Multiscale Designer, developed by Altair, has been studied for its suitability for fatigue life prediction of advanced composite aircraft structures made of polymer matrix composites. The extensive experimental data provided by the Air Force Research Laboratory have been utilized to characterize the linear, non-linear, monotonic, and cyclic loading properties of micro-constituents comprising the polymer matrix composite system. The characterized properties have been then utilized to predict fatigue life and residual strength and stiffness of the aerospace grade polymer matrix composites.