The significance of shear and normal force components on tube wear due to fretting and periodic impacting

Abstract To estimate the working life or the acceptable vibration limit for heat exchangers and similar types of engineering components that are subjected to random motions, special wear prediction techniques are needed. Tube fretting wear was found to relate to the dynamic interaction, or impact force, between the tube and its support. The instantaneous reaction forces at the support were resolved into shear and normal components. Force functions derived from the shear force components were found to correlate well with the wear rates. The results also show that tube fretting wear is mainly a function of the impact force and the angle of impact. Without the sliding (or shear) component the wear rate remains low.