Fretting wear volume calculation on cylindrical surface: Inaccuracy due to misalignment of measured object with respect to 3D profiler

Wear volume can be computed from the topography of the wear scar and surrounding region. On single curvature surface whose axis of revolution is aligned to a measuring path of the profiler, the profile over the intact zone fits into a straight line. The line is used for the calculation of the cross sectional area of wear scar which is integrated to obtain the wear volume. If misaligned, however, the line found by the linear regression is an approximation for the intact surface and the resulting wear volume is erroneous to some degree. Parametric studies show the dependence of the error on the misalignment angle, the surface curvature, the wear depth, and the relative widths of the intact and the scar zones. An alternative to avoid the misalignment problem is to use surface fitting which determines the malposition parameters in the equation of the surface. Fretting wear volume of a tube specimen is calculated by the surface fitting and compared with the linear regression results.