Dynamic Characterization of a Bio-Based Sandwich with Auxetic Core: Experimental and Numerical Study

The flexural vibration and damping performances of a bio-based sandwich structure with auxetic core are investigated in this paper. The material studied is made up of an auxetic core and two skins. Each of the skins and core are made up of a polylactic acid reinforced with flax fibers. The whole sandwich structure was manufactured using a three-dimensional (3D) printing technique. Experimental analysis was used to evaluate the damping properties of this material. The skins, the core and the whole sandwich structure were tested experimentally in a clamp-free configuration. In addition, a finite element model was developed to evaluate the loss factors and natural frequencies regarding different cases. The influence of the relative core densities and thicknesses on the dynamic stiffness and loss factors were measured and discussed. The results obtained from the experiment and the numerical analysis were in a close agreement.