Structural Response Prediction of Thin-Walled Additively Manufactured Parts Considering Orthotropy, Thickness Dependency and Scatter

Abstract

Besides the design freedom offered by additive manufacturing, another asset lies within its potential to accelerate product development processes by rapid fabrication of functional prototypes. The premise to fully exploit this benefit for lightweight design is the accurate structural response prediction prior to part production. However, the peculiar material behavior, characterized by anisotropy, thickness dependency and scatter, still constitutes a major challenge. Hence, a modeling approach for finite element analysis that accounts for this inhomogeneous behavior is developed by example of laser-sintered short-fiber-reinforced polyamide 12. Orthotropic and thickness-dependent Young’s moduli and Poisson’s ratios were determined via quasi-static tensile tests. Thereof, material models were generated and implemented in a property mapping routine for finite element models. Additionally, a framework for stochastic finite element analysis was set up for the consideration of scatter in material properties. For validation, thin-walled parts on sub-component level were fabricated and tested in quasi-static three-point bending experiments. Elastic parameters showed considerable anisotropy, thickness dependency and scatter. A comparison of the predicted forces with experimentally evaluated reaction forces disclosed substantially improved accuracy when utilizing the novel inhomogeneous approach instead of conventional homogeneous approaches. Furthermore, the variability observed in the structural response of loaded parts could be reproduced by the stochastic simulations.

The Mechanical Properties of Direct Metal Laser Sintered Thin-Walled Maraging Steel (MS1) Elements

“…Much of the research in this area was devoted to the design, fabrication, and properties of thin-walled elements, as recently these have been in higher demand [ 6 , 17 , 18 , 19 , 20 , 21 ]. Some interesting findings were discussed in [ 6 ]; they concerned the relationship between the thickness and tensile strength of Ti-6Al-4Vl alloy specimens fabricated by EBM.…”

Flexural Properties of Thin-Walled Specimens with Square Hollow Sections 3D Printed from ABS Reinforced with Aramid Fibers

“…In the case of testing thin-walled models, exemplary tests are presented in articles [23][24][25]. Also in these works, the analysis of the problems of generating G-codes in terms of strength was not presented.…”

“…Also in these works, the analysis of the problems of generating G-codes in terms of strength was not presented. Papers [24,25] present interesting examples of filling models with a cellular structure but without a deeper analysis of the technological process taking into account the method of forming the filling (thin walls).…”

Experimental Quantification of the Variability of Mechanical Properties in 3D Printed Continuous Fiber Composites

“…This is quickly becoming a critical design and manufacturing issue as technology steadily progresses towards true 3D printing, where even more uncertainties occur. Additionally, numerical simulation plays an increasingly important role in the development process of lightweight parts, such as motorbike components [47]. Consequently, fewer prototypes are needed to perform the required mechanical testing, which shortens development times.…”