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Physics guided heat source for quantitative prediction of IN718 laser additive manufacturing processes

npj Computational Materials 2024年第1期10卷 2854-2867页

作者： Abdullah Al Amin Yangfan Li Ye Lu Xiaoyu Xie Zhengtao Gan Satyajit Mojumder Gregory J.Wagner Wing Kam Liu Department of Mechanical Engineering Northwestern UniversityEvanston 60208 ILUSA Department of Mechanical and Aerospace Engineering University of DaytonDaytonOHUSA Department of Mechanical Engineering University of MarylandBaltimore CountyBaltimoreMD 21250USA Department of Aerospace&Mechanical Engineering University of Texas at El PasoEl PasoTXUSA Theoritical and Applied Mechanics Program Northwestern UniversityEvanston 60208 ILUSA

Challenge 3 of the 2022 NIST additive manufacturing benchmark(AM Bench)experiments asked modelers to submit predictions for solid cooling rate,liquid cooling rate,time above melt,and melt pool geometry for single and multiple track laser powder bed fusion process using moving *** in-house developed Additive Manufacturing Computational Fluid Dynamics code(AM-CFD)combined with a cylindrical heat source is implemented to accurately predict these *** heat source calibration is proposed relating volumetric energy density(ψ)based on experiments available in the *** parameters of the heat source of the computational model are initially calibrated based on a Higher Order Proper Generalized Decomposition-(HOPGD)based surrogate *** prediction using the calibrated heat source agrees quantitatively with NIST measurements for different process conditions(laser spot diameter,laser power,and scan speed).A scaling law based on keyhole formation is also utilized in calibrating the parameters of the cylindrical heat source and predicting the challenge *** addition,an improvement on the heat source model is proposed to relate the Volumetric Energy Density(VED_(σ))to the melt pool aspect *** model shows further improvement in the prediction of the experimental measurements for the melt pool,including cases at higher VED_(σ).Overall,it is concluded that the appropriate selection of laser heat source parameterization scheme along with the heat source model is crucial in the accurate prediction of melt pool geometry and thermal measurements while bypassing the expensive computational simulations that consider increased physics equations.

关键词： prediction source additive

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Impact of Cryopreservation on Elastomuscular Artery mechanics

SSRN

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SSRN 2024年

作者： Kostelnik, Colton J. Crouse, Kiersten J. Goldsmith, Jackson D. Eberth, John F. Aerospace Engineering and Engineering Mechanics The University of Texas at Austin AustinTX United States Biomedical Engineering Program University of South Carolina ColumbiaSC United States Mechanical Engineering Department University of South Carolina ColumbiaSC United States Biomedical Engineering Science and Health Systems Drexel University PhiladelphiaPA United States

Low temperatures slow or halt undesired biological and chemical processes, protecting cells, tissues, and organs during storage. Cryopreservation techniques, including controlled media exchange and regulated freezing conditions, aim to mitigate the physical consequences of freezing. Dimethyl sulfoxide (DMSO), for example, is a penetrating cryoprotecting agent (CPA) that minimizes ice crystal growth by replacing intracellular water, while polyvinyl alcohol (PVA) is a nonpenetrating CPA that prevents recrystallization during thawing. Since proteins and ground substance dominate the passive properties of soft biological tissues, we studied how different freezing rates, storage temperatures, storage durations, and presence of cryoprotecting agents (5% [v/v] DMSO + 1 mg/mL PVA) impact the histomechanical properties of the internal thoracic artery (ITA), a clinically relevant blood vessel with both elastic and muscular characteristics. Remarkably, biaxial mechanical analyses failed to reveal significant differences among the ten groups tested, suggesting that mechanical properties are virtually independent of cryopreservation technique. Scanning electron microscopy revealed minor CPA-independent delamination in rapidly frozen samples, while cryoprotected ITAs had better post-thaw viability than their unprotected counterparts using methyl thiazole-tetrazolium (MTT) metabolic assays, especially when frozen at a controlled rate. These results can be used to inform ongoing and future studies in vascular engineering and analysis. © 2024, The Authors. All rights reserved.

关键词： Dimethyl sulfoxide

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Design, Fabrication, and Testing of Stiffened Composite Panels with Acoustically Tailored Stiffeners 79

Design, Fabrication, and Testing of Stiffened Composite Pane...

