A thermo-mechanical modeling reduction approach for calculating shape distortion in SLM manufacturing for aero engine components

Papadakis, Loucas; Risse, Jeroen; Loizou, Andreas; Bremen, Sebastian; Schrage, Johannes

doi:10.1201/b15961-112

Cited by 13 publications

(5 citation statements)

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“…3 that the residual stress distribution is not uniform, but highly dependent on the scanning strategy. The model described above can be easily extended for building multiple layers.Before a second layer is built, a new powder layer is recoated which takes typically around 10 seconds [13]. During the recoating period, the temperature of the solid cools down to the initial temperature.…”

Section: Resultsmentioning

confidence: 99%

Computationally efficient thermal-mechanical modelling of selective laser melting

Yang

Ayas

2017

AIP Conference Proceedings

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The Selective laser melting (SLM) is a powder based additive manufacturing (AM) method to produce high density metal parts with complex topology. However, part distortions and accompanying residual stresses deteriorates the mechanical reliability of SLM products. Modelling of the SLM process is anticipated to be instrumental for understanding and predicting the development of residual stress field during the build process. However, SLM process modelling requires determination of the heat transients within the part being built which is coupled to a mechanical boundary value problem to calculate displacement and residual stress fields. Thermal models associated with SLM are typically complex and computationally demanding. In this paper, we present a simple semi-analytical thermal-mechanical model, developed for SLM that represents the effect of laser scanning vectors with line heat sources. The temperature field within the part being build is attained by superposition of temperature field associated with line heat sources in a semi-infinite medium and a complimentary temperature field which accounts for the actual boundary conditions. An analytical solution of a line heat source in a semi-infinite medium is first described followed by the numerical procedure used for finding the complimentary temperature field. This analytical description of the line heat sources is able to capture the steep temperature gradients in the vicinity of the laser spot which is typically tens of micrometers. In turn, semi-analytical thermal model allows for having a relatively coarse discretisation of the complimentary temperature field. The temperature history determined is used to calculate the thermal strain induced on the SLM part. Finally, a mechanical model governed by elastic-plastic constitutive rule having isotropic hardening is used to predict the residual stresses.

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Section: Resultsmentioning

confidence: 99%

Computationally efficient thermal-mechanical modelling of selective laser melting

Yang

Ayas

2017

AIP Conference Proceedings

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“…However, once scanning of the layer is completed, the top surface ∂V top shifts up such that the modelled domain is extended, i.e., a new layer of finite difference cells is introduced. During the SLM process, prior to the laser scanning of a layer, a new layer of powder is laid down with a recoater which typically takes around 10 s [46]. Given the high conductivity of a solid metal, during the powder recoating, solid can cool down to its initial temperature.…”

Section: Building Multiple Layersmentioning

confidence: 99%

A semi-analytical thermal modelling approach for selective laser melting

Yang

Knol

Keulen

et al. 2018

Additive Manufacturing

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Selective laser melting (SLM) wherein a metal part is built in a layer-by-layer manner in a powder bed is a promising and versatile way for manufacturing components with complex geometry. However, components built by SLM suffer from substantial deformation of the part and residual stresses. Residual stresses arise due to temperature gradients inherent to the process and the accompanying deformation. It is well known that the SLM process parameters and the laser scanning strategy have a substantial effect on the temperature transients of the part and henceforth on the degree of deformations and residual stresses. In order to provide a tool to investigate this relation, a semi-analytical thermal model of the SLM process is presented which determines the temperature evolution in a 3D part by way of representing the moving laser spot with a finite number of point heat sources. The solution of the thermal problem is constructed from the superposition of analytical solutions for point sources which are known in semi-infinite space and complimentary numerical/analytical fields to impose the boundary conditions. The unique property of the formulation is that numerical discretisation of the problem domain is decoupled from the steep gradients in the temperature field associated with localised laser heat input. This enables accurate and numerically tractable simulation of the process. The predictions of this semi-analytical model are validated by experiments and the exact solution known for a simple thermal problem. Simulations for building a complete layer using two different scanning patterns and subsequently building of multiple layers with constant and rotating scanning patterns in successive layers are performed. The computational efficiency of the semi-analytical tool is assessed which demonstrates its potential to gain physical insight in the full SLM process with acceptable computational costs.

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“…Similarly, the adaptive mesh‐coarsening algorithm based on FEM was used by Ince and coworkers [ 12 ] to significantly save the calculation time to predict the stress field in AM process, and the simulation results were in good agreement with the experimental measurements. Papadakis et al [ 13 ] proposed several methods to simplify the thermal analysis process. The detailed loading process of moving heat source was omitted to effectively reduce the calculation time.…”

Section: Introductionmentioning

confidence: 99%

Efficient Simulation Methods for Thermal‐Mechanical Coupled Analysis and Rapid Residual Distortion Prediction of Laser Melting Deposition Process

Cao

Duan

Luo

2021

steel research int.

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Herein, an improved thermal‐mechanical coupled analysis is used to increase the calculation efficiency of the detailed laser melting deposition (LMD) process. By optimizing the loading process of the laser heat source and lumping several deposited layers into an equivalent numerical layer, the efficiency is significantly improved. The calculation time is saved by 85% when lumping six layers. Compared with the experimental data, the minimum deviation of predicted maximum distortion reaches 3.2% when lumping four layers. A multiscale method is proposed to predict the distortion result of the large‐sized part efficiently. In this method, the optimal heights of equivalent numerical layers are explored. The comparisons with the experimental result show that the optimal heights of equivalent numerical layers are 1 and 1.5 mm in view of accuracy and efficiency. Based on the multiscale method, the residual distortion of the substrate after depositing a large‐sized eight‐layer line deposition structure is accurately predicted. The deviations of the maximum distortion predicted by the improved thermal‐mechanical coupled simulation and the multiscale method are 3.26% and 6.12%, respectively. Moreover, the calculation time of the latter is 98.8% less than that of the former.

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A thermo-mechanical modeling reduction approach for calculating shape distortion in SLM manufacturing for aero engine components

Cited by 13 publications

References 0 publications

Computationally efficient thermal-mechanical modelling of selective laser melting

Computationally efficient thermal-mechanical modelling of selective laser melting

A semi-analytical thermal modelling approach for selective laser melting

Efficient Simulation Methods for Thermal‐Mechanical Coupled Analysis and Rapid Residual Distortion Prediction of Laser Melting Deposition Process

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