Impact work-rate of a weakly damped beam with elastic two-sided amplitude constraints subject to harmonic excitation is calculated. Impact work-rate is the rate of energy dissipation to the impacting surfaces. The beam is clamped at one end and constrained by unilateral contact sites near the other end. This system was an object of a vibro-impact experiment which was analyzed in our earlier paper (Knudsen and Massih 2000). Detailed nonlinear dynamic behavior of this system is evaluated in our companion paper (Knudsen and Massih 2002b). Computations show that the work-rate for asymmetric orbits is significantly higher than for symmetric orbits at or near the same frequency. For the vibro-impacting beam, under conditions that exhibit a stable attractor, calculation of work-rate allows us to predict the "lifetime" of the contacting beam due to fretting-wear damage by extending the stable branch and using the local gap between contacting surfaces as a control parameter. That is, upon computation of the impact work-rate, the fretting-wear process time is calculated through back-substitution of the work-rate and gap-width in a given wear law.
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