On the design of interferenced and clamped joints under general state of stress

Problems arising in the case of assuming general stress state in the interferenced joint are considered in this paper. FEM program using sensitivity matrix method written by the authors has been used for the analysis of non-linear contact problems (cf Osiński and Sztwiernia (1994)). It includes non-linear characteristics of the stress-strain dependence that allows calculation of pre-plasticity of rough surfaces and plasticity. Full stress cycle has been applied to the joint; i.e., loading, unloading, loading. The results made it possible to plot the hysteresis loop. In particular the analysed issues are the effect of boundary conditions (bush attachment) and joint dimensions. Big difference has been highlighted between authors' results and the ones obtained for simplified models for short joints of big diameter. The hysteresis loop is shifted and its area is much bigger. The influence of contact pressure increase in the edge area was also considered. An analytical method was also developed. The influence of pressure increase has small effect on energy dissipation. It has been stated that in the analysis of contact problems with friction (structural damping) the use of general state of stress is recommended. The uniaxial torsion assumption is a great simplification. The FEM program using the sensitivity matrix method turned out to be a very efficient tool in the analysis of contact problems.