Elastic properties of 3D printed pieces determined with dynamic methods: applications to assembled 3D printed structures

This paper surveys techniques for estimating the modulus of elasticity of 3D printed parts through free vibration tests. The study involves, in the context of common criteria of International Standards, the comparison between different procedures of recording and analyzing the vibratory motion using high precision equipment (proximity sensor connected to professional vibration analyzer) and cheap optical techniques (common high-speed camera and video tracking software). In both procedures, the input motion in the samples is carried out by a sudden low-energy impact. Frequency response functions, natural frequencies, and modes shapes are obtained from the experimental data, to calculate the elasticity modulus of specimens based on appropriate mathematical models and/or standards. The Taguchi method is employed to construct the experiment and the analysis of variance is carried out for evaluating the influence of several parameters of the additive manufacturing process. The elastic properties obtained from the test specimens are then employed in the calculation (by means of finite element procedures) of the dynamic behavior of 3D printed assembled thin walled structures (e.g., U-beam) and contrasted with their corresponding experimental values.