Evaluation of a Model for the Evolution of Wear in a Scotch-Yoke Mechanism

A nearly ideal two-dimensional scotch yoke mechanism was constructed to test a model of wear depth as a function cycle number. Model variables include the reciprocating mass, a two dimensional wear-rate, crank radius, and angular velocity. The model originally developed by T. A. Blanchet (1997), was nondimensionalized and simplified under conditions of large numbers of cycles, to predict the importance of including coupling based solely on a ratio of maximum allowable wear depth to the crank radius. Experiments show a linear progression of wear over two distinct regions, suggesting a sudden transition in wear modes just after 1.5 million cycles. The need for cycle or time dependent wear rates in analysis, which is a potentially far more significant source of error, is clearly illustrated by the experiment and discussed.