引用

79th Vertical Flight Society Annual Forum and Technology Display, FORUM 2023

作者： Brown, Avery Moorhouse, Anna M. Bakis, Charles E. Smith, Edward C. Beck, Ben S. Shepherd, Micah R. Engineering Science and Mechanics Dept. Pennsylvania State Univ. University ParkPA United States Graduate Program in Acoustics Pennsylvania State Univ. University ParkPA United States Aerospace Engineering Dept. Pennsylvania State Univ. University ParkPA United States Engineering Acoustics Dept. Applied Research Laboratory State CollegePA United States Physics and Astronomy Dept. Brigham Young Univ. ProvoUT United States

ISBN: (纸本)9781713874799

Carbon fiber reinforced epoxy composites are being increasingly used for load bearing structural elements in large transport rotorcraft. However, due to the increased stiffness-to-density ratio of composites, problems associated with vibration and interior noise can be exacerbated by the use of composites in airframes. The current investigation explores the potential of optimized composite meta-structures to reduce vibration and interior noise in rotorcraft. The approach involves designing a taper into the thickness of blade stiffeners which, when combined with a limited amount of absorbing material in the thinned region, creates what is known as an "acoustic black hole" (ABH) in the stiffener. It is hypothesized that optimally designed ABH stiffeners can reduce broadband vibrations in stiffened panels. An optimization routine has been developed to determine the tradeoffs between vibration, mass, and buckling load due to compression parallel to the stiffeners. The tradeoffs are visualized using a 3-D Pareto front that helps the designer decide on the optimal design. Carbon/epoxy panels were made using vacuum-bag-oven processing with out-of-autoclave prepreg and verified to be of good quality. Panel vibration, buckling onset, and post-buckling load-deflection behavior were simulated using finite elements and measured using model testing and compression testing. Based on preliminary results, ABH-tapered stiffened panels have the ability to reduce radiated noise without a significant penalty in the mass and compressive load-bearing capability. Copyright © 2023 by the Vertical Flight Society. All rights reserved.

关键词： Optimal systems

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Temporal refraction and reflection in modulated mechanical metabeams: theory and physical observation

arXiv

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arXiv 2025年

作者： Wang, Shaoyun Shao, Nan Chen, Hui Chen, Jiaji Qian, Honghua Wu, Qian Duan, Huiling Alù, Andrea Huang, Guoliang Department of Mechanical and Aerospace Engineering University of Missouri ColumbiaMO65211 United States Center for Mechanics Plus Under Extreme Environments School of Mechanical Engineering and Mechanics Ningbo University Ningbo315211 China Photonics Initiative Advanced Science Research Center City University of New York New YorkNY United States Physics Program Graduate Center City University of New York New YorkNY United States Department of Mechanics and Engineering Science College of Engineering Peking University Beijing100871 China

Wave reflection and refraction at a time interface follow different conservation laws compared to conventional scattering at a spatial interface. This study presents the experimental demonstration of refraction and reflection of flexural waves across a temporal boundary in a continuum-based mechanical metabeam, and unveils opportunities that emerge by tailoring temporal scattering phenomena for phononic applications. We observe these phenomena in an elastic beam attached to an array of piezoelectric patches that can vary in time the effective elastic properties of the beam. Frequency conversion and phase conjugation are observed upon a single temporal interface. These results are consistent with the temporal Snell’s law and Fresnel equations for temporal interfaces. Further, we illustrate the manipulation of amplitude and frequency spectra of flexural wave temporal refraction and reflection through multi-stepped temporal interfaces. Finally, by implementing a smooth time variation of wave impedance, we numerically and experimentally demonstrate the capabilities of the temporal metabeam to realize waveform morphing and information coding. Our findings lay the foundation for developing time-mechanical metamaterials and time-phononic crystals, offering new avenues for advanced phonon manipulation in both wave amplitude and frequency. © 2025, CC BY.

关键词： Phonons

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A Novel Indirect Scheme for Optimal Lunar Soft Landing at a Target Site

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Journal of The Institution of Engineers (India): Series C 2021年第6期102卷 1379-1393页

作者： Remesh, N. Ramanan, R.V. Lalithambika, V.R. Flight Mechanics Group ISRO- Vikram Sarabhai Space Centre Trivandrum India Department of Aerospace Engineering Indian Institute of Space Science and Technology Trivandrum India Directorate of Human Space Flight Program ISRO Head Quarters Bangalore India

