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Modeling and Stability Analysis of Robot-assisted Thin-walled Milling

IFAC-PapersOnLine 2023年第2期56卷 6314-6319页

作者： Woraphrut Kornmaneesang Tsu-Chin Tsao Shyh-Leh Chen International Bachelor Program in Engineering Yuan Ze University Taoyuan Taiwan Mechanical and Aerospace Engineering Dept. University of California Los Angeles Los Angeles CA 90095 Mechanical Engineering Dept. and Advanced Institute of Manufacturing with High-tech Innovations National Chung Cheng University Chiayi Taiwan

Thin-walled machining has played an important role in automotive and aerospace domains. Due to physical characteristics of the flexible structure, the thin-walled machining is prone to the deformation and the onset of chatter. To solve the problem, a robot is considered to support the flexible workpiece while cutting. This paper studies finite element dynamic modeling and stability analysis of the robot-assisted thin-walled milling system. It is divided into three submodels: thin-walled workpiece, robot, and cutting process. The finite element method (FEM) is adopted to obtain a realistic dynamic model of the workpiece and allows analysis of any location. The robot dynamics is linearized to a 1-degree-of-freedom (DOF) mass-spring-damper system for model reduction. The cutting force variation and the regenerative effects involved in the cutting process establish time-periodic and time delay terms in the milling model. The semi-discretization method (SDM) is used for the stability analysis. Simulation results show a significant improvement in the milling stability from the robot support in any location, leading to higher productivity.

关键词： vibration control smart structures robot manipulators stability of delay systems systems with time-delays time-varying systems

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Effect of Parasitic Leakage Currents Associated with the Regrown Aperture of AlGaN/GaN Current Aperture Vertical Electron Transistors (CAVETs)

Effect of Parasitic Leakage Currents Associated with the Reg...

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IEEE Electron Devices Technology and manufacturing Conference (EDTM)

作者： Sara Pouladi Jae Hyun Ryou Department of Mechanical Engineering Texas Center for Superconductivity at UH Advanced Manufacturing Institute University of Houston USA Department of Electrical and Computer Engineering Materials Science and Engineering Program University of Houston USA

We present a numerical simulation on the effect of leakage paths in the regrown GaN layer in the aperture and above the current blocking layer (CBL) of current aperture vertical electron transistor (CAVET) devices. Here, a 2D TCAD modeling is employed to simulate a CAVET device structure considering two main origins of parasitic leakage current from CBL/regrown-GaN interface and gate/regrown-GaN bulk and their degree of detrimental effect on the characteristics of AlGaN/GaN CAVETs.

关键词： Performance evaluation Apertures Logic gates Numerical simulation Wide band gap semiconductors Numerical models Leakage currents

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Process Optimization and Scaling of Molybdenum and Tungsten in Additive manufacturing Techniques

SSRN

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SSRN 2024年

作者： Islam, Zahabul Kunkel, William Hatler, Caleb Thoma, Dan J. Mechanical and Manufacturing Engineering Program School of Engineering Bowling Green State University Bowling GreenOH43403 United States Alloy Design and Development Laboratory Department of Materials Science and Engineering University of Wisconsin MadisonWI53706 United States

Metal additive manufacturing processes pose a daunting challenge in defining optimal process parameters that yield porosity defect-free, dense parts. This is particularly true in refractory metals, where high melting temperatures limit process parameter windows. This present study investigates a dimensionless number analysis that has been derived through the Buckingham-PI theorem and demonstrates a robust correlation between process parameters and the density of the fabricated components. The introduction of this dimensionless number enables the initial estimation of process parameters without extensive modeling or experimentation. Additionally, a universal scaling law is proposed to enhance the translation of predicting process parameters for achieving an optimal density in as-built parts between different processing techniques. A combination of this proposed dimensionless number and scaling law offers process maps for tungsten and molybdenum with previously unknown process parameters. The universality of the proposed dimensionless number also demonstrates transferability, enabling the prediction of process parameters both for laser powder bed fusion and directed energy deposition systems. © 2024, The Authors. All rights reserved.

