Application of the Dynamic Indentation Method for Evaluation of the Hardness and Elastic Modulus of the Material of Products Obtained by Extrusion Method of Additive Production from Carbon-Filled Composite Materials

Abstract

The possibility of using the dynamic indentation method (DIM) for evaluating the elastic and strength characteristics of products made of carbon-filled SAN plastic (acrylonitrile styrene) obtained by additive synthesis using the extrusion technology of 3D printing -FDM technology (Fused deposition modeling) -in different directions is shown. An influence of surface roughness of the products tested in the range of 2.0 to 3.6 Ra on the results of measuring the dynamic hardness and dynamic elastic modulus was investigated. It is shown that the initial roughness of the specimen surface of 3.6 Ra leads to an increase in the measurement error of the physical and mechanical characteristics using DIM up to 16% and increases the coefficient of variation. The loading parameters (spherical indenter of 5-mm diameter, impact energy of 42 mJ) for the materials investigated were determined, which allow one to obtain reliable numerical data of the physical and mechanical characteristics (in the range of variation of the strength 16-33 MPa and elastic modulus 1.4-3.0 GPa) of the products inspected. The results obtained can be used for the creation of portable measuring devices that allows one to provide in-situ testing of products manufactured by 3D printing (FDM technology), without the use for standard destructive tests on the witness specimens.