The problem of precise and soft lunar landing in a pre-specified target location is solved using a numerical scheme based on indirect approach. In indirect approach, the problem is transformed into a two-point boundary value problem using Pontryagin’s principle and solved. The challenge in the indirect approach lies in finding suitable initial co-states with no prior knowledge available about them. In the proposed numerical scheme, the differential transformation (DT) technique is employed to determine the unknown initial co-states using the information on the target site and the flight time. The flight time, the only unknown, is handled by differential evolution, an optimization technique. The novel computational scheme combines differential transformation and differential evolution techniques and uses differential transformation in multi-steps, to ensure the precise landing at the target site. The guidelines that help fixing the bounds for the flight time are provided. The proposed scheme is uniformly valid for various performance measures such as minimum fuel, minimum control and minimum time. Also, it is capable of introducing coasting during descent while maximizing the landing mass. © 2021, The Institution of Engineers (India).

关键词： Landing

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Geometry of transit orbits in the periodically-perturbed restricted three-body problem

arXiv

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arXiv 2022年

作者： Fitzgerald, Joshua Ross, Shane D. Engineering Mechanics Program Virginia Tech Blacksburg VA24061 United States Aerospace and Ocean Engineering Virginia Tech Blacksburg VA24061 United States

In the circular restricted three-body problem, low energy transit orbits are revealed by linearizing the governing differential equations about the collinear Lagrange points. This procedure fails when time-periodic perturbations are considered, such as perturbation due to the sun (i.e., the bicircular problem) or orbital eccentricity of the primaries. For the case of a time-periodic perturbation, the Lagrange point is replaced by a periodic orbit, equivalently viewed as a hyperbolic-elliptic fixed point of a symplectic map (the stroboscopic Poincaré map). Transit and non-transit orbits can be identified in the discrete map about the fixed point, in analogy with the geometric construction of Conley and McGehee about the index-1 saddle equilibrium point in the continuous dynamical system. Furthermore, though the continuous time system does not conserve the Hamiltonian energy (which is time-varying), the linearized map locally conserves a time-independent effective Hamiltonian function. We demonstrate that the phase space geometry of transit and non-transit orbits is preserved in going from the unperturbed to a periodically-perturbed situation, which carries over to the full nonlinear *** Codes 70F07 (Primary) Copyright © 2022, The Authors. All rights reserved.

关键词： Continuous time systems

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Uncertainty Quantification and Propagation for Multiscale Materials Systems with Agglomeration and Structural Anomalies

SSRN

引用

SSRN 2024年

作者： Comlek, Yigitcan Mojumder, Satyajit van Beek, Anton Prabhune, Prajakta Ciampaglia, Alberto Apley, Daniel W. Brinson, L. Catherine Liu, Wing Kam Chen, Wei Department of Mechanical Engineering Northwestern University Evanston United States Theoretical and Applied Mechanics Program Northwestern University Evanston United States School of Mechanical and Materials Engineering University College Dublin Dublin Ireland Thomas Lord Department of Mechanical Engineering and Materials Science Duke University Durham United States Department of Mechanical and Aerospace Engineering Politecnico di Torino Turin Italy Department of Industrial Engineering and Management Sciences Northwestern University Evanston United States

Advancements in manufacturing technologies have enabled material system design optimization at multiple length scales. However, the microstructural anomalies and uncertainties present at each scale have not been considered comprehensively enough for systems to be robust to manufacturing variations. Consequently, considering anomalies at various length scales of the material’s structure and understanding their effects on a part’s response are crucial for designing engineered parts that are robust to various sources of uncertainty. In this work, an efficient bottom-up hierarchical uncertainty quantification and propagation framework bridging multiple scales to establish a design allowable range for the material system at the part-scale is presented. We demonstrate our framework on an additively manufactured polymer nanocomposite material system that is subject to anomalies at different length scales that impact the material properties. Specifically, agglomeration defects formed due to attractive forces between nanoparticles at the microscale and structural variabilities caused by the voids resulting from different processing conditions at the mesoscale are considered. The introduced hierarchical sampling framework combines (i) an innovative microstructure image characterization and reconstruction, (ii) a mechanistic reduced-order model that enables fast property predictions for high-dimensional microstructural design spaces, and (iii) efficient uncertainty quantification and propagation through Copula-based sampling across multiple length scales to reduce the sampling budget by 95%. Through validation of our method, we demonstrate the importance of considering the effects of process-induced microstructure features on the performance of a part. © 2024, The Authors. All rights reserved.

