Flexural Behaviour of 2D Cellular Lattice Structures Manufactured by Fused Deposition Modelling

Abstract

Cellular lattice structures have applications in crash resistant and protective equipment. This study involves designing rectangular beams of lattice structures with different unit cell configurations, fabricating them on fused deposition modelling (FDM) 3D printing machine and subsequently finding out the structural design for the best flexural performance in engineering applications. All the test specimens were fabricated on Stratasys Dimension 1200 ES FDM machine in acrylonitrile butadiene styrene (ABS) material. Five types of 2D unit cells for building lattice structures were investigated which included honeycomb, diamond, square, circle, and triangle shapes. Three-point bending tests were carried out to study flexural properties like flexural strength and modulus of these cellular lattice structures. After mechanical testing, the obtained data for the five different lattice structures were mutually compared for their flexural behaviour and also with the beams built in solid and sparse shapes. Results of flexural tests indicate that the cellular lattice structures based on triangular and honeycomb shapes exhibit maximum flexural strength. The triangular structure also proved to be the highest in the value of flexural modulus among all the five cellular lattice structures. This study also includes investigating the effects of varying porosity of a particular cellular structure (honeycomb) on its flexural behaviour. Results show that for honeycomb structures, the higher porosity led to higher flexural strength and flexural modulus and shorter build time up to a porosity of 61%.