Determination of experimental uncertainties in tensile properties of additively manufactured polymers using the GUM method

Abstract

Uncertainty analysis or error analysis refers to the process of evaluating uncertainty associated with a measurement result. This paper discusses the uncertainty associated with tensile test results coupons manufactured using additive manufacturing (also known as 3D printer). The tensile specimens are made from a commercial acrylonitrile-butadiene-styrene (ABS) polymer (P430) polymer materials and the uncertainty estimation was obtained by using the Guide of Uncertainty Measurement approach. Although neither tensile testing nor error propagation are novel, there is little research documenting the error propagation of tensile tests using the Guide of uncertainty measurement approach. The tensile coupons were built on flat at different build orientations of 0°, 22.5°, 45°, 67.5°, and 90° and were then subjected to mechanical testing. The uncertainty propagation associated with the measuring instruments was calculated. The uncertainty in cross-section area, ultimate tensile strength, yield strength and the Young’s modulus was then estimated. It was found that the cross-sectional area has a higher uncertainty due to inaccuracies measurement for the original width and thickness. This observation was recorded for the additively manufactured part built at 0° build orientation. It can be concluded that the variation and inaccuracies has contributed to a greater uncertainty in the ultimate tensile strength, yield strength and the Young’s modulus results.