关键词： Microstructure

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Creating Continuously Graded Microstructures with Electric Fields via Locally Altering Grain Boundary Complexions

arXiv

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arXiv 2023年

作者： Yan, Qizhang Hu, Chongze Luo, Jian Department of Nano and Chemical Engineering University of California San Diego La Jolla CA92093 United States Program in Materials Science and Engineering University of California San Diego La Jolla CA92093 United States Department of Aerospace Engineering and Mechanics University of Alabama TuscaloosaAL35487 United States

Tailoring microstructures represents a daunting goal in materials science. Here, an innovative proposition is to utilize grain boundary (GB) complexions (a.k.a. interfacial phases) to manipulate microstructural evolution, which is challenging to control via only temperature and doping. Herein, we use ZnO as a model system to tailor microstructures using applied electric fields as a new knob to control GB structures locally via field-driven stoichiometry (defects) polarization. Specifically, continuously graded microstructures are created under applied electric fields. By employing aberration-corrected scanning transmission electron microscopy (AC STEM) in conjunction with density functional theory (DFT) and ab initio molecular dynamics (AIMD), we discover cation-deficient, oxygen-rich GBs near the anode with enhanced GB diffusivities. In addition, the field-driven redistribution of cation vacancies is deduced from a defect chemistry model, and subsequently verified by spatially resolved photoluminescence spectroscopy. This bulk stoichiometry polarization leads to preferential formation of cation-deficient (oxidized) GBs near the anode to gradually promote grain growth towards the anode. This mechanism can be utilized to create continuously graded microstructures without abnormal grain growth typically observed in prior studies. This study exemplifies a case of tailoring microstructural evolution via altering GB complexions locally with applied electric fields, and it enriches fundamental GB science. © 2023, CC BY.

关键词： Density functional theory

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INTERPOLATING NEURAL NETWORK: A NOVEL UNIFICATION OF MACHINE LEARNING AND INTERPOLATION THEORY

arXiv

引用

arXiv 2024年

作者： Park, Chanwook Guo, Jiachen Xie, Xiaoyu Qian, Dong Wagner, Gregory J. Saha, Sourav Zhang, Hantao Bessa, Miguel A. Chen, Wei Cao, Jian Liu, Wing Kam Department of Mechanical Engineering Northwestern University EvanstonIL60208 United States Theoretical and Applied Mechanics Program Northwestern University EvanstonIL60208 United States Department of Mechanical Engineering University of Texas at Dallas RichardsonTX75080 United States Department of Aerospace and Ocean Engineering Virginia Polytechnic Institute State University BlacksburgVA24060 United States School of Engineering Brown University ProvidenceRI United States

Artificial intelligence (AI) has revolutionized software development, shifting from task-specific codes (Software 1.0) to neural network-based approaches (Software 2.0). However, applying this transition in engineering software presents challenges, including low surrogate model accuracy, the curse of dimensionality in inverse design, and rising complexity in physical simulations. We introduce an interpolating neural network (INN), grounded in numerical methods, to realize engineering Software 2.0 by advancing data training, partial differential equation solving, and parameter calibration. INN offers orders of magnitude fewer trainable/solvable parameters for comparable model accuracy than traditional multi-layer perceptron (MLP) or physics-informed neural networks (PINN). Demonstrated in metal additive manufacturing, INN rapidly constructs an accurate surrogate model of Laser Powder Bed Fusion (L-PBF) heat transfer simulation, achieving sub-10-micrometer resolution for a 10 mm path in under 15 minutes on a single GPU. This makes a transformative step forward across all domains essential to engineering software. Copyright © 2024, The Authors. All rights reserved.

关键词： Multilayer neural networks

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Technology Roadmap for Flexible Sensors

