Abstract
The current state of art structures incorporate crashworthy crumple zones made of steel, composite or honeycomb structures. The objective of this study is to design, develop and analyze a more lightweight Crashbox using hollow-truss micro-lattice impact absorbing material sandwiched between end plates providing high impact absorbing efficiency due to buckling, repeatable energy absorption and more duration of compression. Impact loading on the Crashbox is studied using various researches done on crash scenarios and crash tests in the industry. For the given impact load, hollow tube (truss) micro-lattice structure is designed by calculating and varying the lattice parameters and configurations i.e. Hollow truss diameters, edge length, relative density etc. BCC structures micro-lattice block is premeditated for its uniaxial compressive mechanical properties using conventional beam theory for determining the lattice parameters (mainly relative density). Then for impact loading; threshold stress, allowable transmitted stress, impact energy absorption efficiency is studied. Up till densification of micro-lattice takes place and strain reaches stagnation point, impact energy absorbed can be used for impact attenuation. FEM analysis using 1-D and 3-D elements are used to obtain numerical results which are compared with theoretical results (beam theory). In the paper stress-strain curves are obtained at various checkpoints to analyze the energy absorption feature of the micro-lattice structures based on mechanical properties and experimental results. It is concluded that varying the topology, relative density and lattice parameters of micro-lattice block, creates a large difference in impact attenuation offered by crashbox. Close to accurate FEA modeling of the lattice structure is laid down and compared to the theoretical approach which gives correct design parameters to be incorporated for optimum strength to weight ratio.
Keywords: Impact loading, Micro-lattice structure,Crashbox, lightweight, Crashworthiness