Approximation of contact stress for a compressed and laterally one side restrained O-ring

This paper revisits the classical O-ring problem by using an experimental, finite element analysis and conventional theories. Especially, the elastic moduli, deformation shape, friction coefficient and extrusion behaviour were investigated in detail during the experiments. A computed tomography was used to detect the deformed shape of the O-ring. The used finite element method results were validated by comparing them with the experimental results. For an application to the present study, an actual case of a compressed and laterally one side restrained condition was analyzed experimentally and numerically. As a result of the finite element analysis, the friction coefficient affects the contact stress profile and magnitude considerably. Lindley's formulae for a contact (compressive) force underestimated the measured force but it showed similar results to the finite element analysis results. Applicability of the Hertz theory to the contact stress field was discussed by comparing it with the finite element analysis results in the case of a compressed and laterally one side restrained condition. Consequently, it was found that the normalized results with respect to the peak stress and contact width followed the typical Hertzian profile. So an implementation of the appropriate factors to the Hertz equation can yield an approximate solution of the contact stresses.