document

Optimizing front metallization patterns: Efficiency with aesthetics in free-form solar cells

Gupta, D.K. (author), Langelaar, Matthijs (author), Barink, M (author), van Keulen, A. (author)

Free-form solar cells are cells of unconventional shapes (e.g. hexagonal, leaf-shaped etc). Their flexible shape adds to the aesthetics of the surroundings as well as allows to place them over objects where conventional solar cells might not fit. Evidently, these cells need to be efficient as well, and one of the important factors that...

journal article 2016

document

A unified aggregation and relaxation approach for stress-constrained topology optimization

Verbart, A. (author), Langelaar, Matthijs (author), van Keulen, A. (author)

In this paper, we propose a unified aggregation and relaxation approach for topology optimization with stress constraints. Following this approach, we first reformulate the original optimization problem with a design-dependent set of constraints into an equivalent optimization problem with a fixed design-independent set of constraints. The next...

journal article 2017

document

Topology optimization for submerged buoyant structures

Picelli, R. (author), van Dijk, R. (author), Vicente, W.M. (author), Pavanello, R. (author), Langelaar, Matthijs (author), van Keulen, A. (author)

This paper presents an evolutionary structural topology optimization method for the design of completely submerged buoyant modules with design-dependent fluid pressure loading. This type of structure is used to support offshore rig installation and pipeline transportation at all water depths. The proposed optimization method seeks to identify...

journal article 2017

document

Integrating topology optimization in precision motion system design for optimal closed-loop control performance

van der Veen, G.J. (author), Langelaar, Matthijs (author), van der Meulen, Stan (author), Laro, Dick (author), Aangenent, Wouter (author), van Keulen, A. (author)

In pursuit of better accuracy, higher speed and larger scale, manufacturers of high-performance devices increasingly rely on components which have been designed with a multidisciplinary approach from the outset. In the context of motion systems, this means that for instance structural mechanics, control engineering and thermal analysis are...

journal article 2017

document

Continuous front propagation-based overhang control for topology optimization with additive manufacturing

van de Ven, E.A. (author), Maas, Robert (author), Ayas, C. (author), Langelaar, Matthijs (author), van Keulen, A. (author)

Additive manufacturing enables the nearly uncompromised production of optimized topologies. However, due to the overhang limitation, some designs require a large number of supporting structures to enable manufacturing. Because these supports are costly to build and difficult to remove, it is desirable to find alternative designs that do not...

journal article 2018

document

Space-time topology optimization for additive manufacturing: Concurrent optimization of structural layout and fabrication sequence

Wang, W. (author), Munro, D.P. (author), Wang, C.C. (author), van Keulen, A. (author), Wu, J. (author)

The design of optimal structures and the planning of (additive manufacturing) fabrication sequences have been considered typically as two separate tasks that are performed consecutively. In the light of recent advances in robot-assisted (wire-arc) additive manufacturing which enable addition of material along curved surfaces, we present a...

journal article 2019

document

An interface-enriched generalized finite element method for level set-based topology optimization

van den Boom, S.J. (author), Zhang, J. (author), van Keulen, A. (author), Aragon, A.M. (author)

During design optimization, a smooth description of the geometry is important, especially for problems that are sensitive to the way interfaces are resolved, e.g., wave propagation or fluid-structure interaction. A level set description of the boundary, when combined with an enriched finite element formulation, offers a smoother description...

journal article 2020

document

Overhang control based on front propagation in 3D topology optimization for additive manufacturing

van de Ven, E.A. (author), Maas, Robert (author), Ayas, C. (author), Langelaar, Matthijs (author), van Keulen, A. (author)

It is attractive to combine topology optimization (TO) with additive manufacturing (AM), due to the design freedom provided by AM, and the increased performance that can be achieved with TO. One important aspect is to include the design rules associated with the process restrictions of AM to prevent the requirement of relatively large support...

journal article 2020

document

Efficient limitation of resonant peaks by topology optimization including modal truncation augmentation

Delissen, A.A.T.M. (author), van Keulen, A. (author), Langelaar, Matthijs (author)

In many engineering applications, the dynamic frequency response of systems is of high importance. In this paper, we focus on limiting the extreme values in frequency response functions, which occur at the eigenfrequencies of the system, better known as resonant peaks. Within an optimization, merely sampling the frequency range and limiting the...

journal article 2020

document

Simultaneous optimization of topology and layout of modular stiffeners on shells and plates

Bakker, Coen (author), Zhang, L. (author), Higginson, Kristie (author), van Keulen, A. (author)

Stiffened shells and plates are widely used in engineering. Their performance is highly influenced by the arrangement, or layout, of stiffeners on the base shell or plate and the geometric features, or topology, of these stiffeners. Moreover, modular design is beneficial, since it allows for increased quality control and mass production. In...

