An ultrasonic approach for contact stress mapping in machine joints and concentrated contacts
- 1 May 2004
- journal article
- research article
- Published by SAGE Publications in The Journal of Strain Analysis for Engineering Design
- Vol. 39 (4), 339-350
- https://doi.org/10.1243/0309324041223971
Abstract
The measurement of pressure at a contact in a machine part is important because contact stresses frequently lead to failure by seizure, wear or fatigue. While the interface might appear smooth on a macroscale, it consists of regions of asperity contact and air gaps on a microscale. The reflection of an ultrasonic pulse at such a rough contact can be used to give information about the contact conditions. The more conformal the contact, the smaller is the proportion of an incident wave amplitude that will be reflected. In this paper, this phenomenon has been used to produce maps of contact pressure at machine element interfaces. An ultrasonic pulse is generated and reflected at the interface, to be received by the same piezoelectric transducer. The transducer is scanned across the interface and a map of reflected ultrasound (a c-scan) is recorded. The proportion of the wave reflected can be used to determine the stiffness of the interface. Stiffness correlates qualitatively with contact pressure, but unfortunately there is no unique relationship. In this work, two approaches have been used to obtain contact pressure: firstly by using an independent calibration experiment, and secondly by using experimental observations that stiffness and pressure are linearly related. The approach has been used in three example cases: a series of press fitted joints, a wheel/rail contact and a bolted joint.Keywords
This publication has 6 references indexed in Scilit:
- The Use of Ultrasound in the Investigation of Rough Surface InterfacesJournal of Tribology, 2000
- A study of the interaction between ultrasound and a partially contacting solid—solid interfaceProceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 1996
- Contact MechanicsPublished by Cambridge University Press (CUP) ,1985
- The ultrasonic pulse-echo technique as applied to adhesion testingJournal of Physics D: Applied Physics, 1973
- An utrasonic study of the area of contact between stationary and sliding surfacesProceedings of the Royal Society of London. Series A - Mathematical and Physical Sciences, 1971
- The Pressure Distributions between Bolted Plates : On the Stiffness FactorsTransactions of the Japan Society of Mechanical Engineers, 1965