A Numerical-Experimental Study on the Impact Behaviour of Additive Manufactured bcc Lattice Structures

Several industries make an extensive use of sandwich structures in structural design, especially in the aerospace and automotive Engineering fields. Sandwich structures are characterised by two thin layers (skins) with a thick, but light, core in the middle, for increased stiffness to bending. The use of additive manufacturing allows us to adopt very light and geometrically complex cores based on the lattice structures concepts. Lattice structures performances are strongly affected by geometrical factors such as the array configuration, the unit cell shape or topology and the relative density. The research presented in this paper is aimed at adopting hybrid sandwich structures with lattice cores to develop structural engineering solutions characterised by high energy absorption properties and low weight for occupant protection in transportation. Actually, these kind of hybrid shock absorbers have been already demonstrated to be a good compromise between crashworthiness performances and weight efficiency. To improve the shock absorbers designs presented in [1], the additive manufacturing technology has been used to produce three different sandwich panels based on a Body Centred Cubic (BCC) unit cell type, such as a Waved Body Centred Cubic (WBCC) unit cell. The Direct Metal Laser Sintering (DMLS) technology has been adopted by using the EOS M290 3D Printer for metals. The shock absorbers’ configurations have been numerically designed by modifying the core unit cell topology starting from a linear shape to a curved shape with two different orientation.