Severity estimation of cracked shaft vibrations within fluid film bearings

Journal Article · Sat Jul 01 04:00:00 EDT 1995 · ASLE Transactions

OSTI ID:117688

Prabhu, B S; Sekhar, A S ^[1]

---

1. Indian Institute of Technology, Madras (India)

The equations of motion, with four degrees of freedom, taking into consideration the flexibility, damping and cross coupling of the fluid film bearings are derived for a cracked Jeffcott rotor supported on fluid film bearings. Dimensionless equations are developed for dynamic radial load, dynamic pressure developed in the fluid film bearings and coefficient of dissipation considering the journal vibrations in two harmonics; bearing fluid film stiffness and damping coefficients. These are applied to a cracked Jeffcott rotor supported on different types of bearings, i.e., cylindrical journal bearings, offset cylindrical bearings, tilting pad journal bearings and three-lobe bearings. Based on the allowable dynamic pressure developed in the fluid bearings, the severity of cracked shaft and allowable crack depths are estimated in this study. Measurement of dynamic pressure and dissipation for monitoring the crack growth is suggested. However, 2x vibration is the best indicator of cracks in the shafts.

• OSTI ID: 117688
• Journal Information: ASLE Transactions, Journal Name: ASLE Transactions Journal Issue: 3 Vol. 38; ISSN ASLTA2; ISSN 0569-8197
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
42 ENGINEERING
CRACK PROPAGATION
DAMPING
HYDROSTATIC BEARINGS
MATHEMATICAL MODELS
MECHANICAL VIBRATIONS
PRESSURE MEASUREMENT