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Classification and analysis of common simplifications in part-scale thermal modelling of metal additive manufacturing processes

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

Computational process modelling of metal additive manufacturing has gained significant research attention in recent past. The cornerstone of many process models is the transient thermal response during the AM process. Since deposition-scale modelling of the thermal conditions in AM is computationally expensive, spatial and temporal...

journal article 2023

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Overheating control in additive manufacturing using a 3D topology optimization method and experimental validation

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

Overheating is a major issue especially in metal Additive Manufacturing (AM) processes, leading to poor surface quality, lack of dimensional precision, inferior performance and/or build failures. A 3D density-based topology optimization (TO) method is presented which addresses the issue of local overheating during metal AM. This is achieved...

journal article 2023

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Holistic computational design within additive manufacturing through topology optimization combined with multiphysics multi-scale materials and process modelling

Bayat, Mohamad (author), Zinovieva, Olga (author), Ferrari, Federico (author), Ayas, C. (author), Langelaar, Matthijs (author), Spangenberg, Jon (author), Salajeghe, Roozbeh (author), Poulios, Konstantinos (author), Mohanty, Sankhya (author), Sigmund, Ole (author), Hattel, Jesper (author)

Additive manufacturing (AM) processes have proven to be a perfect match for topology optimization (TO), as they are able to realize sophisticated geometries in a unique layer-by-layer manner. From a manufacturing viewpoint, however, there is a significant likelihood of process-related defects within complex geometrical features designed by TO...

review 2023

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Design for material properties of additively manufactured metals using topology optimization

Mishra, V. (author), Ayas, C. (author), Langelaar, Matthijs (author)

In metal Additive Manufacturing (AM), the deposited material is subjected to a series of heating and cooling cycles. The locally occurring temperature extremes and cooling rates determine solid-state phase fractions, material microstructure, texture, and ultimately the local material properties. As the shape of a part determines the local...

journal article 2023

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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

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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

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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

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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

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Topology Optimization for additive manufacturing with distortion constraints

Misiun, Grzegorz (author), van de Ven, E.A. (author), Langelaar, Matthijs (author), Geijselaers, Hubert (author), van Keulen, A. (author), van den Boogaard, Ton (author), Ayas, C. (author)

An important cause of failure in powder bed additive manufacturing is the distortion of the part due to thermal shrinkage during printing and the relaxation of residual stresses after its release from the base plate. In this paper, Additive Manufacturing simulations are coupled with Topology Optimization in order to generate designs that are...

journal article 2021

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Accessibility of support structures in topology optimization for additive manufacturing

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

Additive manufacturing (AM) and topology optimization (TO) have a synergetic relation, as AM can produce complex TO designs, and TO provides high-performance parts that utilize the form freedom provided by AM. Recently, TO has been tailored more toward AM with the inclusion of the minimum allowable overhang angle as a design constraint:...

journal article 2021

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Topology optimisation for large-scale additive manufacturing: generating designs tailored to the deposition nozzle size

Fernández, E. (author), Ayas, C. (author), Langelaar, Matthijs (author), Duysinx, P. (author)

Additive Manufacturing (AM) processes intended for large-scale components deposit large volumes of material to shorten process duration. This reduces the resolution of the AM process, which is typically defined by the deposition nozzle size. If the resolution limitation is not considered when designing for Large-Scale Additive Manufacturing ...

journal article 2021

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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

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Fast Detection of Heat Accumulation in Powder Bed Fusion Using Computationally Efficient Thermal Models

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

The powder bed fusion (PBF) process is a type of Additive Manufacturing (AM) technique which enables fabrication of highly complex geometries with unprecedented design freedom. However, PBF still suffers from manufacturing constraints which, if overlooked, can cause various types of defects in the final part. One such constraint is the local...

journal article 2020

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Improving the manufacturability of metal AM parts

Sinico, Mirko (author), Ranjan, R. (author), Moshiri, Mandana (author), Ayas, C. (author), Langelaar, Matthijs (author), van Keulen, A. (author), Dewulf, Wim (author), Witvrouw, Ann (author)

Numerous challenges of additive manufacturing (AM) are tackled in the European Horizon 2020 project PAM^2 by studying and linking every step of the AM process cycle. For example, PAM^2 researchers from the design, processing and application side have collaborated in this work to optimise the manufacturability of metal AM parts using an improved...

journal article 2019

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On process-step parallel computability and linear superposition of mechanical responses in additive manufacturing process simulation

Munro, D.P. (author), Ayas, C. (author), Langelaar, Matthijs (author), van Keulen, A. (author)

We study linearity assumptions in the transient macroscale mechanical aspect of additive manufacturing (AM) process simulation. Linearity assumptions are often resorted to in combination with calibrated inelastic deformation components to arrive at computationally tractable yet reasonably accurate AM process models. We point out that...

journal article 2019

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A mold insert case study on topology optimized design for additive manufacturing

Sinico, M. (author), Ranjan, R. (author), Moshiri, M. (author), Ayas, C. (author), Langelaar, Matthijs (author), Witvrouw, A. (author), van Keulen, A. (author), Dewulf, W. (author)

The Additive Manufacturing (AM) of injection molding inserts has gained popularity during recent years primarily due to the reduced design-to-production time and form freedom offered by AM. In this paper, Topology Optimization (TO) is performed on a metallic mold insert which is to be produced by the Laser Powder Bed Fusion (LPBF) technique....

conference paper 2019

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New support structures for reduced overheating on downfacing regions of direct metal printed parts

Paggi, Umberto (author), Ranjan, R. (author), Thijs, Lore (author), Ayas, C. (author), Langelaar, Matthijs (author), van Keulen, A. (author), van Hooreweder, Brecht (author)

In Laser Powder Bed Fusion (LPBF), the downfacing surfaces usually have increased surface roughness and reduced dimensional accuracy due to local overheating and warpage. To partially overcome this a new supporting structure is developed in this study, namely the contactless support. This is a thin blade parallel to the critical area which...

conference paper 2019

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Topology optimization with overhang filter considering accessibility of supports

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

abstract 2018

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Towards design for precision additive manufacturing: A simplified approach for detecting heat accumulation

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

conference paper 2018

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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