A method is presented to identify indirectly loads moving on an orthotropic plate. The loads are in a group of two forces or four forces. The dynamic behavior of the plate under the action of these moving loads is analyzed. A method to identify these moving forces from the dynamic responses of the plate is developed basing on the modal superposition principle, and Tikhonov regularization procedure is applied to provide bounds to the solution in the time domain. Prior knowledge on the modal properties of the plate and the velocity of loads is required. The errors in the identified individual loads are discussed. The effect of different combinations of measuring locations on the identification is studied. Numerical results show that acceleration responses would give better and acceptable results than strain measurements.

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