Coupled Torsional and Transverse Vibration of a Back-to-Back Gearbox Rig

Abstract The coupled torsional and transverse vibration of a back-to-back gearbox system has been investigated experimentally and analytically. Receptance methods were used to model the system, and were shown to be effective. A detailed experimental modal analysis was performed using the swept-sine technique with an a.c. servomotor torsional exciter. Torsional excitation allowed for the dynamic response to be measured up to 1600 Hz. The model included a combination of lumped mass elements and continuous shafts with distributed inertia and damping. The bearings were modelled as having both radial and tilt stiffness and damping elements. The model simulated the experimental results well and predicted each of the first 11 natural frequencies to within 8 per cent. Of the 11 natural frequencies, 9 simulated deflected shapes matched very well, validating the modelling approach taken for the project together with the assumptions made in the derivation of the model. This paper presents the detailed results of a full torsional/transverse model analysis of the gearbox system.

[1]  K. Urlichs,et al.  Dynamic Gear Loads Due to Coupled Lateral, Torsional and Axial Vibrations in a Helical Geared System , 1999 .

[2]  Harold R. Simmons,et al.  Lateral Gear Shaft Dynamics Control Torsional Stresses in Turbine-Driven Compressor Train , 1984 .

[3]  B. Stone,et al.  The torsional vibration of a damped continuous bar , 1996 .

[4]  H. Iida,et al.  Dynamic Characteristics of a Gear train System with Softly Supported Shafts , 1986 .

[5]  Brian Stone,et al.  Torsional damping of a back-to-back gearbox rig: Experimental measurements and frequency domain modelling , 2002 .

[6]  Donald R. Houser,et al.  Dynamic analysis of geared rotors by finite elements , 1992 .

[7]  J. W. Lund.  Critical Speeds, Stability and Response of a Geared Train of Rotors , 1978 .

[8]  B. J. Stone.  The State of the Art in the Measurement of the Stiffness and Damping of Rolling Element Bearings , 1982 .

[9]  H. Iida,et al.  Coupled Torsional-flexural Vibration of a Shaft in a Geared System of Rotors : 1st Report , 1980 .

[10]  Singiresu S Rao,et al.  Dynamic Load Analysis of Spur Gears Using a New Tooth Profile , 1996 .

[11]  E Y K Ng,et al.  Prediction of skin burn injury. Part 1: Numerical modelling , 2002, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[12]  Hiroshi Iida,et al.  Coupled Torsional-flexural Vibration of a Shaft in a Geared System : 3rd Report, Dynamic Characteristics of a Counter Shaft in a Gear Train System , 1985 .

[14]  S. J. Drew,et al.  Torsional vibration of a back-to-back gearbox rig Part 2: Time domain modelling and verification , 2000 .

[15]  S. J. Drew,et al.  TORSIONAL (ROTATIONAL) VIBRATION: EXCITATION OF SMALL ROTATING MACHINES , 1997 .