Part-scale thermal simulation of laser powder bed fusion using graph theory: Effect of thermal history on porosity, microstructure evolution, and recoater crash

Yavari, Reza; Smoqi, Ziyad; Riensche, Alex; Bevans, Ben; Kobir, Md Humaun; Mendoza, Heimdall; Song, Hyeyun; Cole, Kevin D.; Rao, Prahalada

doi:10.1016/j.matdes.2021.109685

Cited by 53 publications

(10 citation statements)

References 73 publications

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“…Figure 15 shows four photographs of the produced parts. After successfully manufacturing the designed parts, students are tasked with visually inspecting the surface quality of the parts on the build plate and reporting any F I G U R E 15 (a) Renishaw AM 400 at CAVS MSU [45], (b) an illustrative schematic of the LPBF process [63], manufactured specimens from Afify et al [2] such as (c) front view, (d) back view, (e) side view (Reproduced from Afify et al [2], with permission from Springer Nature). damaged regions that may arise due to uncontrolled residual stresses.…”

Section: Lpbf Production Phase and Postprocessingmentioning

confidence: 99%

See 1 more Smart Citation

A hybrid CAD/CAE/CAM project‐based laboratory framework integrating topology optimization and laser powder bed fusion for engineering education

Afify,

Moubachir,

Guennoun

et al. 2024

Comp Applic In Engineering

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In the era of Industry 4.0, laser‐based additive manufacturing (LBAM) has gained substantial momentum in the production of complex lightweight structures in several domains such as aerospace, civil, and biomedical engineering. The increasing demand for consistent and precise manufacturing processes has urged the manufacturing industry to consider the coupling of topology optimization (TO) and laser powder bed fusion (LPBF) in the design of sophisticatedly novel topologies that are unattainable through traditional processes. Notably, this union has demonstrated a highly efficient and productive capability toward the manufacturing industry. In line with this accelerated pace, engineering programs within universities exert significant effort to revise and update their engineering curriculum design to incorporate emerging manufacturing technologies providing students with skills that are aligned with the actual industrial context. In this article, a computer‐aided design (CAD)/computer‐aided engineering (CAE)/computer‐aided manufacturing (CAM) project‐based laboratory framework is proposed combining TO and LPBF exploiting a simulation‐based environment integrating CAD, CAE, and CAM. The structure of the proposed CAD/CAE/CAM design methodology is revisited to discern the added value of the newly developed framework and its particularity in assisting aerospace engineering students to meet industrial expectations. A new CAD/CAE/CAM project‐based laboratory framework has been developed integrating TO and LPBF using advanced engineering tools within the aerospace engineering education.

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Section: Lpbf Production Phase and Postprocessingmentioning

confidence: 99%

“…(a) Renishaw AM 400 at CAVS MSU [45], (b) an illustrative schematic of the LPBF process [63], manufactured specimens from Afify et al [2] such as (c) front view, (d) back view, (e) side view (Reproduced from Afify et al [2], with permission from Springer Nature).…”

Section: Development Of a Cad/cae/cam Project‐based Laboratory Frameworkmentioning

confidence: 99%

A hybrid CAD/CAE/CAM project‐based laboratory framework integrating topology optimization and laser powder bed fusion for engineering education

Afify,

Moubachir,

Guennoun

et al. 2024

Comp Applic In Engineering

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“…Nonuniform geometries can result in varying heat flow through the part, thus leading to different thermal properties affecting the microstructure and part quality. Therefore, understanding the correlation between thermal history and material properties are the bases of recent investigations [15][16][17][18][19]. Both Williams et al [15] and Mohr et al [16] studied the effects of varying inter-layer cooling times during PBF-LB.…”

Section: Introductionmentioning

confidence: 99%

“…For a prediction of part defects dependent on geometrical features, Paulson et al [18] established machine-learning models that correlate thermal histories of single-track deposits to subsurface porosity formation. Similarly, Yavari et al [19] introduced a graph theory approach to predict thermal history trends that lead to flaw formation. A correlation between part geometry and thermal history was found, thus influencing the occurrence of build failures, type and severity of porosity as well as morphology of the microstructure.…”

Section: Introductionmentioning

confidence: 99%

Geometrical Influence on Material Properties for Ti6Al4V Parts in Powder Bed Fusion