关键词： 3D printing

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Configuration blade shape for enhancement crossflow turbine performance by the CFD method

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International Journal of Thermofluids 2024年 22卷

作者： Adanta, Dendy Sari, Dewi Puspita Syofii, Imam Thamrin, Ismail Yani, Irsyadi Marwani Fudholi, Ahmad Prakoso, Aji Putro Department of Mechanical Engineering Faculty of Engineering Universitas Sriwijaya Ogan Ilir South Sumatera30862 Indonesia Study Program of Mechanical Engineering Education Faculty of Teacher Training and Education Universitas Sriwijaya Ogan Ilir South Sumatera 30862 Indonesia Serpong15314 Indonesia Solar Energy Research Institute Universiti Kebangsaan Malaysia Selangor Bangi43600 Malaysia Department of Mechanical Engineering Faculty of Manufacturing Technology Universitas Jenderal Ahmad Yani West Java Cimahi Indonesia

The pico scale crossflow turbine (CFT) is a prospect as an independent power plant for remote and rural areas because it has a stable efficiency range of 64 % to 79.5 % in high discharge fluctuation. An alternative to CFT performance enhancement is determining the upper blade configuration to increase lift force. Hence, this study investigates four configurations of the upper CFT blade: convex blade at the centre edge, convex at the trailing edge, convex at the leading edge and ordinary curvature. This research employs a computational fluid dynamics (CFD) method to visualise the flow field. The upper CFT blade configuration significantly affects its performance, and convex at the leading edge has higher performance than others. The performance related to each blade shape's specific speed is parabolic and expressed using empirical law. The empirical law recommends 4.88 as specific speed for designing a pico scale CFT. © 2024 The Author(s)

关键词： Turbomachine blades

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Highly Flexible Piezoelectric Pressure Sensor at Extremely High-Temperature Range Using Ultrawide-Bandgap III-N Thin Films

Highly Flexible Piezoelectric Pressure Sensor at Extremely H...

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IEEE Electron Devices Technology and manufacturing Conference (EDTM)

作者： Nam-In Kim Miad Yarali Muhammad Aqib Jae-Hyun Ryou Department of Mechanical Engineering Texas Center for Superconductivity at UH Advanced Manufacturing Institute University of Houston USA Materials Science and Engineering Program University of Houston USA Department of Electrical and Computer Engineering University of Houston USA

Pressure monitoring in extreme conditions, such as in industrial, aerospace, and radioactive atmosphere, is crucial. Our focus is on developing and researching piezoelectric sensors that are highly flexible for detecting gas pressures at extremely high temperatures. We develop the flexible device using epitaxial III -nitride film, which is single-crystalline, by layer-transfer method. The sensor shows a sensitive and stable operation for extended periods. We use software simulation and relevant formulas to support our experimental findings.

关键词： Temperature sensors Pressure sensors X-ray scattering Sensor phenomena and characterization Software Semiconductor process modeling III-V semiconductor materials

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Current Issues in Flexible manufacturing Using Multicriteria Decision Analysis and Ontology Based Interoperability in an Advanced manufacturing Environment 10th

Current Issues in Flexible Manufacturing Using Multicriteria...

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10th International Conference of Production Research - Americas, ICPR-Americas 2020

作者： Canciglieri, M.B. Leite, A. F. C. S. de M. Rocha Loures, E. de F. Canciglieri, O. Monfared, R.P. Goh, Y.M. Industrial and Systems Engineering Graduate Program Pontifical Catholic University of Paraná Curitiba Paraná Brazil School of Mechanical Electrical and Manufacturing Engineering Loughborough University Loughborough Leicestershire United Kingdom

