Design optimization for manufacturability of axisymmetric continuum structures using metamorphic development

Abstract

In this study, optimal shapes/profiles of axisymmetric continuum structures optimized for performance and manufacturability are sought, using a topology/shape optimization method called metamorphic development (MD). The optimization seeks to find an optimum cross-sectional profile and minimum weight design, subjected to von-Mises stress constraints under coupled thermal and pressure loadings. Both quadrilateral and triangular finite elements (FE) were used to 'metamorphically' develop the structure. Two different design optimization approaches were taken, by defining a set of finite 'restricted' and 'unrestricted' design domains. Manufacturability of the optimized structures was considered. Prior to manufacturing, a post-optimization process was performed. A comparison was then performed for both sets of optimized solutions to demonstrate whether the 'restricted' design domain solution gave greater or lesser performance characteristics compared to the 'unrestricted' design domain solution which could only be manufactured by additive manufacturing technologies (AMT). The results of the optimization demonstrated the success of the MD method in generating practical design solutions which meet both performance requirements and manufacturing considerations.

Design optimization of consolidated granular-solid polymer prismatic beam using metamorphic development

“…From a physical viewpoint, neither vertices of infinite curvature nor infinite stresses should exist. Sharp concave vertices can be eliminated though postoptimization by spline curve fitting and remeshing the newly created layout (Ngim et al, 2007). In this study, the optimized solution was retained, in order to facilitate the generation of an analysis model, and thereby investigate experimentally the performance of design solutions obtained directly by MD.…”

“…The benefits of optimized structures are seldom realized, often due to geometric complexities, which restrict the necessary tooling access required by convectional subtractive-based manufacturing. Chang and Tang (2001) and Ngim et al (2007) demonstrated the design optimization for manufacturability, by collective technologies known as rapid manufacturing (RM), which offered the ability to produce optimized structures of virtually any geometric complexity (Wohlers, 2004). This current study was motivated by the applications of RM-based technologies, such as contour crafting (Khoshnevis, 2004) and freeform construction (Pegna, 1997;Buswell et al, 2007) which formed the basis of enabling technologies to address additive manufacturing solutions envisaged for future construction applications.…”

A preliminary design method for axisymmetric turbomachinery disks based on topology optimization

“…23 In these literatures about the optimization of disks, the optimal results tended to contain enclosed holes 19 which may challenge the manufacturing processes. 20 Besides, as observed in Rindi et al., 23 the optimal results tended to have indistinct solid-void interface.…”

“…17 The cooling channels in turbine blades were optimized in Ghosh et al. 18 Topology optimizations of turbomachinery disks were conducted in Shen et al., 19 Ngim et al., 20 Boccini et al., 21 , 22 and Rindi et al. 23 In these literatures about the optimization of disks, the optimal results tended to contain enclosed holes 19 which may challenge the manufacturing processes.…”

Filament path optimization of Fused Filament Fabricated parts incorporating the effect of pre-fusion densities

“…The present work aims at contributing to the filament path optimization of load-bearing FFF structures for maximizing their stiffness. A number of studies in the literature successfully employed optimization approaches to design AM parts with optimal topologies and mesostructures (Ngim et al (2007); Gaynor (2015); Zegard and Paulino (2016); Liu et al (2018)). Surprisingly, only a limited attention has been given to optimize the in-plane material placement in AM parts that is clearly advantageous for extrusionbased technologies (Tam and Mueller (2017), Zhang et al (2017)).…”