Finite element analysis of low-velocity impact on composite sandwich plates

The response of composite sandwich plates to low-velocity impact is predict ed by a displacement-based, plate bending, finite element algorithm. Fifth order Hermitian interpolation allows three-dimensional equilibrium integrat ion for transverse stress calculations to be carried out symbolically on th e interpolation functions so that transverse stresses within the elements a re expressed directly in terms of nodal quantities. Nomex honeycomb sandwic h core is modeled using an elastic-plastic foundation and contact loading i s simulated by Hertzian pressure distribution for which the contact radius is determined iteratively. Damage prediction by failure criteria and damage progression via stiffness reduction are employed. Comparison to experiment al low-velocity impact and static indentation data shows the ability to mod el some of the important features of static indentation of composite sandwi ch structures. In particular, the slope of the load displacement curve (sti ffness), including contact, before damage is well represented. Core failure load is predicted by the analysis within 10% of the experimental value. Pu blished by Elsevier Science Ltd.