Abstract
The low velocity impact response of sandwich structures with graded foams cores have been investigated both experimentally and numerically. Sandwich structures, based on graded foams, were fabricated by bonding carbon fibre skins and three foam sheets with differing densities. Twelve combinations of graded foam core were investigated based on a range of crosslinked PVC, liner PVC and PEI foams. The structures were loaded by a drop-weight impact carriage with a hemispherical projectile and the load-displacement traces were recorded. The dynamic response of the panels was characterised by determining the energy required to perforate the target. The impact responses of the panels were also predicted using the finite element technique. The failure modes in the graded sandwich structures were examined and it was observed that many panels fractured in a through-thickness shearing mode, leaving a cylindrical hole in the graded foam cores. A mixed tensile/shear mode was also observed resulting in cone cracking on the exit surface in a limited number of panels. The most impressive structures were those associated with placing a high density foam core at the top surface, a low density foam in the centre and a ductile foam at the rear surface. The FE model produces the predictions of both the load-displacement responses and the perforation energies of the structures accurately. The predictions have also been used to demonstrate that graded foam core can out-perform their monolithic counterparts in terms of their impact resistance.
Original language | British English |
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State | Published - 2015 |
Event | 20th International Conference on Composite Materials, ICCM 2015 - Copenhagen, Denmark Duration: 19 Jul 2015 → 24 Jul 2015 |
Conference
Conference | 20th International Conference on Composite Materials, ICCM 2015 |
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Country/Territory | Denmark |
City | Copenhagen |
Period | 19/07/15 → 24/07/15 |
Keywords
- Finite element
- Graded foam Cores
- Impact
- Sandwich structures