Response of sandwich structures with pyramidal truss cores under the compression and impact loading

In this paper, the pyramidal truss core sandwich structures consisting of carbon fiber reinforced polymer (CFRP) facesheets and aluminum alloy cores were manufactured based on the slot-fitting method. This hybrid concept is to maximize the specific bending stiffness/strength as well as obtain excellent energy absorption ability. Quasi-static compression tests were conducted to get the stress–strain curves and to evaluate the energy absorption mechanism. Low velocity impact tests were carried out to investigate the damage resistance of such structures. The compressive measurements show that the low density aluminum alloy pyramidal truss cores have superior energy absorption ability compared with other lightweight lattice cores. In the impact tests, the failure of matrix cracking, fiber breakage, delamination of CFRP facesheets and buckling of truss members occurred and the extent of damage was significantly affected by the impact site. In addition to experimental testing, finite element models for compression and impact simulations have been developed using ABAQUS software. The numerical results were validated compared with the experimental tests.