journal article 2021

document

Overhang control in topology optimization: a comparison of continuous front propagation-based and discrete layer-by-layer overhang control

van de Ven, E.A. (author), Maas, Robert (author), Ayas, C. (author), Langelaar, Matthijs (author), van Keulen, A. (author)

Although additive manufacturing (AM) allows for a large design freedom, there are some manufacturing limitations that have to be taken into consideration. One of the most restricting design rules is the minimum allowable overhang angle. To make topology optimization suitable for AM, several algorithms have been published to enforce a minimum...

journal article 2021

document

Simultaneous topology and deposition direction optimization for Wire and Arc Additive Manufacturing

Mishra, V. (author), Ayas, C. (author), Langelaar, Matthijs (author), van Keulen, A. (author)

A remarkable elastic anisotropy in plates of austenitic stainless steel produced by the Wire and Arc Additive Manufacturing process is recently reported. The Young's modulus depends on the angle of orientation with respect to the material deposition direction. Here, for the first time, this anisotropy is exploited to maximize structural...

journal article 2022

document

A simple and versatile topology optimization formulation for flexure synthesis

Koppen, S. (author), Langelaar, Matthijs (author), van Keulen, A. (author)

High-tech equipment critically relies on flexures for precise manipulation and measurement. Through elastic deformation, flexures offer extreme position repeatability within a limited range of motion in their degrees of freedom, while constraining motion in the degrees of constraint. Topology optimization proves a prospective tool for the...

journal article 2022

document

Efficient multi-partition topology optimization

Koppen, S. (author), Langelaar, Matthijs (author), van Keulen, A. (author)

In topology optimization, the state of structures is typically obtained by numerically evaluating a discretized PDE-based model. The degrees of freedom of such a model can be partitioned in free and prescribed sets to define the boundary conditions. A multi-partition problem involves multiple partitions of the same discretization, typically...

journal article 2022

document

Realization and assessment of metal additive manufacturing and topology optimization for high-precision motion systems

Delissen, A.A.T.M. (author), Boots, Elwin (author), Laro, Dick (author), Kleijnen, Harry (author), van Keulen, A. (author), Langelaar, Matthijs (author)

The design of high-precision motion stages, which must exhibit high dynamic performance, is a challenging task. Manual design is difficult, time-consuming, and leads to sub-optimal designs that fail to fully exploit the extended geometric freedom that additive manufacturing offers. By using topology optimization and incorporating all...

journal article 2022

document

Design for drainability in density-based topology optimization

Giele, R.J.P. (author), van Keulen, A. (author), Langelaar, Matthijs (author)

Topology optimization methods improve the structural performance of components. However, in food processing, medical, high-precision, and other industries' designs should also fulfil the requirement of being cleanable. An important aspect of cleanability is drainability, which entails that fluids can always run off the structure under just...

journal article 2022

document

A stress-based criterion to identify and control intersections in 2D compliance minimization topology optimization

Mishra, V. (author), Ayas, C. (author), Langelaar, Matthijs (author), van Keulen, A. (author)

Topology optimization typically generates designs that exhibit significant geometrical complexity, which can pose difficulties for manufacturing and assembly. The number of occurrences of an important design feature, in particular intersections, increases with geometrical complexity. Intersections are essential for load transfer in many...

journal article 2022

document

Controlling local overheating in topology optimization for additive manufacturing

Ranjan, R. (author), Ayas, C. (author), Langelaar, Matthijs (author), van Keulen, A. (author)

A novel constraint to prevent local overheating is presented for use in topology optimization (TO). The very basis for the constraint is the Additive Manufacturing (AM) process physics. AM enables fabrication of highly complex topologically optimized designs. However, local overheating is a major concern especially in metal AM processes...

journal article 2022

document

A level set-based interface-enriched topology optimization for the design of phononic crystals with smooth boundaries

van den Boom, S.J. (author), Abedi, Reza (author), van Keulen, A. (author), Aragon, A.M. (author)

Phononic crystals can be designed to show band gaps—ranges of frequencies whose propagation is strongly attenuated in the material. In essence, their working principle is based on destructive interference of waves reflecting from the periodic arrangement of material interfaces (i.e., Bragg scattering). Consequently, capturing accurately the...

journal article 2023

document

Topology optimization of geometrically nonlinear structures using reduced-order modeling

Zhang, L. (author), Zhang, Y. (author), van Keulen, A. (author)

High computational costs are encountered in topology optimization problems of geometrically nonlinear structures since intensive use has to be made of incremental-iterative finite element simulations. To alleviate this computational intensity, reduced-order models (ROMs) are explored in this paper. The proposed method targets ROM bases...

journal article 2023