Measurements of pressure and area dependent tangential contact stiffness between rough surfaces using digital image correlation

The present paper describes an experimental technique to accurately measure the tangential contact stiffness between two rough contacting surfaces manufactured from the titanium alloy Ti–6Al–4V. The digital image correlation method is employed to measure the local displacement field. The effect of normal contact pressure, nominal contact area and fretting wear on tangential contact stiffness is investigated. The experiments indicate that the tangential contact stiffness is approximately proportional to the nominal contact area and the normal pressure raised to the power of 0.64. Multiple experiments with the same parameters show good repeatability given the number of variables involved.

► Digital image correlation for accurate measurement of tangential contact stiffness.
► We use flat pads with rounded corners clamped against the flat surface of a specimen.
► Effect of contact pressure, contact area and wear on stiffness is investigated.
► Using the same experimental parameters, the repeatability of results is investigated.