Physics-Based Modeling and Predictive Simulation of Powder Bed Fusion Additive Manufacturing Across Length Scales
Christoph Meier, Sebastian L. Fuchs, Nils Much, Jonas Nitzler, Ryan W. Penny, Patrick M. Praegla, Sebastian D. Pröll, Yushen Sun, Reimar Weissbach, Magdalena Sc… 展开作者
Christoph Meier, Sebastian L. Fuchs, Nils Much, Jonas Nitzler, Ryan W. Penny, Patrick M. Praegla, Sebastian D. Pröll, Yushen Sun, Reimar Weissbach, Magdalena Schreter, Neil E. Hodge, A. John Hart, Wolfgang A. Wall
Powder bed fusion additive manufacturing (PBFAM) of metals has the potential to enable new paradigms of product design, manufacturing and supply chains while accelerating the realization of new technologies in the medical, aerospace, and other industries. Currently, wider adoption of PBFAM is held back by difficulty in part qualification, high production costs and low production rates, as extensive process tuning, post-processing, and inspection are required before a final part can be produced and deployed. Physics-based modeling and predictive simulation of PBFAM offers the potential to advance fundamental understanding of physical mechanisms that initiate process instabilities and cause defects. In turn, these insights can help link process and feedstock parameters with resulting part and material properties, thereby predicting optimal processing conditions and inspiring the development of improved processing hardware, strategies and materials. This work presents recent developments of our research team in the modeling of metal PBFAM processes spanning length scales, namely mesoscale powder modeling, mesoscale melt pool modeling, macroscale thermo-solid-mechanical modeling and microstructure modeling. Ongoing work in experimental validation of these models is also summarized. In conclusion, we discuss the interplay of these individual submodels within an integrated overall modeling approach, along with future research directions.
Many additive manufacturing (AM) technologies rely on powder feedstock, which is fused to form the final part either by melting or by chemical binding with subsequent sintering. In both cases, process stability and resulting part quality depend on dynamic interactions between powder particles and a fluid phase, i.e., molten metal or liquid binder. The present work proposes a versatile computational modeling framework for simulating such coupled microfluid-powder dynamics problems involving thermo-capillary flow and reversible phase transitions. In particular, a liquid and a gas phase are inter…
A Matlab-based computational procedure is proposed to fill a given volume with spheres whose radii are randomly picked from any specified probability distribution supported by \verb|Matlab|. The general program sequence and examples of filling a unit cube, a parallelepiped, and a concave domain between two hemispherical surfaces, with spheres whose radii are drawn from the Weibull and Gamma distributions, are presented. A sample application to the numerical modeling of bond formation between particles heated by a laser beam in powder bed 3D printing process is considered.
Limited process control can cause metallurgical defect formation and inhomogeneous relative density in laser powder bed fusion manufactured parts. In this study, cylindrical 15-5 PH stainless steel specimens are investigated by computer tomography; it shows an edge enhanced relative density profile. Additionally, the on axis monitoring signal, obtained from recording the thermal radiation of the melt pool, is considered. Analyzing data for the full duration of the building process results in a statistically increased melt pool signature close to the edge corresponding to the density profile. E…
Accurate prediction of melt pool shapes in laser powder bed fusion by the non-linear temperature equation including phase changes - isotropic versus anisotropic conductivity
在这方面的贡献，我们验证的物理模型的基础上瞬态温度方程（包括潜热）w.r.t. AMB 2018 -02是在美国国家标准与技术研究所建立的增材制造基准系列中提供的实验装置。我们的目标是预测以下感兴趣的量：宽度，深度和长度的熔池的数值模拟和报告也可获得的数值结果的冷却速率。我们首先假设激光器的双椭球形，并证明了一个良好的校准，纯热模型的基础上各向同性的热导率是能够预测所有感兴趣的数量，从实验测量值的最大偏差为7.3%。然而，有趣的是观察到，如果我们在模型中直接引入测量的激光轮廓（而不是双椭球形状），则所研究的模型返回与实验值的19.3%的偏差。这促使通过引入各向异性传导率来更新模型，该各向异性传导率旨在成为熔池内热材料对流的简化模型。这种各向异性模型能够预测上述所有感兴趣的量，与实验值的最大偏差为6.5%。我们注意到，虽然更具有预测性，但各向异性模型仅引起计算复杂性的边际增加。
From powder to part: influence of virgin and recovered Inconel 625 powders on the DED-LP processability, microstructure and mechanical properties
