Part consolidation for additive manufacturing: a multi‐layered topology optimization approach

2021 ◽  
Author(s):  
Luke Crispo ◽  
Il Yong Kim
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Optimization Approach ◽  
Part Consolidation

Boundary Slope Control in Topology Optimization for Additive Manufacturing: For Self-Support and Surface Roughness

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Cunfu Wang ◽  
Xiaoping Qian ◽  
William D. Gerstler ◽  
Jeff Shubrooks
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Topology Optimization ◽  
Additive Manufacturing ◽  
Density Gradient ◽  
Transfer Efficiency ◽  
Global Constraints ◽  
Optimization Approach ◽  
Heat Transfer Efficiency ◽  
Boundary Slope

This paper studies how to control boundary slope of optimized parts in density-based topology optimization for additive manufacturing (AM). Boundary slope of a part affects the amount of support structure required during its fabrication by additive processes. Boundary slope also has a direct relation with the resulting surface roughness from the AM processes, which in turn affects the heat transfer efficiency. By constraining the minimal boundary slope, support structures can be eliminated or reduced for AM, and thus, material and postprocessing costs are reduced; by constraining the maximal boundary slope, high-surface roughness can be attained, and thus, the heat transfer efficiency is increased. In this paper, the boundary slope is controlled through a constraint between the density gradient and the given build direction. This allows us to explicitly control the boundary slope through density gradient in the density-based topology optimization approach. We control the boundary slope through two single global constraints. An adaptive scheme is also proposed to select the thresholds of these two boundary slope constraints. Numerical examples of linear elastic problem, heat conduction problem, and thermoelastic problems demonstrate the effectiveness and efficiency of the proposed formulation in controlling boundary slopes for additive manufacturing. Experimental results from metal 3D printed parts confirm that our boundary slope-based formulation is effective for controlling part self-support during printing and for affecting surface roughness of the printed parts.

scholarly journals Continuous Fiber Angle Topology Optimization for Polymer Composite Deposition Additive Manufacturing Applications

Fibers ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 14 ◽  
Author(s):  
Delin Jiang ◽  
Robert Hoglund ◽  
Douglas Smith
Keyword(s):  
Mechanical Properties ◽  
Topology Optimization ◽  
Additive Manufacturing ◽  
Carbon Fiber ◽  
Polymer Composite ◽  
Fiber Reinforcement ◽  
Fiber Direction ◽  
Optimization Approach ◽  
Continuous Fiber ◽  
Fiber Angle

Mechanical properties of parts produced with polymer deposition additive manufacturing (AM) depend on the print bead direction, particularly when short carbon-fiber reinforcement is added to the polymer feedstock. This offers a unique opportunity in the design of these structures since the AM print path can potentially be defined in a direction that takes advantage of the enhanced stiffness gained in the bead and, therefore, fiber direction. This paper presents a topology optimization approach for continuous fiber angle optimization (CFAO), which computes the best layout and orientation of fiber reinforcement for AM structures. Statically loaded structures are designed for minimum compliance where the adjoint variable method is used to compute design derivatives, and a sensitivity filter is employed to reduce the checkerboard effect. The nature of the layer-by-layer approach in AM is given special consideration in the algorithm presented. Examples are provided to demonstrate the applicability of the method in both two and three dimensions. The solution to our two dimensional problem is then printed with a fused filament fabrication (FFF) desktop printer using the material distribution results and a simple infill method which approximates the optimal fiber angle results using a contour-parallel deposition strategy. Mechanical stiffness testing of the printed parts shows improved results as compared to structures designed without accounting for the direction of the composite structure. Results show that the mechanical properties of the final FFF carbon fiber/polymer composite printed parts are greatly influenced by the print direction, and optimized material orientation tends to align with the imposed force direction to minimize the compliance.

A Multi-Scale Topology Optimization Approach for Optimal Macro-Layout and Local Grading of TPMS-Based Lattices

2021 ◽  
Author(s):  
Niclas Strömberg
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Local Density ◽  
Bulk Material ◽  
Transversely Isotropic ◽  
Benchmark Problems ◽  
Optimization Approach ◽  
Lattice Structures ◽  
Efficient Design ◽  
Multi Scale

Abstract The use of lattice structures in design for additive manufacturing has quickly emerged as a popular and efficient design alternative for creating innovative multifunctional lightweight solutions. In particular, the family of triply periodic minimal surfaces (TPMS) studied in detail by Schoen for generating frame-or shell-based lattice structures seems extra promising. In this paper a multi-scale topology optimization approach for optimal macro-layout and local grading of TPMS-based lattice structures is presented. The approach is formulated using two different density fields, one for identifying the macro-layout and another one for setting the local grading of the TPMS-based lattice. The macro density variable is governed by the standard SIMP formulation, but the local one defines the orthotropic elasticity of the element following material interpolation laws derived by numerical homogenization. Such laws are derived for frame- and shell-based Gyroid, G-prime and Schwarz-D lattices using transversely isotropic elasticity for the bulk material. A nice feature of the approach is that the lower and upper additive manufacturing limits on the local density of the TMPS-based lattices are included properly. The performance of the approach is excellent, and this is demonstrated by solving several three-dimensional benchmark problems, e.g., the optimal macro-layout and local grading of Schwarz-D lattice for the established GE-bracket is identified using the presented approach.

scholarly journals Optimization of Brake Calipers Using Topology Optimization for Additive Manufacturing

2021 ◽  
Vol 11 (4) ◽  
pp. 1437
Author(s):  
Evangelos Tyflopoulos ◽  
Mathias Lien ◽  
Martin Steinert
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Optimization Procedure ◽  
Optimization Approach ◽  
Design Flexibility ◽  
Current State ◽  
3D Printed ◽  
Removal Processes ◽  
Material Layout

