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Numerical analyses of the roller-raceway contact have been carried out in a spherical roller bearing using frictional contact models of different complexity. The models used in the study include an implementation of Kalker's exact contact theory named CECT (Conformal Exact Contact Theory) and detailed Finite Element models. The adequacy of the more simplified contact solutions is assessed by contrasting them with the solutions obtained with themore comprehensive models. Additionally, the use of the exact contact theory, well known in the wheel-rail application, is demonstrated in contact mechanics analyses in rolling bearings, describing relevant details of its implementation for this application. Situations with different normal loads and friction levels have been analysed, and two distinct steady equilibrium configurations of the roller have been identified. [ABSTRACT FROM AUTHOR]

Models for the occurrence of the vibrational instability during rolling known as third octave chatter are presented and discussed. An analysis of rolling mill chatter was performed for the purpose of identifying characteristics of the vibrations and to determine any dependency on the rolling schedule. In particular, a stability criterion for the critical rolling speed is used to predict the maximum rolling speed without chatter instability on schedules from a 5 stand tandem mill rolling thin steel product. The results correlate well with measurements of critical speed occurring on the mill using a vibration monitor. This research provides significant insights into the chatter phenomena and has been used to investigate control methods for suppression of the instability. [DOI: 10.1115/1.1456457]

Nuclear magnetic resonance (NMR) spectroscopy and x-ray crystallographic techniques were used to study a group of mercury(II) phosphines using bidentate phosphine ligands that have a dimethylsilicon component. Although the NMR spectra of the complexes were almost the same, differences in chemical shift values were observed which were attributed to the different electronic properties of the ligands. Results also showed the presence of four-coordinate metal centers in the [HgX2.L2] complex.