A computational reduction model for appraising structural effects in selective laser melting manufacturing

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

doi:10.1080/17452759.2013.868005

Cited by 77 publications

(39 citation statements)

References 13 publications

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“…The thermal model remains geometrically fixed during the whole thermal analysis whereas the mechanical model distorts as the calculations progress in time. Such an approach is permissible in the case of a relatively small structure deformation [58]. The successive computations are repeated as many times as melt beads need to be deposited to create the workpiece.…”

Section: Macromodelingmentioning

confidence: 99%

See 1 more Smart Citation

Metal additive-manufacturing process and residual stress modeling

Megahed

Mindt

N’Dri

et al. 2016

Integr Mater Manuf Innov

223

113

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Additive manufacturing (AM), widely known as 3D printing, is a direct digital manufacturing process, where a component can be produced layer by layer from 3D digital data with no or minimal use of machining, molding, or casting. AM has developed rapidly in the last 10 years and has demonstrated significant potential in cost reduction of performance-critical components. This can be realized through improved design freedom, reduced material waste, and reduced post processing steps. Modeling AM processes not only provides important insight in competing physical phenomena that lead to final material properties and product quality but also provides the means to exploit the design space towards functional products and materials. The length-and timescales required to model AM processes and to predict the final workpiece characteristics are very challenging. Models must span length scales resolving powder particle diameters, the build chamber dimensions, and several hundreds or thousands of meters of heat source trajectories. Depending on the scan speed, the heat source interaction time with feedstock can be as short as a few microseconds, whereas the build time can span several hours or days depending on the size of the workpiece and the AM process used. Models also have to deal with multiple physical aspects such as heat transfer and phase changes as well as the evolution of the material properties and residual stresses throughout the build time. The modeling task is therefore a multi-scale, multi-physics endeavor calling for a complex interaction of multiple algorithms. This paper discusses models required to span the scope of AM processes with a particular focus towards predicting as-built material characteristics and residual stresses of the final build. Verification and validation examples are presented, the over-spanning goal is to provide an overview of currently available modeling tools and how they can contribute to maturing additive manufacturing.

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Section: Macromodelingmentioning

confidence: 99%

“…They are computed separately, presenting a one-way coupling of the thermo-mechanical computation. The transient temperature field is stored at every time step and is then applied as a thermal load in the quasi-static thermo-mechanical analysis [56][57][58]. As shown in Fig.…”

Section: Macromodelingmentioning

confidence: 99%

Metal additive-manufacturing process and residual stress modeling

Megahed

Mindt

N’Dri

et al. 2016

Integr Mater Manuf Innov

223

113

View full text Add to dashboard Cite

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“…Some studies that discuss the pros and cons of support structures to prevent damage in SLM/DMLS well were those performed by Hussein et al [21,22], Jhabvala et al [28], Matsumoto et al [18], Thomas and Bibb [29,30], Wang et al [31], Kruth et al [32] and Papadakis et al [33]. Data from several studies by Hussein et al [22], Kruth et al [32], Vora et al [34] and Patterson et al [35,36] suggested that the use of rigid support structures during SLM/DMLS for overhanging features may actually cause the residual stresses to be worse than if the overhang had no solid support during printing.…”

Section: Survey Of Previous Workmentioning

confidence: 99%

“…Another research group based primarily in Germany, Papadakis et al [33], proposed a model reduction in order to simplify the creation and running of good finite element models of the thermal and mechanical effects in large parts made by SLM. The study shows that for large parts, the finite element model can be simplified without a significant loss of accuracy and usability.…”

Section: General Slm/dmls Process Modelsmentioning

confidence: 99%

Overhanging Features and the SLM/DMLS Residual Stresses Problem: Review and Future Research Need

2017

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Abstract:A useful and increasingly common additive manufacturing (AM) process is the selective laser melting (SLM) or direct metal laser sintering (DMLS) process. SLM/DMLS can produce full-density metal parts from difficult materials, but it tends to suffer from severe residual stresses introduced during processing. This limits the usefulness and applicability of the process, particularly in the fabrication of parts with delicate overhanging and protruding features. The purpose of this study was to examine the current insight and progress made toward understanding and eliminating the problem in overhanging and protruding structures. To accomplish this, a survey of the literature was undertaken, focusing on process modeling (general, heat transfer, stress and distortion and material models), direct process control (input and environmental control, hardware-in-the-loop monitoring, parameter optimization and post-processing), experiment development (methods for evaluation, optical and mechanical process monitoring, imaging and design-of-experiments), support structure optimization and overhang feature design; approximately 143 published works were examined. The major findings of this study were that a small minority of the literature on SLM/DMLS deals explicitly with the overhanging stress problem, but some fundamental work has been done on the problem. Implications, needs and potential future research directions are discussed in-depth in light of the present review.

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“…However, residual stress is a serious issue in SLM [5]. As a result, researchers have worked to develop solutions to this problem, such as process modeling and simulation [6], process control and post-processing methods [7,8], design and analysis of overhanging structures [9], and so on. However, the current research does not provide a standard solution as different cases have different solutions.…”

Section: Introductionmentioning

confidence: 99%

Discrete Optimization of Internal Part Structure via SLM Unit Structure-Performance Database

Tang

Zhang

Liang

et al. 2018

Metals

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Abstract:The structural optimization of the internal structure of parts based on three-dimensional (3D) printing has been recognized as being important in the field of mechanical design. The purpose of this paper is to present a creation of a unit structure-performance database based on the selective laser melting (SLM), which contains various structural units with different functions and records their structure and performance characteristics so that we can optimize the internal structure of parts directly, according to the database. The method of creating the unit structure-performance database was introduced in this paper and several structural units of the unit structure-performance database were introduced. The bow structure unit was used to show how to create the structure-performance database of the unit as an example. Some samples of the bow structure unit were designed and manufactured by SLM. These samples were tested in the WDW-100 compression testing machine to obtain their performance characteristics. After this, the paper collected all data regarding unit structure parameters, weight, performance characteristics, and other data; and, established a complete set of data from the bow structure unit for the unit structure-performance database. Furthermore, an aircraft part was reconstructed conveniently to be more lightweight according to the unit structure-performance database. Its weight was reduced by 36.8% when compared with the original structure, while the strength far exceeded the requirements.

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A computational reduction model for appraising structural effects in selective laser melting manufacturing

Cited by 77 publications

References 13 publications

Metal additive-manufacturing process and residual stress modeling

Metal additive-manufacturing process and residual stress modeling

Overhanging Features and the SLM/DMLS Residual Stresses Problem: Review and Future Research Need

Discrete Optimization of Internal Part Structure via SLM Unit Structure-Performance Database

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