The weight optimization of a structure can be conducted by using fewer and downsized components, applying lighter materials in production, and removing unwanted material. Topology optimization (TO) is one of the most implemented material removal processes. In addition, when it is oriented towards additive manufacturing (AM), it increases design flexibility. The traditional optimization approach is the compliance optimization, where the material layout of a structure is optimized by minimizing its overall compliance. However, TO, in its current state of the art, is mainly used for design inspiration and not for manufacturing due to design complexities and lack of accuracy of its design solutions. The authors, in this research paper, explore the benefits and the limitations of the TO using as a case study the housings of a front and a rear brake caliper. The calipers were optimized for weight reduction by implementing the aforementioned optimization procedure. Their housings were topologically optimized, partially redesigned, prepared for 3D printing, validated, and 3D printed in titanium using selective laser melting (SLM). The weight of the optimized calipers reduced by 41.6% compared to commercial calipers. Designers interested in either TO or in automotive engineering can exploit the findings in this paper.

Topology Optimization of Self-Supported Enclosed Voids for Additive Manufacturing

2021 ◽  
Author(s):  
Cunfu Wang
Keyword(s):  
Heat Flux ◽  
Topology Optimization ◽  
Additive Manufacturing ◽  
Heat Conduction Problem ◽  
Boundary Representation ◽  
Maximum Temperature ◽  
Optimization Approach ◽  
Optimized Design ◽  
Surface Slope ◽  
Conductive Materials

Abstract The paper proposes a heat-flux based topology optimization approach to design self-supported enclosed voids for additive manufacturing. The enclosed overhangs that require supports in additive manufacturing are removed from the optimized design by constraining the maximum temperature of a pseudo heat conduction problem. In the pseudo problem, heat flux is applied on the non-self-supported open and enclosed surfaces. Since the density-based topology optimization involves no explicit boundary representation, we impose such surface slope dependent heat flux through a domain integral of a Heaviside projected density gradient. In addition, the solid materials and the void materials in the pseudo problem are assumed to be thermally insulating and conductive, respectively. As such, heat flux on the open surfaces can be successfully conducted to external heat sink through the void (or conductive) materials. However, heat flux on the non-self-supported enclosed surfaces is isolated by the solid (or insulating) materials and thus leads to locally high temperature. Hence, by limiting the maximum temperature of the pseudo problem, self-supported enclosed voids can be achieved, and the slope of the open surfaces would not be affected. Numerical examples are presented to demonstrate the validity and effectiveness of the proposed approach in the design of self-supported enclosed voids.

Lessons Learnt from a National Competition on Structural Optimization and Additive Manufacturing

2020 ◽  
Vol 1 (1) ◽  
pp. 151-159
Author(s):  
Yulin Xiong ◽  
Dingwen Bao ◽  
Xin Yan ◽  
Tao Xu ◽  
Yi Min Xie
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Structural Optimization ◽  
Optimization Approach ◽  
Loading Test ◽  
Highly Efficient ◽  
Evolutionary Structural Optimization ◽  
National Competition ◽  
Optimal Material ◽  
Manufacturing Technologies

Background:: As an advanced design technique, topology optimization has received much attention over the past three decades. Topology optimization aims at finding an optimal material distribution in order to maximize the structural performance while satisfying certain constraints. It is a useful tool for the conceptional design. At the same time, additive manufacturing technologies have provided unprecedented opportunities to fabricate intricate shapes generated by topology optimization. Objective:: To design a highly efficient structure using topology optimization and to fabricate it using additive manufacturing. Method:: The bi-directional evolutionary structural optimization (BESO) technique provides the conceptional design, and the topology-optimized result is post-processed to obtain smooth structural boundaries. Results:: We have achieved a highly efficient and elegant structural design which won the first prize in a national competition in China on design optimization and additive manufacturing. Conclusion:: In this paper, we present an effective topology optimization approach to maximize the structural load-bearing capacity and establish a procedure to achieve efficient and elegant structural designs. : In the loading test of the final competition, our design carried the highest loading and won the first prize in the competition, which demonstrates the capability of BESO in engineering applications.

Boundary Slope Control in Topology Optimization for Additive Manufacturing

2018 ◽  
Author(s):  
Cunfu Wang ◽  
Xiaoping Qian ◽  
William D. Gerstler ◽  
Jeff Shubrooks
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Topology Optimization ◽  
Additive Manufacturing ◽  
Density Gradient ◽  
Heat Conduction Problem ◽  
Transfer Efficiency ◽  
Optimization Approach ◽  
Heat Transfer Efficiency ◽  
Boundary Slope

The paper studies how to control boundary slope of optimized parts in density-based topology optimization for additive manufacturing (AM). Boundary slope of a part affects the amount of support structure required during its fabrication by additive processes. Boundary slope also has direct relation with the resulting surface roughness from the AM processes, which in turn affects the heat transfer efficiency. By constraining the minimal boundary slope, support structures can be eliminated or reduced for AM, and thus material and post-processing costs are reduced; by constraining the maximal boundary slope, high surface roughness can be attained, and thus the heat transfer efficiency is increased. In this paper, the boundary slope is controlled through a constraint between the density gradient and the given build direction. This allows us to explicitly control the boundary slope through density gradient in the density-based topology optimization approach. We control the boundary slope through a single global constraint. Numerical examples on heat conduction problem, and coupled 2D and 3D thermoelastic problems demonstrate the effectiveness and efficiency of the proposed formulation in controlling boundary slopes for additive manufacturing.

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