ISBN: (纸本)9783030763060

The manufacturing industry is undergoing a major transformation based on the emerging industry 4.0 technologies, such as cloud computing, big data, internet of things and cyber-physical systems. These novelty technologies aim at providing central management for the user’s flexible manufacturing requirements and information. Also, the advent of these technologies has transformed the process planning and became crucial for the building of knowledge-based process planning environments. However, current praxis cannot deal with all semantic issues within this new paradigm, as requirements must be clear, consistent, measurable, stand-alone, testable, unambiguous, unique and verifiable. In this context, multicriteria decision analysis models have gained focus of the scientific and industrial communities as a support tool for the decision-making process in the product development and advanced manufacturing as these processes excel in environments with numerous and conflicting alternatives, providing the optimal alternative. Therefore, the main objective of this research is to highlight the current issues and research tendencies regarding ontology-based interoperability systems, multicriteria decision analysis and their integration. To achieve this goal, it will be applied a literature review on the targeted technologies, discussing the current tendencies of the field and the main issues regarding their implementation and integration. Finally, the paper points themes for further research and indicates viable concepts that can compose a solution for the gaps in a systematic manner. © 2021, Springer Nature Switzerland AG.

关键词： Flexible manufacturing systems

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Wear of silicon carbide wheel during grinding of intermetallic titanium aluminide

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International Journal of Machining and Machinability of Materials 2020年第2期22卷 122-136页

作者： Mathew, Nithin Tom Vijayaraghavan, L. Mechanical Engineering Department Work Integrated Learning Program Division BITS Pilani Rajasthan333031 India Department of Mechanical Engineering Manufacturing Engineering Section Indian Institute of Technology Madras Chennai600036 India

An experimental investigation is reported on the wear of silicon carbide wheel and its influence on the wheel topography and grinding behaviour during the surface grinding of high performance intermetallic gamma titianium aluminide. The radial wear of the wheel was characterised by initial transient state followed by a steady state wear regime and finally a steel rise in wear rate. The initial transient region progressed up to a radial wear of 40 µm. The normal and tangential forces remained approximately constant up to about 25 µm wheel wear and subsequently progressively increased to a maximum at 60 µm wear. The specific energy began approximately at about u = 140 J/mm3 and started progressing beyond radial wear of 25 µm and increased up to 600 J/mm3 at wear of 60 µm. There was high initial roughness value with the fresh wheel with a progressive decrease with continued grinding. There was noticeable increase in roughness value after a radial wear of 60 µm. With the progress of wear there was presence of surface burns, chatter marks and cracking. The presence of blue oxide discoloration was observed during the visual inspection signifying the generation of reasonably high temperature. Copyright © 2020 Inderscience Enterprises Ltd.

关键词： Silicon carbide

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Synthesis and characterization of a dithiodiglycolic acid-incorporated poly(glycerol sebacate) exhibiting lipase resistance and antibacterial properties

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European Polymer Journal 2024年 214卷

作者： Jiang, Yi-Sheng Hu, Ming-Hsien Hu, Jin-Jia Jan, Jeng-Shiung Department of Chemical Engineering National Cheng Kung University Tainan70101 Taiwan Bachelor Program for Design and Materials for Medical Equipment and Devices Da-Yeh University Changhua515 Taiwan Orthopedic Department Showchwan Memorial Hospital Changhua 500 Taiwan Department of Mechanical Engineering National Yang Ming Chiao Tung University Hsinchu300 Taiwan Program on Smart and Sustainable Manufacturing Academy of Innovative Semiconductor and Sustainable Manufacturing National Cheng Kung University Tainan70101 Taiwan

Poly(glycerol sebacate) (PGS), a crosslinked network synthesized by polycondensation of glycerol and sebacic acid, has found successful utilization in various tissue engineering applications because of its biocompatibility, ease of synthesis, surface-erosion biodegradability, rubber-like elasticity, and adjustable mechanical properties. However, its fast in vivo degradation and lack of intrinsic antibacterial activity may be a concern for specific applications. The functional groups of glycerol and sebacic acid can react with those of other monomers, offering unlimited possibilities for generating new crosslinked networks tailored for particular purposes. Herein, we synthesized a series of poly(glycerol sebacate dithiodiglycolate) (PGSDTG) by incorporation of dithiodiglycolic acid (DTG) in the synthesis of PGS. PGSDTG exhibited reduced stiffness, sensitivity to glutathione (GSH), resistance to lipase degradation, and inhibition of bacterial adhesion and growth. The PGSDTG containing 45.6 wt% of DTG exhibited the lowest degradation rate with more than 80 wt% of PGSDTG remained at day 28 and the lowest bacterial inactivation rates of 99.2 ± 0.5 % and 82.5 ± 11.0 % against S. aureus and E. coli, respectively. This study suggested that PGSDTG may serve as a suitable antibacterial scaffold material for repairing or regenerating tissues characterized by a slow healing rate. © 2024 Elsevier Ltd

