3S5: (90 min.) From friction to failure – assessing bearing health using Ultrasound

Tom Murphy , Corporate Training Manager, SDT Ultrasound Solutions


There are eight major application areas for Ultrasound, two of them are friction and rotating machinery. This presentation examines, with numerous examples and case histories, just how easy it is to use ultrasound for on-condition lubrication and early stage bearing failure. The presentation then goes on to demonstrate the seamless integration approach where bearing condition assessment is a free by-product of an on-condition lubrication program.

Ultrasound detects sound generated beyond human hearing. Friction generates noise in this region. Early stage bearing defects are known to generate sound and vibration energy from the audible range up to several 100s of kilohertz. Combining this knowledge suggests that measuring the acoustic behaviour of a bearing in these higher, ultrasonic, frequencies provides valuable insight into the frictional state of a bearing and also into the presence of any high frequency impacts which for decades have been known to be a strong indicator of early failure.

In the last three decades, ultrasound has developed from a listen-only technology into a listen, measure and analyse technology. Now we can not only hear that a bearing has high friction but we can also listen as we apply lubrication to that bearing, trend that data to prove that the lubrication was beneficial and analyse that data to identify defects.


Name: Thomas J. Murphy

Resident: Manchester, England

Job Title: Managing Director, Reliability Team Limited; SDT International Training Manager

Education: Bachelor degree in Electroacoustics, University of Salford

Status: Member of Institute of Acoustics (MIOA); Chartered Engineer (C. Eng.); Certified Reliability Leader (CRL

Experience: 34 years experience in the application of noise and vibration to a wide range of industry around the world; 22 years experience in infrared technology; 17 years experience in ultrasound; Facilitator in FMEA and RCA projects

Current work: ASNT Level 1 and Level 2 ultrasound trainer; ISO TC108 national technical representative; Implementation training on ultrasound and predictive programmes to industry around the world.

Author: Co-author, Murphy, T.J., Rienstra, A.A, Hear More, A Guide to Using Ultrasound for Leak Detection and Condition Monitoring. ISBN-13: 978-0982516331; Technical papers and articles presented and printed in many countries around the world.