Design and manufacture of a micro-tensile testing machine for in situ optical observation and DIC analysis: application to 3D-printed and compression-molded ABS

Abstract

In this paper, a novel micro-tensile testing apparatus is designed and built to characterize the micromechanical behavior of materials. Furthermore, a special geometry for micro specimens is introduced that could facilitate problems related to the handling, gripping, and aligning such specimens. The device can be integrated with an optical microscope to observe the microstructural evolution taking place during deformation. Using the developed system, the micromechanical response of additively-printed and compression-molded ABS was determined. 3D-printed specimens demonstrated higher mechanical properties over the compression-molded specimens. Digital image correlation (DIC) technique was also applied to the optical images taken during deformation to measure the strain field in a micron-sized area of interest. DIC results revealed a more intense strain localization for the 3D-printed specimen compared to the monolithic sample. Comparing stress–strain curves and DIC results indicate that the apparatus and technique were quite successful in the in situ characterization of mechanical response.