学术报告
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时间:2018年11月22日 9:30~12:00

地点:大学城校区工学2号馆202会议室

报告一:Novel Cryogenic Processing of Materials for Improved Functional Performance of Components in Automotive, Aerospace and Biomedical Applications

报告人:Professor I.S.Jawahir

报告人简介:

Professor Jawahir’s current research interests focus on predictive modeling and optimization of machining processes and sustainable product design and manufacturing processes. His early pioneering work on dry, near-dry (also known as MQL) and cryogenic machining/processing of materials, and the more recent foundational work on sustainable manufacturing are well-recognized. He referred journal papers, and has been awarded with 4 U.S. patents. He has delivered 60 keynote papers in major international conferences and over 150 invited presentations in 36 countries.

Professor Jawahir is a Fellow of three major professional societies: CIRP (International Academy for Production Engineering); ASME (American society of Mechanical Engineering); and SME (Society of Manufacturing Engineers). He is the Founding Editor of the Journal of Machining Science and Technology. Professor Jawahir founded the CIRP International Conference Series on Modeling of Machining Operations in 1998, and this conference series still continues and the 17th conference in this series will be held in Sheffield, United Kingdom in June 2019. Professor Jawahir founded the CIRP Conference Series on Surface Integrity in 2012. He has also been serving as a Gounding Menber of another successful CIRP-sponsored major international conference series-Global Conference on Sustainable Manufacturing (GCSM). In October 2018, Professor Jawahir organized and hosted the 16th conference in this series in Lexington, KY, USA and served as the Conference Chairman.

Professor Jawahir received numerous awards over the years, including the 2013 ASME Milton C. Shaw Manufacturing Research Medal for his outstanding research contributions to fundamental understanding of sustainable manufacturing processes, and the 2015 William Johnson International Gold Medal for his lifelong achievements and contributions to materials processing research and education. In May 2017, Professor Jawahir was also named as a 2017 University Research Professor at the University of Kentucky.

讲座摘要:

Cryogenic processing of materials is known to be among the most sustainable novel manufacturing methods because of its environmentally benign, and economically and societally-beneficial nature. Sustainable manufacturing processes are generally aimed at achieving energy-efficiency, environmental friendliness (with reduced negative environmental impact), cost-effectiveness, waste/coolant reduction or elimination, operational safety and reliability, along with no adverse personnel health effects to operators and shop floor personnel.

This presentation will summarize recent progress in cryogenic processing of a range of materials (Ti alloys, Ni-Ti shape memory alloys (SMAs), Inconel 718, AISI 52100, AISI 316L, AISI 419, AA 7050, AA 7075, AZ31B Mg alloys, Co-Cr-Mo alloys, CFRP, etc.) for achieving enhanced surface and sub-surface integrity to provide improved product quality, performance and life. This study includes an analysis of severe plastic deformation (SPD) induced by cryogenic machining and bumishing processes on some of these materials, and their resulting performance enhancement through controllable ultra-fine/nano grain structures, and the associated wear and corrosion resistance properties, and the induced compressive residual stresses enabling improved fatigue life in some of these machined and burnished materials.

Recent advances in modeling and optimization of cryogenic machining processes will then be discussed. Experimental results are compared with numerical/analytical simulations. Encouraging findings from this extensive study shows the tremendous potential for applications in automotive, aerospace and biomedical industries. This presentation will also discuss new challenges for such industry applications.

报告二:Strategies for Designing High Performance Coatings for Cutting Tools– Success Stories from RWTH Aachen University

报告人: Dr. Ing. Tobias Brögelmann

报告人简介:

Dr.-Ing. Tobias Brögelmann works as chief engineer and deputy head at Surface Engineering Institute (IOT) of RWTH Aachen University, Germany. He is responsible for the thin film division including the R&D departments PVD Technology Tools and PVD Technology Components. His R&D work on thin film technology is focused on fundamental and application-oriented research and development of coatings for protection and functionalization of tools and components in the automotive and aviation sector, in production and manufacturing technology, in energy technology as well as in general mechanical engineering. He studied Materials Science (B.Sc. and M.Sc.) at RWTH Aachen University, and received his doctorate in Mechanical Engineering at RWTH Aachen University with distinction. He is member of the body of experts within the research field “Tribology“ of the Federal Ministry of Economic Affairs and Energy (BMWi) and Project Management Juelich (PtJ), Germany, and member of the DIN Working Committee “Carbon-based Films and Ceramic Hard Coatings“ within the DIN Standards Committee Materials Testing (NMP). He has more than 100 publications and serves as reviewer for many scientific journals. He is involved in the organization committees of national and international conferences.

