Flexural Behavior of Bidirectionally Graded Lattice

This study aims to investigate the flexural behavior of newly designed bidirectionally graded lattice beams with body-centered cubic unit cells made of stainless steel 316 L. Uniform and unidirectionally graded lattice beams are also studied for comparison. All the lattice beams are fabricated by electron beam melting and tested under quasi-static bending loads. The experimental results reveal that the flexural stiffness and strength of bidirectional lattice beams are higher than those of both the uniform and unidirectional counterparts. The unidirectional lattice beams display the lowest strength owing to the easier collapse of thinner lattice layers on the impact side with the indenter. Finite element models, developed and validated using the experimental results, are used to evaluate the effects of the density gradient and the loading velocity on the performance of bidirectional lattice beams. The parametric study shows that the flexural stress and the specific energy absorption capacity of bidirectional functionally graded lattice beams increase with increasing loading velocity and can be enhanced by manipulating the layer density gradient.