Conceptual design of AM components using layout and geometry optimization

Linwei He,Matthew Gilbert,Thomas Johnson,Tom Pritchard

doi:10.1016/j.camwa.2018.07.012

Linwei He, Matthew Gilbert + Show 2 more

Open Access

https://doi.org/10.1016/j.camwa.2018.07.012

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Abstract

In this paper truss layout optimization is used in conjunction with geometry optimization to provide the basis for a powerful conceptual design tool for additively manufactured (AM) components, particularly useful when the degree of design freedom is high. With layout optimization the design domain is discretized using a grid of nodes which are interconnected with discrete line elements, forming a ‘ground structure’. Linear optimization can then be used to identify the subset of elements forming the minimum volume structure required to carry the applied loading. A nonlinear geometry optimization step, which involves adjusting the positions of the nodes, can subsequently be undertaken to simplify and improve the solution. Simple geometrical rules can then be used to automatically transform a line element layout into a 3D continuum, ready for validation and/or manufacture. Various extensions to the basic method are described in the paper, including AM build direction constraints and techniques to permit user-interaction with candidate designs, which has been found to be invaluable at the conceptual design stage. Finally the approach described is applied to a range of design problems, including the redesign of an airbrake hinge for the Bloodhound Supersonic Car.

Highlights

Additive manufacturing (AM, or ‘3D printing’) techniques are developing rapidly, and are sufficiently mature to be used to produce high value components
The solutions obtained via layout optimization can be complex in form, many such forms can readily be manufactured via additively manufactured (AM), leading to renewed interest in the method [5,6,7]
Note that many of the examples considered are, for sake of simplicity, 2D forms, which could in many cases be additively manufactured without build direction constraints in practice, the methods described are applicable to more complex 3D forms where build direction constraints are potentially useful

Summary

Introduction

Additive manufacturing (AM, or ‘3D printing’) techniques are developing rapidly, and are sufficiently mature to be used to produce high value components. Topology optimization approaches can be computationally expensive and often require labour intensive post-processing in order to realize a practical component. An alternative is to use numerical layout optimization; employing a ground structure [2] to generate least-weight truss designs, which are usually found to be very structurally efficient when the degree of design freedom is high. Using this method, linear programming (LP) can be used to obtain solutions, which ensures the process is robust and computationally efficient, especially when adaptive solution strategies are employed [3,4]. Automatic rationalization techniques (e.g., [8]) can potentially help increase the practicality of a design

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