scholarly journals Topology Optimization for Manufacturing with Accessible Support Structures

2022 ◽  
Vol 142 ◽  
pp. 103117
Author(s):  
Amir M. Mirzendehdel ◽  
Morad Behandish ◽  
Saigopal Nelaturi
Keyword(s):  
Topology Optimization ◽  
Support Structures

scholarly journals On preventing the dripping effect of overhang constraints in topology optimization for additive manufacturing

2021 ◽  
Author(s):  
Alain Garaigordobil ◽  
Rubén Ansola ◽  
Igor Fernandez de Bustos
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Prevention Strategy ◽  
Alternative Strategy ◽  
Manufacturing Processes ◽  
Support Structures ◽  
Local Minimizers ◽  
Constraint Function ◽  
Temporary Support

AbstractThis article falls within the scope of topology optimization for Additive Manufacturing processes and proposes an alternative strategy to prevent the phenomenon known as the Dripping Effect. The Dripping Effect is when an overhang constraint is imposed on topology optimization processes for Additive Manufacturing and is defined as the formation of oscillatory contour trends within the prescribed threshold angle. Although these drop-like formations constitute local minimizers of the constraint function, they do not provide a printable feature, and, therefore, they neither eliminate the need to form temporary support structures. So far, there has been no general agreement on how to prevent the Dripping Effect, so this work aims to introduce a strategy that effectively prevents it, and that at the same time may be easy to extrapolate to other types of geometric overhang restrictions. This paper provides a study of the origin of the Dripping Effect and gives detailed instructions on how the proposed prevention strategy is applied. In addition, several benchmark examples where the Dripping Effect is prevented are shown.

A hybrid of genetic algorithm and particle swarm optimization for reducing material waste in extrusion-basedadditive manufacturing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ruiliang Feng ◽  
Jingchao Jiang ◽  
Zhichao Sun ◽  
Atul Thakur ◽  
Xiangzhi Wei
Keyword(s):  
Genetic Algorithm ◽  
Particle Swarm Optimization ◽  
Topology Optimization ◽  
Particle Swarm ◽  
Critical Parameters ◽  
Large Set ◽  
Support Structures ◽  
Swarm Optimization ◽  
Content Type ◽  
Fused Deposition

PurposeThe purpose of this paper is to report the design of a lightweight tree-shaped support structure for fused deposition modeling (FDM) three-dimensional (3D) printed models when the printing path is considered as a constraint. Design/methodology/approachA hybrid of genetic algorithm (GA) and particle swarm optimization (PSO) is proposed to address the topology optimization of the tree-shaped support structures, where GA optimizes the topologies of the trees and PSO optimizes the geometry of a fixed tree-topology. Creatively, this study transforms each tree into an approximate binary tree such that GA can be applied to evolve its topology efficiently. Unlike FEM-based methods, the growth of tree branches is based on a large set of FDM 3D printing experiments. FindingsThe hybrid of GA and PSO is effective in reducing the volume of the tree supports. It is shown that the results of the proposed method lead to up to 46.71% material savings in comparison with the state-of-the-art approaches. Research limitations/implicationsThe proposed approach requires a large number of printing experiments to determine the function of the yield length of a branch in terms of a set of critical parameters. For brevity, one can print a small set of tree branches (e.g. 30) on a single platform and evaluate the function, which can be used all the time after that. The steps of GA for topology optimization and those of PSO for geometry optimization are presented in detail. Originality/valueThe proposed approach is useful for the designers and manufacturers to save materials and printing time in fabricating complex models using the FDM technique. It can be adapted to the design of support structures for other additive manufacturing techniques such as Stereolithography and selective laser melting.