引用

ACS NANO 2023年第6期17卷 5211-5295页

作者： Luo, Yifei Abidian, Mohammad Reza Ahn, Jong-Hyun Akinwande, Deji Andrews, Anne M. Antonietti, Markus Bao, Zhenan Berggren, Magnus Berkey, Christopher A. Bettinger, Christopher John Chen, Jun Chen, Peng Cheng, Wenlong Cheng, Xu Choi, Seon-Jin Chortos, Alex Dagdeviren, Canan Dauskardt, Reinhold H. Di, Chong-an Dickey, Michael D. Duan, Xiangfeng Facchetti, Antonio Fan, Zhiyong Fang, Yin Feng, Jianyou Feng, Xue Gao, Huajian Gao, Wei Gong, Xiwen Guo, Chuan Fei Guo, Xiaojun Hartel, Martin C. He, Zihan Ho, John S. Hu, Youfan Huang, Qiyao Huang, Yu Huo, Fengwei Hussain, Muhammad M. Javey, Ali Jeong, Unyong Jiang, Chen Jiang, Xingyu Kang, Jiheong Karnaushenko, Daniil Khademhosseini, Ali Kim, Dae-Hyeong Kim, Il-Doo Kireev, Dmitry Kong, Lingxuan Lee, Chengkuo Lee, Nae-Eung Lee, Pooi See Lee, Tae-Woo Li, Fengyu Li, Jinxing Liang, Cuiyuan Lim, Chwee Teck Lin, Yuanjing Lipomi, Darren J. Liu, Jia Liu, Kai Liu, Nan Liu, Ren Liu, Yuxin Liu, Yuxuan Liu, Zhiyuan Liu, Zhuangjian Loh, Xian Jun Lu, Nanshu Lv, Zhisheng Magdassi, Shlomo Malliaras, George G. Matsuhisa, Naoji Nathan, Arokia Niu, Simiao Pan, Jieming Pang, Changhyun Pei, Qibing Peng, Huisheng Qi, Dianpeng Ren, Huaying Rogers, John A. Rowe, Aaron Schmidt, Oliver G. Sekitani, Tsuyoshi Seo, Dae-Gyo Shen, Guozhen Sheng, Xing Shi, Qiongfeng Someya, Takao Song, Yanlin Stavrinidou, Eleni Su, Meng Sun, Xuemei Takei, Kuniharu Tao, Xiao-Ming Tee, Benjamin C. K. Thean, Aaron Voon-Yew Trung, Tran Quang Wan, Changjin Wang, Huiliang Wang, Joseph Wang, Ming Wang, Sihong Wang, Ting Wang, Zhong Lin Weiss, Paul S. Wen, Hanqi Xu, Sheng Xu, Tailin Yan, Hongping Yan, Xuzhou Yang, Hui Yang, Le Yang, Shuaijian Yin, Lan Yu, Cunjiang Yu, Guihua Yu, Jing Yu, Shu-Hong Yu, Xinge Zamburg, Evgeny Zhang, Haixia Zhang, Xiangyu Zhang, Xiaosheng Zhang, Xueji Zhang, Yihui Zhang, Yu Zhao, Siyuan Zhao, Xuanhe Zheng, Yuanjin Zheng, Yu-Qing Zheng, Zijian Zhou, Tao Zhu, Bowen Zhu, Ming Zhu, Rong Zhu, Yangzhi Zhu, Yong Zou, Guijin Chen, Xiaodong 08-03 Innovis Singapore 138634 Republic of Singapore Innovative Centre for Flexible Devices (iFLEX) School of Materials Science and Engineering Nanyang Technological University Singapore 639798 Singapore Department of Biomedical Engineering University of Houston Houston Texas 77024 United States School of Electrical and Electronic Engineering Yonsei University Seoul 03722 Republic of Korea Department of Electrical and Computer Engineering The University of Texas at Austin Austin Texas 78712 United States Microelectronics Research Center The University of Texas at Austin Austin Texas 78758 United States Department of Chemistry and Biochemistry California NanoSystems Institute and Department of Psychiatry and Biobehavioral Sciences Semel Institute for Neuroscience and Human Behavior and Hatos Center for Neuropharmacology University of California Los Angeles Los Angeles California 90095 United States Colloid Chemistry Department Max Planck Institute of Colloids and Interfaces 14476 Potsdam Germany Department of Chemical Engineering Stanford University Stanford California 94305 United States Laboratory of Organic Electronics Department of Science and Technology Campus Norrköping Linköping University 83 Linköping Sweden Wallenberg Initiative Materials Science for Sustainability (WISE) and Wallenberg Wood Science Center (WWSC) SE-100 44 Stockholm Sweden Department of Materials Science and Engineering Stanford University Stanford California 94301 United States Department of Biomedical Engineering and Department of Materials Science and Engineering Carnegie Mellon University Pittsburgh Pennsylvania 15213 United States Department of Bioengineering University of California Los Angeles Los Angeles California 90095 United States School of Chemistry Chemical Engineering and Biotechnology Nanyang Technological University Singapore 637457 Singapore Nanobionics Group Department of Chemical and Biological Engineering Monash University Clayton Australia 3800 Monash

Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze continued...challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative

关键词： soft materials mechanics engineering flexible electronics conformable sensors bioelectronics human-machine interfaces body area sensor networks technology translation sustainable electronics

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