A novel integrated modeling strategy for predicting damage mechanisms and energy dissipation of composite stiffened structures under low-velocity impact and compression

Aiming at the limitations of mechanical behavior analysis method of composite structures in multi-model prediction, a novel integrated finite element model containing low-velocity impact (LVI) and compression after impact (CAI) is established, which can effectively simulate the failure mechanism and energy dissipation characteristics of composite stiffened structures under complex working conditions. Firstly, strain-based 3D-Hashin criterion, continuum damage mechanics model and cohesive zone model are used to predict the intra- and inter-laminar damage of composite stiffened structures and are implemented in Abaqus/explicit solver in combined with VUMAT subroutine. Moreover, the reliability of the proposed modeling strategy is verified via various test methods such as the LVI test platform, universal testing machine and digital image correlation technique. Finally, the effects of different impact energies on the mechanical response, failure mechanism, energy dissipation and residual bearing performance of composite stiffened structures with flange edge impact are further revealed. The results show that the deltoid and 0 degrees degrees layups dissipate more energy and accommodate the larger load. Matrix tensile damage and interface debonding are considered to be the main damage modes in composite stiffened structures. The novel integrated modeling strategy not only improves the inefficient transfer of damage information between multiple models but also avoids the shortcomings of the large bias in the prediction results of the equivalent analysis method. This research provides a reference for the application of composite stiffened structures for aerospace in multiple working conditions.