Topology Optimization for Additively Manufactured Self-Supporting Axisymmetric Structures

2021 ◽  
Author(s):  
Hak Yong Lee ◽  
Julia D. W. Carroll ◽  
James K. Guest
Keyword(s):  
Topology Optimization ◽  
Pressure Vessels ◽  
Structural Performance ◽  
Support Structures ◽  
Feature Size ◽  
Internal Support ◽  
Gradient Based ◽  
Axisymmetric Structures ◽  
Constraint Approach ◽  
Moving Asymptotes

Abstract This paper discusses the design of axisymmetric structures with self-supporting features that can be additively manufactured without requiring internal support structures. This is motivated by wire-fed additive manufacturing processes, many of which can fabricate designs with enclosed pores that inherently exist in many axisymmetric structures, such as double walled pressure vessels. Although enclosed pores are possible, features that rise at shallow angles from the build plate typically cannot be fabricated without the use of support structures, which require removal and thus are unfavorable in such applications. In this paper, an overhang constraint is applied to ensure that all designed features rise at a designer-prescribed self-supporting angle to eliminate the need for such support structures. This is achieved by coupling the projection-based overhang constraint approach with topology optimization and axisymmetric finite elements whose stiffness is interpolated using Solid Isotropic Material with Penalization (SIMP). Gradients are computed with the adjoint method and the Method of Moving Asymptotes (MMA) is employed as the gradient-based optimizer. Two numerical examples related to a canonical pressure vessel and an optical mirror support structure are used to demonstrate the approach. Solutions are shown to satisfy minimum feature size requirements and designer-prescribed (process dependent) overhang constraint angles, while providing clear and crisp representations of topology. As observed in past works on overhang constraints, a clear trade-off is illustrated between the magnitude of the overhang constraint angle and the structural performance (mass or stiffness), with more strict requirements producing designs with lower performance.

Topology-optimization of Lens Contact Support Structures: PV Value as An Optimization Objective

2019 ◽  
Vol 40 (10) ◽  
pp. 1303-1310
Author(s):  
李一芒 LI Yi-mang ◽  
周子云 ZHOU Zi-yun ◽  
刘永明 LIU Yong-ming
Keyword(s):  
Topology Optimization ◽  
Support Structures

Generating support structures for additive manufacturing with continuum topology optimization methods

2019 ◽  
Vol 25 (2) ◽  
pp. 232-246 ◽  
Author(s):  
Yang Liu ◽  
Zuyu Li ◽  
Peng Wei ◽  
Shikui Chen
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Rapid Development ◽  
Load Condition ◽  
Practical Significance ◽  
Heaviside Function ◽  
Optimal Topology ◽  
Support Structures ◽  
Content Type ◽  
Material Volume

PurposeThe purpose of this paper is to explore the possibility of combining additive manufacturing (AM) with topology optimization to generate support structures for addressing the challenging overhang problem. The overhang problem is considered as a constraint, and a novel algorithm based on continuum topology optimization is proposed.Design/methodology/approachA mathematical model is formulated, and the overhang constraint is embedded implicitly through a Heaviside function projection. The algorithm is based on the Solid Isotropic Material Penalization (SIMP) method, and the optimization problem is solved through sensitivity analysis.FindingsThe overhang problem of the support structures is fixed. The optimal topology of the support structures is developed from a mechanical perspective and remains stable as the material volume of support structures changes, which allows engineers to adjust the material volume to save cost and printing time and meanwhile ensure sufficient stiffness of the support structures. Three types of load conditions for practical application are considered. By discussing the uniform distributive load condition, a compromise result is achieved. By discussing the point load condition, the removal work of support structures after printing is alleviated. By discussing the most unfavorable load condition, the worst collapse situation of the printing model during printing process is sufficiently considered. Numerical examples show feasibility and effectiveness of the algorithm.Research limitations/implicationsThe proposed algorithm involves time-consuming finite element analysis and iterative solution, which increase the computation burden. Only the overhang constraint and the minimum compliance problem are discussed, while other constraints and objective functions may be of interest.Practical implicationsCompared with most of the existing heuristic or geometry-based support-generating algorithms, the proposed algorithm develops support structures for AM from a mechanical perspective, which is necessary for support structures particularly used in AM for mega-scale construction such as architectures and sculptures to ensure printing success and accuracy of the printed model.Social implicationsWith the rapid development of AM, complicated structures result from topology optimization are available for fabrication. The present paper demonstrates a combination of AM and topology optimization, which is the trend of fabricating manner in the future.Originality/valueThis paper remarks the first of attempts to use continuum topology optimization method to generate support structures for AM. The methodology used in this work is theoretically meaningful and conclusions drawn in this paper can be of important instruction value and practical significance.

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