Damping Analysis and Failure Mechanism of 3D Printed Bio-Based Sandwich with Auxetic Core under Bending Fatigue Loading

Abstract

Meta-sandwich composites with three-dimensional (3D) printed architecture structure are characterized by their high ability to absorb energy. In this paper, static and fatigue 3-point bending tests are implemented on a 3D printed sandwich composites with a re-entrant honeycomb core. The skins, core and whole sandwich are manufactured using the same bio-based material which is polylactic acid with flax fiber reinforcement. Experimental tests are performed in order to evaluate the durability and the ability of this material to dissipate energy. First, static tests are conducted to study the bending behaviour of the sandwich beams, as well as to determine the failure parameters and the characteristic used in fatigue tests. Then, fatigue analyses were carried out to determine the fatigue resistance of these structures. The effects of the core density on the stiffness, hysteresis loop, energy absorption and loss factor, for two loading level, are determined. Moreover, the behaviour of this sandwich composite with re-entrant honeycomb core is compared with that of sandwiches with different core topologies. The results show that sandwich with high core density dissipate more energy, which results higher loss factors. The determined properties offer the most sensitive indicators of sandwich composite damage during its lifetime. This work aims to determine the static and fatigue properties of this material, thus, study its potential applications in industry.