Speaker: Mr. Nicolas Peton
Mr. Nicolas Peton is the global director of Machinery Diagnostic Services group in General Electric - Bently Nevada. He joined GE in 2006 in the Machinery Diagnostic Services group. Previously he worked for two different manufacturers (Alstom Steam turbine and Cryostar expander/compressor) where he was in charge on site of the startup activities worldwide. He also worked as an operation and maintenance engineer in the chemical industry (PPG industry, USA) and as Free Lance for startup activities worldwide. He has been also a mechanical/acoustical research engineer in research institutes (Technion, Haifa and TU Berlin) . He is currently MDS Global Director for the Machinery Diagnostic Services. He has a Diplome d’ingénieur from the Université de Technologie de Compiègne, France and he is now working on his PhD.
Bently Nevada is globally renowned for rotor dynamics and rotating machinery diagnostics. This presentation gives an introduction to vibrations in rotating machines and vibration measurement for detection of a malfunction. Detailed case studies are given in the presentation: 1) Case study of a single shaft combined cycle turbine-generator unit, where torsional vibration conversion mechanism and self-excited vibration mechanism are discussed; 2)Case study of an 110MW generator driven by a gas turbine through speed reduction gearbox, where malfunctions causing the 2X elevated vibration response are discussed in detail; 3)Application of Operating Deflection Shape (ODS) analysis is presented; 4) machinery rubs and their causes.
Speaker: Dr. John J. Yu
Dr. John J. Yu is the senior technical manager of Machinery Diagnostic Services group in General Electric - Bently Nevada. After obtaining his PhD in Mechanical Engineering from University of Alberta in 1997, he joined Bently Rotor Dynamics Research Corporation, followed by General Electric - Bently Nevada in 2002. He obtained his BSME and MSME from Shanghai Jiao Tong University. He has performed not only rotor dynamic research but also machinery vibration diagnostics for customers worldwide. He is a Fellow of the American Society of Mechanical Engineers (ASME), and has served as associate editor of the ASME Journal of Vibration and Acoustics. He received the 2001 John P. Davis Award by ASME IGTI. He has authored numerous technical papers in refereed journals and conference proceedings. He has also served many times as Session Chair for ASME conferences. He has been selected as an Advisory Committee member to the Asia Turbomachinery & Pump Symposium.
This presentation discusses rub, Morton effect, parametric excitation, and shaft crack cases in rotating machines. Rub occurs more often besides unbalance and misalignment. The current rub topic covers all types of rub. The Morton effect has similar vibration pattern as the Newkirk effect, though it occurs not that often. Parametric excitation here is referred to subharmonic behavior such as ½X vibration, due to either rub or bearing looseness. Since ½X is touched here, shaft crack manifested by 2X vibration is also discussed briefly.