Nahr

Rasch

Burkhardt

et al. 2023

JMMP

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One major advantage of additive manufacturing is the high freedom of design, which supports the fabrication of complex structures. However, geometrical features such as combined massive volumes and cellular structures in such parts can lead to an uneven heat distribution during processing, resulting in different material properties throughout the part. In this study, we demonstrate these effects, using a complex structure consisting of three conic shapes with narrow cylinders in between hindering heat flux. We manufacture the parts via powder bed fusion of Ti6Al4V by applying a laser beam (PBF-LB/M) as well as an electron beam (PBF-EB). We investigate the impact of the different thermal regimes on the part density, microstructure and mechanical properties aided by finite element simulations as well as by thermography and X-ray computed tomography measurements. Both simulations and thermography show an increase in inter-layer temperature with increasing part radius, subsequently leading to heat accumulation along the build direction. While the geometry and thermal history have a minor influence on the relative density of the parts, the microstructure is greatly affected by the thermal history in PBF-LB/M. The acicular martensitic structure in the narrow parts is decomposed into a mix of tempered lath-like martensite and an ultrafine α + β microstructure with increasing part radius. The EBM part exhibits a lamellar α + β microstructure for both the cylindric and conic structures. The different microstructures directly influence the hardness of the parts. For the PBF-LB part, the hardness ranges between 400 HV0.5 in the narrow sections and a maximum hardness of 450 HV0.5 in the broader sections, while the PBF-EB part exhibits hardness values between 280 and 380 HV0.5.

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“…This research addresses the foregoing challenge by devising a mesh-free graph theory-based computational thermal modeling approach to predict the temperature distribution in DED parts. The graph theory approach has previously been published in the context of the laser powder bed fusion (LPBF) process (Yavari et al , 2019; Cole et al , 2020; Yavari et al , 2020; Gaikwad et al , 2020; Yavari et al , 2021a, 2021b, 2021c). The approach is verified to be five to ten times faster than FE modeling, enabling the prediction of thermal history using desktop computing in the context of the LPBF process. This paper develops, applies and validates the graph theory approach in the context of the DED process.…”

Section: Introductionmentioning

confidence: 99%

Thermal modeling of directed energy deposition additive manufacturing using graph theory

Riensche

Severson

Yavari

et al. 2022

RPJ

Self Cite

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Purpose The purpose of this paper is to develop, apply and validate a mesh-free graph theory–based approach for rapid thermal modeling of the directed energy deposition (DED) additive manufacturing (AM) process. Design/methodology/approach In this study, the authors develop a novel mesh-free graph theory–based approach to predict the thermal history of the DED process. Subsequently, the authors validated the graph theory predicted temperature trends using experimental temperature data for DED of titanium alloy parts (Ti-6Al-4V). Temperature trends were tracked by embedding thermocouples in the substrate. The DED process was simulated using the graph theory approach, and the thermal history predictions were validated based on the data from the thermocouples. Findings The temperature trends predicted by the graph theory approach have mean absolute percentage error of approximately 11% and root mean square error of 23°C when compared to the experimental data. Moreover, the graph theory simulation was obtained within 4 min using desktop computing resources, which is less than the build time of 25 min. By comparison, a finite element–based model required 136 min to converge to similar level of error. Research limitations/implications This study uses data from fixed thermocouples when printing thin-wall DED parts. In the future, the authors will incorporate infrared thermal camera data from large parts. Practical implications The DED process is particularly valuable for near-net shape manufacturing, repair and remanufacturing applications. However, DED parts are often afflicted with flaws, such as cracking and distortion. In DED, flaw formation is largely governed by the intensity and spatial distribution of heat in the part during the process, often referred to as the thermal history. Accordingly, fast and accurate thermal models to predict the thermal history are necessary to understand and preclude flaw formation. Originality/value This paper presents a new mesh-free computational thermal modeling approach based on graph theory (network science) and applies it to DED. The approach eschews the tedious and computationally demanding meshing aspect of finite element modeling and allows rapid simulation of the thermal history in additive manufacturing. Although the graph theory has been applied to thermal modeling of laser powder bed fusion (LPBF), there are distinct phenomenological differences between DED and LPBF that necessitate substantial modifications to the graph theory approach.

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Part-scale thermal simulation of laser powder bed fusion using graph theory: Effect of thermal history on porosity, microstructure evolution, and recoater crash

Cited by 53 publications

References 73 publications

A hybrid CAD/CAE/CAM project‐based laboratory framework integrating topology optimization and laser powder bed fusion for engineering education

A hybrid CAD/CAE/CAM project‐based laboratory framework integrating topology optimization and laser powder bed fusion for engineering education

Geometrical Influence on Material Properties for Ti6Al4V Parts in Powder Bed Fusion

Thermal modeling of directed energy deposition additive manufacturing using graph theory

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