Formulation and Application of a Stochastic Fatigue Damage Accumulation Model for the Response of Buckled Composite Panels

摘要

This report documents the results of an SBIR Phase I feasibility study on the prediction of the fatigue of composite panels subjected to an extreme environment, i.e., both high temperatures (and temperatures gradients) and a transverse acoustic loading. Of particular interest in this study are situations in which the plate is buckled by the thermal effects and experiences frequent snap-throughs, i.e., excursions from one buckled state to the other. First, a large displacements small strains structural dynamic formulation is developed that accounts for the given temperature effects and relies on a higher-order shear modeling. Then, a one-mode approximate representation of the panel dynamics is derived that is shown to reduce substantially the complexity of the problem while retaining the essential physics. Next, two equivalent linearization strategies are formulated for the derivation of approximate models of the probability density function of the panel response. Finally, the damage prediction is accomplished by relying on three separate damage scenarios that permit a reliable estimation of the damage in a wide range of conditions, extending specifically from the limiting case of infrequent snap-throughs to the situations in which this behavior dominates the panel response.