讲座摘要:

Nanostructured functional coatings based on a nanocrystalline, -laminate, or -composite structure open new paths to design high performance coatings for cutting tools with tailor made properties to meet the requirements from high speed cutting, high performance cutting, and dry machining of challenging workpiece materials. High performance plasmas, such as high power pulsed magnetron sputtering (HPPMS) provide a complex deposition parameter set to control the structure on nanometer scale and adjust the coating properties. However, reaching the full potential of the process technology and the nanostructured coating requires fundamental understanding and full control of the deposition process, in particular when using an industrial scale coating unit with a multi-fold rotating substrate holder. Therefore, cutting tools are an excellent example for how the development of coated products is traced methodologically by means of a holistic view over the application.

In this plenary talk, highlights of cooperative research and development at Surface Engineering Institute of RWTH Aachen University on nanostructured PVD coatings for use in machining will be presented. The plasma in reactive HPPMS and dcMS/HPPMS hybrid processes is investigated by space- and time-resolved plasma diagnostics. Further investigations are focusing on the relationship among pulse parameters and coatings properties, such as chemical composition, intrinsic stress and elastic-plastic behavior. Correlations between the plasma properties, the pulse parameters, such as pulse length, frequency, and pulse power, and the coating properties are the basis for process and coating adjustment to the demands in machining. Cutting tests at Laboratory for Machine Tools and Production Engineering (WZL) and at Fraunhofer Institute for Production Technology (IPT) of RWTH Aachen University reveal great potential of nanostructured coatings. In order to overcome the empirical approach on the synthesis path of nanostructured coatings in high performance plasmas, artificial intelligence (AI) is used to describe highly non-linear or multidimensional cause-effect relationships between process parameters and properties of the coated tool.

报告三:Towards frictionless mechanical contacts

报告人:Dr.Filipe Daniel Fernandes

报告人简介:

Filipe Fernandes is now an invited assistant professor in the mechanical engineering department of the university of Coimbra; and post-doc researcher fellow at the GRF-CFUM Research Centre at the University of Minho and Control engineering department of the Czech technical University in Prague in the aim of the grant awarded by FCT (SFRH/BPD/116334/2016). Individual project entitled: “Machinability improvement of Ti alloys through Ti-Si-N(Ag) self-lubricant coatings with optimized Ag contents”. He developed different coating systems deposited by dissimilar processes (PTA, HVOF, APS and PVD) for protecting the molds used for the production of glass bottles. He also contributed to the development novel TiSiVN self-lubricant materials for high temperature applications, multicomponent materials TiAlN/CrAlN to protect and extend the lifetime of cutting tools. In last five years, he has 13 publications in the international journals “Surface coatings Technology”, “tribology international”, “Wear”, “Thin solid film” and “Applied surface science”. He is also project leader in several industrial projects and fundamental research projects.

讲座摘要:

Automotive windshield glazing is a sandwiched structure, which consists of two soda-lime glass layers bonded by a plastic interlayer, PVB. Though it is very simple, the windshield glazing is considered to be an important safety component for a vehicle, and it is of vital importance to investigate its damage and energy absorption behavior for the purpose of pedestrian safety protection. To achieve this end, several state-of-the-art numerical technologies, e.g. discrete element method (DEM), finite element method (FEM) and coupling DEM/FEM method, were employed to investigate the fracture behaviors of this sandwiched structure in this presentation. The fracture process of the laminated glass under headform impact is simulated. The effectiveness of the proposed windshield model is validated by comparing the simulation results, such as crack patterns, headform acceleration, etc., with the corresponding experimental outcomes. Besides, the effects of adhesion parameters, PVB material parameters, and impact velocities and angles on the impact failure behavior of windshield glazing are thoroughly investigated. Although this presentation focuses on the impact fracture behaviors of the laminated glass, these approaches proposed are not restricted to this, and theoretically can be used to solve other brittle materials fracture problems, e.g. ceramics, rocks and concrete, etc.