Thermal analysis of an LPV test-rig

A material property which is often used in the comparison and selection of polymer based materials used for dry rubbing journal bearings is the Limiti ng Pressure-Velocity (LPV) value. In a large pressure and velocity range th is value is determined by the maximum temperature and compressive strength in the contact area. The temperature is related to the amount of heat gener ated in the contact area between shaft and bearing and the total thermal re sistance from that contact area to the ambient atmosphere. This thermal res istance is therefore not only determined by the bearing itself but also by the assembly as a whole in which that bearing has been used. The LPV-value for a particular material measured on a particular test-rig i s therefore dependent on the thermal resistance of that test-rig and cannot be compared directly with an LPV curve for that same material measured on another test-rig which has a different thermal resistance. In this paper a thermal model is used to calculate the heat generation and transport in an LPV test-rig and the results of this model are verified wit h some experiments. Furthermore it is shown how the material properties such as friction coeffi cient and melting temperature obtained by another material testing method v iz the so-called Finger Print (FP), in combination with the calculated ther mal resistance of the test-rig, can be used to predict LPV-values for a mat erial on that test-rig. (C) 1999 Elsevier Science Ltd. All rights reserved.