An experimental and signal analysis workflow for detecting cold-induced noise emissions (cold squealing) from porous journal bearings

Abstract

We employ a variant of the joint time-frequency analysis (JTFA) for identifying transient, temperature-dependent noise emitted from porous journal bearings operated at temperatures between -40°C and 0°C. This phenomenon, called "cold squealing", is difficult to reproduce in laboratory environments, as it requires a suitable (and typically system-specific) resonator to occur. We systematically tested real-world bearings impregnated with various oils on a custom-designed experimental rig, fitted with a coolable sample holder and a vibration sensor, over a range of rotational speeds. By analyzing temperature-differential JTFA signal maps, we succeeded in detecting transient cold-squealing as well as ranking the bearing lubricants according to their low-temperature quiet running properties.

An experimental framework for determining wear in porous journal bearings operated in the mixed lubrication regime

“…As an additional means of tracking the running-in of the system, four consecutive Stribeck curves [22] are recorded after 1, 2, 3, 4, 5,8,11,14,17,20,28,36, and 44 h of mixed lubrication operation, which adds an extra 2.5 h of duration to the entire test procedure. The associated rotational speed profile shown in Fig.…”

“…Previous studies by some of the authors focusing on the hydrodynamic operation regime of PJBs [16] or on special phenomena such as cold-squealing [17] have been carried out on a dedicated porous bearing tribometer (SLPG). However, this device can only test one bearing at a time, and since wear tests usually run for several days, a simple but robust device was needed that can wear down several bearings in parallel, thus ensuring comparable operating conditions.…”

Comprehensive review of tribometer dynamics-Cycle-based data analysis and visualization

“…TFA is used for a wide range of applications, including tool condition monitoring [26], fault diagnostics in water pipelines [27], and machinery fault diagnostics [28]. Recently, the authors performed TFA to detect cold-induced noise emissions from porous journal bearings [29]. Previous studies pertaining to the application of TFA to tribological questions are limited to data obtained from non-standard sensors, such as acoustic emissions and laser Doppler vibrometers [30,31] or piezoelectrical vibration sensors [29].…”

A tribometer and methodology for wear and friction testing of porous journal bearings at elevated temperatures

“…Most bearing test devices, e.g. the SLPG tribometer (Neacşu et al , 2016; Eder et al , 2019), are only able to test one setup at a time, and any effort to statistically validate the results of tests that run for at least several days becomes tedious. For this reason, a tribometer was selected that already satisfies the demand of being able to test several bearings in parallel, the “Multiple bearing wear tribometer” (henceforth referred to by its German acronym “MSVT” – “Mehrfach-Sinterlager-Verschleiß-Tribometer”) (Eder et al , 2018).…”