Loose-part mass and energy estimation

Expressions for loose-part momentum and impact force were derived as functi ons of plate bending wave surface acceleration and primary frequency conten t. These relationships were used to constrain the loose-part diagnostic pro blem so that loose part mass and impact energy can be determined for credib le values of contact radius. Uncertainties associated with unknown contact radius were evaluated by simulation, and experimental data were analyzed fo r multiple energy impacts by metal spheres having mass between 0.15 and 32 Ibs. Significant biases were found to exist when using apparent impact cont act time information based on the two-dimensional Lamb wave model. Using th e mass estimation method and bias estimates, an iterative technique was dev eloped that converges to close to the theoretical contact time. The results provide methods for loose-part mass and energy estimation and for evaluati ng the effects of uncertainty in loose part location and signal transmissio n attenuation. (C) 1998 Elsevier Science Ltd. All rights reserved.