关键词： Glycerol

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Influence of gradation in the reinforcement particles on the interfacial microstructure and mechanical properties of functionally graded composites

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Materials Today Communications 2024年 38卷

作者： Karakoç, Halil Çinici, Hanifi Saravana Kumar, M. Yılmaz, Tolga Ovalı, İsmail Yang, Che-Hua Arjunan, Arun Department of Mechanical Program Hacettepe University Ankara06935 Turkey Department of Metallurgy and Materials Engineering Gazi University Ankara06500 Turkey Graduate Institute of Manufacturing Technology National Taipei University of Technology Taipei10608 Taiwan Department of Manufacturing Engineering Pamukkale University Denizli20160 Turkey Group centre for Engineering Innovation and Research University of Wolverhampton TelfordTF2 9NT United Kingdom

In this research, Al6061 alloy-based Functionally Graded Composites (FGCs) were fabricated by hot pressing which is composed of 7 layers with different proportions of Al2O3 reinforcement particles. The addition of Al2O3 particles is gradually increasing in the other layers from top to bottom (Layer 1 - Pure Al6061 alloy, Layer 2–5 wt% Al2O3, Layer 3–10 wt% Al2O3, Layer 4–20 wt% Al2O3, Layer 5–30 wt% Al2O3, Layer 6–40 wt% Al2O3, Layer 7–50 wt% Al2O3). Moreover, three different Al2O3 particle sizes (8, 16 and 32 µm) were used to fabricate three sets of FGCs. Reciprocating wear studies were performed and the result shows that the FGC with 8 µm Al2O3 particle size shows 85.5% improved wear resistance. Further, various wear mechanisms were investigated and finally compressive strength analysis proved that the homogenous distribution of Al2O3 particles in the FGC with 16 µm Al2O3 particle size helps achieve the maximum compression stress of 476.04 MPa compared with other FGCs. © 2023 Elsevier Ltd

关键词： Compression testing

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Defect-driven relaxation of nanostructured Cu examined by in situ heating high-energy synchrotron X-ray microbeam diffraction

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Journal of Alloys and Compounds 2025年 1028卷

作者： Lee, Isshu Bhatta, Laxman Xu, Donghua Blankenburg, Malte Lienert, Ulrich Liss, Klaus-Dieter Kawasaki, Megumi Materials Science Program Oregon State University CorvallisOR97331 United States School of Mechanical Industrial and Manufacturing Engineering Oregon State University CorvallisOR97331 United States Hamburg22607 Germany University of Tennessee Oak Ridge Innovation Institute KnoxvilleTN37996 United States

Bulk nanostructured metals introduced by severe plastic deformation contain an excess of lattice defects. A nanostructured copper (Cu) processed by a high-pressure torsion technique was examined during in situ heating to investigate microstructural relaxation and quantify the evolution of microstructural parameters using high-energy synchrotron microbeam X-ray diffraction. While general microstructural relaxations, such as recovery, recrystallization, and subsequent grain growth, were observed, the key microstructural parameters, including grain size, microstrain, dislocation density, and thermal expansion coefficient, and their changes at critical temperatures were uniquely described and quantified through diffraction data. Based on this analysis, the stored energies driving thermally activated microstructural changes were estimated for individual defect types — grain boundaries, dislocations, and vacancies — that are expected to significantly influence the relaxation behavior of nanostructured Cu. This study demonstrates the effectiveness of diffraction characterization techniques for gaining a comprehensive understanding of the thermal stability of bulk nanostructured materials. © 2025 Elsevier B.V.

关键词： Dislocations (crystals)

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