题目：Nonlinear Dynamics and Stability in Machining Processes
时间：2024年11月30日 10:00-11:30
地点：suncitygroup太阳新城官网 F210会议室
邀请人：瞿叶高 教授（振动、冲击、噪声研究所）
Biography
Professor Marian Wiercigroch educated in Poland, US and UK holds a prestigious Sixth Century Chair in Applied Dynamics and he is a founding director of the Centre for Applied Dynamics Research at the University of Aberdeen.
His area of research is theoretical and experimental nonlinear dynamics, which he applies to various engineering problems. Wiercigroch has published extensively (over 500 journal and conference papers) and sits on a dozen editorial boards of peer review journals. He is a frequent keynote and plenary speaker at major international conferences and the Editor-In-Chief of International Journal of Mechanical Sciences, a leading journal in mechanics and mechanical engineering.
He is the inventor of new patented drilling technology called Resonance Enhanced Drilling and the Founder and Chief Technology Officer of a spinoff company iVDynamics Ltd. He has established in Aberdeen unique experimental laboratories allowing to investigate complex nonlinear dynamic interactions in mechanical systems with the focus on energy generation.
Marian is a Scottish Champion of Knowledge Exchange (2020) and he served as a panelist in the Research Excellence Framework (2014, 2021), which assess the quality of research in the UK. He has received many awards and distinctions including a Senior Fulbright Scholarship (1994), Fellowship of the Royal Society of Edinburgh (2009), DSc honoris causa from the Lodz University of Technology (2013), Distinguished Honorary Professorships from the Perm National Research Polytechnic University (2017), Balseiro Institute (2018), Yanshan University (2021) and University of Nottingham Ningbo (2023).
Abstract
Comprehensive understanding of chatter, bifurcations and stability is essential for improving productivity, quality, and efficiency of manufacturing operations. Chatter manifests itself as undesired large amplitude self-excited vibration, whilst bifurcation and stability analysis hold the keys to its effective control and suppression. Bifurcations in manufacturing occur when processing and system parameters cross certain values and(or) they are results of complex interactions resulting predominantly in creating or disappearance of limits cycles. Bifurcations in manufacturing processes belong to the most complex ones, where nonlinearities are very strong and play the dominant role e.g. Process stability is vital to ensure high-quality surface finish, dimensional accuracy, and extended machine and tool life.
In this lecture, first I will define nonlinearity, chatter, bifurcations and stability in manufacturing processes with the focus on metal cutting. Then I will discuss on the frictional chatter, which was introduced and investigated with my group and collaborators (see e.g.). Chatter in precision grinding has been a subject of many our investigations, where low dimensional strongly nonlinear models were used to undertaken in depth analytical and numerical studies, see for example. Finally, examples of advanced nonlinear dynamics techniques such as path following bifurcation analysis, basins of attraction, Poincare maps and Lyapunov exponents will be discussed, which have been used to examine stability and determine a practically important measure so-called cutting safety.
