Hybrid spatial uncertainty analysis for the estimation of imprecise failure probabilities in Laser Sintered PA-12 parts

Abstract

This paper presents the application of non-deterministic modelling techniques for the quantification of imprecise failure probabilities in PA-12 parts produced via Laser Sintering (LS). Specifically, a modelling approach consisting of a combination of interval and random fields is applied, and the effect hereof on the resulting polymorphic uncertainty in the mechanical performance of the LS parts is studied. A link with the underlying process physics is given, relating the spatial porosity distributions that are inherently present in LS PA12 parts to a spatial distribution in the apparent Young’s modulus. Furthermore, uncertainty on the final dimensions of other parts that are constructed in the same build envelope as the designed part is linked to uncertainty in the cross-sectional area of the designed part.The effect of these sources of uncertainty is studied in three case studies, illustrating the need for a well-thought production process planning given the influence on the resulting mechanical performance of the designed structure. Especially the effect of epistemic uncertainty on the design process is shown to be significant.