Univ. Bordeaux, ESTIA Institute of Technology（波尔多大学，ESTIA理工学院）；Arts et Métiers Institute of Technology, CNRS, Bordeaux INP, I2M, UMR 5295（巴黎国立高等工艺学院，法国国家科学研究中心，波尔多国立理工学院，I2M实验室）
The elasto-plastic material behavior, material strength and failure modes of metals fabricated by additive manufacturing technologies are significantly determined by the underlying process-specific microstructure evolution. In this work a novel physics-based and data-supported phenomenological microstructure model for Ti-6Al-4V is proposed that is suitable for the part-scale simulation of selective laser melting processes. The model predicts spatially homogenized phase fractions of the most relevant microstructural species, namely the stable $β$-phase, the stable $α_{\text{s}}$-phase as well a…
Wright State University（莱特州立大学）；Colorado School of Mines（科罗拉多矿业大学）；The George Washington University（乔治·华盛顿大学）；Open Additive, LLC（Open Additive 有限责任公司）
An additive manufacturing (AM) process, like laser powder bed fusion, allows for the fabrication of objects by spreading and melting powder in layers until a freeform part shape is created. In order to improve the properties of the material involved in the AM process, it is important to predict the material characterization property as a function of the processing conditions. In thermoelectric materials, the power factor is a measure of how efficiently the material can convert heat to electricity. While earlier works have predicted the material characterization properties of different thermoel…
Additive manufacturing is a free-form manufacturing technique in which parts are built in a layer-by-layer manner. Laser powder bed fusion is one of the popular techniques used to fabricate metal parts. However, it induces residual stress and distortion during fabrication that adversely affects the mechanical properties and dimensional accuracy of the manufactured parts. Therefore, predicting and avoiding the residual stress and distortion are critical issues. In this study, we propose a topology optimization method that accounts for the distortion. First, we propose a computationally inexpens…
A support structure is required to successfully create structural parts in the powder bed fusion process for additive manufacturing. In this study, we present the topology optimization of a support structure that improves the heat dissipation in the building process. First, we construct a numerical method that obtains the temperature field in the building process, represented by the transient heat conduction phenomenon with the volume heat flux. Next, we formulate an optimization problem for maximizing heat dissipation and develop an optimization algorithm that incorporates a level-set-based t…
Deterministic computational modeling of laser powder bed fusion (LPBF) process fails to capture irregularities and roughness of the scan track, unless expensive powder-scale analysis is used. In this work we developed a stochastic computational modeling framework based on Markov Chain Monte Carlo (MCMC) capable of capturing the irregularities of LPBF scan. The model is calibrated against AFRL single track scan data using a specially designed tensor decomposition method, i.e., Higher-Order Proper Generalized Decomposition (HOPGD) that relies on non-intrusive data learning and construction of re…
This article proposes a coupled thermomechanical finite element model tailored to the macroscale simulation of metal additive manufacturing processes such as selective laser melting. A first focus lies on the derivation of a consistent constitutive law on basis of a Voigt-type spatial homogenization procedure across the relevant phases, powder, melt and solid. The proposed constitutive law accounts for the irreversibility of phase change and consistently represents thermally induced residual stresses. In particular, the incorporation of a reference strain term, formulated in rate form, allows …
Thermal multi-phase flow simulations are indispensable to understanding the multi-scale and multi-physics phenomena in metal additive manufacturing (AM) processes, yet accurate and robust predictions remain challenging. This book chapter summarizes the recent method development at UIUC for simulating thermal multiphase flows in laser powder bed fusion (LPBF) and directed energy deposition (DED) processes. Two main method developments are discussed. The first is a mixed interface-capturing/interface-tracking computational framework aiming to explicitly treat the gas-metal interface without mesh…
