed for solving the two-dimensional elastic contact problems with friction is presented. This is a generalization of a procedure developed by Francavilla and Zienkiewicz to include frictional effects under proportionate loading. The method uses the flexibility matrix obtained by inversion of condensed stiffness matrix formed by eliminating all the nodes except those where contact is likely to take place and those with external forces. Compatibility of displacements for both normal and tangential directions is applied to those nodes which do not slip. However, for the nodes which slip, compatibility of displacements is applied for normal direction only and slip condition is applied in the tangential direction. The technique has been applied to several problems and very good results have been obtained. The number of iterations needed are very small.

Finite Element Analysis of Elastic Contact Problems

Abstract: This paper discusses a method for evaluation of contact stresses between two or more elastic bodies with frictional forces on the contact surfaces, by means of a finite element method. The matrix equation is solved by some nodal points being prepared on the contact surfaces. These nodal points are classified into "adhere to" or "slide over" one another categories, depending upon whether frictional forces are greater than the shearing forces or not, and contact conditions are applied for each case. For example, numerical results for two rectangular plates and two cylindrical columns having different sizes and Young's moduli which are compressed into one another are obtained. Contact pressure along the contact surface of rectangular plates without friction is in good agreement with the exact solution for semi-infinite plate, except near the end of the contact surface. Also the influences of friction on the contact stresses are discussed.