Numerical analysis on the clamping reliability of fixture-workpiece facility considering partial slip

Fixture is a mechanical component to clamp a workpiece and to move it to a specific position. This paper analyses partial slip at the fixture-workpiece interface and addresses the effects of design parameters and working conditions of a fixture-workpiece facility on clamping reliability. A stick ratio, defined as the ratio of the stick area to the entire nominal contact area, is introduced in this study to characterize the clamping reliability. If the value of stick ratio equals to one, the clamping is most reliable, but when it drops to zero, a gross sliding will occur, which means clamping failure. This paper investigates the partial slip phenomenon by solving threedimensional contacts between elastically dissimilar materials, using the conjugate gradient method (CGM) and discrete convolution-fast Fourier transform (DC-FFT) techniques, but focuses on its industrial applications. Results have demonstrated how the inferential factors, such as material property, normal and tangential loads, operational parameters, and geometric features of the fixture, would affect the clamping reliability, which can be used for guiding the design of the fixture, for example, the choice of material, friction coefficient, fixture's opening angle, acceleration in manipulation, and so on.