Thermomechanical finite element simulations of selective electron beam melting processes: performance considerations

Riedlbauer, Daniel; Steinmann, Paul; Mergheim, Julia

doi:10.1007/s00466-014-1026-0

Cited by 44 publications

(22 citation statements)

References 22 publications

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“…General coupled thermo-mechanical analyses of SLM have been reported by several authors [16][17][18][19], but these did not examine in detail the effects of laser scan strategy and are mainly focused on developing modelling techniques. Observations from such simulations have included the reporting of an asymmetric melt-pool and that the largest stress component was generated parallel to the scanning direction, agreeing with previous experimental studies [14].…”

Section: Introductionmentioning

confidence: 99%

Understanding the effect of laser scan strategy on residual stress in selective laser melting through thermo-mechanical simulation

Parry

Ashcroft

Wildman

2016

Additive Manufacturing

407

287

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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. Abstract: Selective laser melting (SLM) is an attractive technology, enabling the manufacture of customised, complex metallic designs, with minimal wastage. However, uptake by industry is currently impeded by several technical barriers, such as the control of residual stress, which have a detrimental effect on the manufacturability and integrity of a component. Indirectly, these impose severe design restrictions and reduce the reliability of components, driving up costs. This paper uses a thermo-mechanical model to better understand the effect of laser scan strategy on the generation of residual stress in SLM. A complex interaction between transient thermal history and the build-up of residual stress has been observed in the two laser scan strategies investigated. The temperature gradient mechanism was discovered for the creation of residual stress. The greatest stress component was found to develop parallel to the scan vectors, creating an anisotropic stress distribution in the part. The stress distribution varied between laser scan strategies and the cause has been determined by observing the thermal history during scanning. Using this, proposals are suggested for designing laser scan strategies used in SLM. Abstract:Selective laser melting (SLM) is an attractive technology, enabling the manufacture of customised, complex metallic designs, with minimal wastage. However, uptake by industry is currently impeded by several technical barriers, such as the control of residual stress, which have a detrimental effect on the manufacturability and integrity of a component. Indirectly, these impose severe design restrictions and reduce the reliability of components, driving up costs. This paper uses a thermomechanical model to better understand the effect of laser scan strategy on the generation of residual stress in SLM. A complex interaction between transient thermal history and the build-up of residual stress has been observed in the two laser scan strategies investigated. The temperature gradient mechanism was discovered for the creation of residual stress. The greatest stress component was found to develop parallel to the scan vectors, creating an anisotropic stress distribution in the part. The stress distribution varied between laser scan strategies and the cause has been determined by observing the thermal history during scanning. Using this, proposals are suggested for designing laser scan strategies used in SLM. Nomenclature:Specific

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Section: Introductionmentioning

confidence: 99%

Understanding the effect of laser scan strategy on residual stress in selective laser melting through thermo-mechanical simulation

Parry

Ashcroft

Wildman

2016

Additive Manufacturing

407

287

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“…Problems with localized nonhomogeneous material properties are of great interest in engineering [3,4,5,8,9,10,11,12,14,15,16,22,23,24,25,26,27]. In such problems, the varying physical properties between the different regions result in potentially large modeling differences.…”

Section: Introductionmentioning

confidence: 99%

“…In many instances, a material which comprises a relatively small portion of the domain may feature significantly more complex physics and, therefore, it may require a higher mesh resolution than in the remainder of the domain. Common examples of such problems with high industrial interest are thermal problems in additive manufacturing (where the nonlinear phase transformation phenomena occur only along a thin strip on the top of the domain) [3,10,11,12,14,15,16,22,23,24,25,26,27], or fluid flow problems through immersed membranes (where the flow properties change inside a subregion of the domain) [17,18,19,21]. A simple diagram of such a physical situation is shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

A Fat boundary-type method for localized nonhomogeneous material problems

Viguerie

Bertoluzza²,

Auricchio

2020

Computer Methods in Applied Mechanics and Engineering

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Problems with localized nonhomogeneous material properties arise frequently in many applications and are a well-known source of difficulty in numerical simulations. In certain applications (including additive manufacturing), the physics of the problem may be considerably more complicated in relatively small portions of the domain, requiring a significantly finer local mesh compared to elsewhere in the domain. This can make the use of a uniform mesh numerically unfeasible. While nonuniform meshes can be employed, they may be challenging to generate (particularly for regions with complex boundaries) and more difficult to precondition. The problem becomes even more prohibitive when the region requiring a finer-level mesh changes in time, requiring the introduction of refinement and derefinement techniques. To address the aforementioned challenges, we employ a technique related to the Fat boundary method [1,2,20] as a possible alternative. We analyze the proposed methodology from a mathematical point of view and validate our findings on two-dimensional numerical tests.

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“…The scheme allows to split the original monolithic thermomechanical problem (1) into two smaller subproblems, called thermal and mechanical problem. In comparison with the monolithic problem less computing time is needed to solve both subproblems [4]. Therefore the nonlinear thermomechanical model for the simulation of the electron beam melting process can be solved more efficiently.…”

Section: Nonlinear Thermoelastic Modelmentioning

confidence: 99%

Thermomechanical Simulation of the Electron Beam Melting Process for TiAl6V4

Riedlbauer

Mergheim

Steinmann

2014

Proc Appl Math and Mech

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In the present contribution a nonlinear thermomechanical finite element model with temperature dependent material parameters is used to simulate the electron beam melting process for TiAl6V4. The beam is modeled as a moving heat source and the isentropic split solution scheme is applied. The temperature and stress distribution during the process were simulated and showed sound results from a qualitative point of view.

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Thermomechanical finite element simulations of selective electron beam melting processes: performance considerations

Cited by 44 publications

References 22 publications

Understanding the effect of laser scan strategy on residual stress in selective laser melting through thermo-mechanical simulation

Understanding the effect of laser scan strategy on residual stress in selective laser melting through thermo-mechanical simulation

A Fat boundary-type method for localized nonhomogeneous material problems

Thermomechanical Simulation of the Electron Beam Melting Process for TiAl6V4

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