Precise control of operating conditions in tribotesting with respect to trace humidity and contact temperature

Abstract

Research in tribology are often connected to tribosystems operating in specific environments, where climate chambers are needed for tribotesting to resemble the environmental conditions in the real application. Although the effect of humidity on the tribological performance of many materials and lubricants is evident, many studies are conducted without sufficient systems to accurately monitor and control the humidity level throughout testing. In this paper, a humidity controlling system was developed to enable continuous monitoring and precise control of the humidity at trace moisture levels. The climate controller was validated in a tri-pin-on-disc tribometer with excellent performance and can be fitted to most climate chambers. To further improve the control of operating conditions during tribotesting, a thermodynamic simulation of the contact temperature was developed. The developed climate controller is a simple and cost-effective method to accurately monitor and control the humidity in a climate chamber at trace moisture levels. The portable design of the humidity controller enables use with most climate chambers and enclosed tribometers. To have better control over the temperature in the sliding interface during testing, a thermodynamic simulation method was used to estimate contact temperature between sliding bodies from near-contact temperature measurements and the measured friction forces.

Effect of Oxygen and Moisture on the Friction and Wear of Carbon Fiber-Reinforced Polymers

“…Heaters underneath the counterface are used to control the near-contact temperature to the set value. A detailed description of the tribometer can be found in a previous publication [19]. Due to the low wear rates of the carbon fiber-reinforced materials, the initial conformity between the composite pins and the steel counterface was critical in order to achieve reliable results.…”

“…Heaters underneath the counterface are used to control the near-contact temperature to the set value. A detailed description of the tribometer can be found in a previous publication [19].…”

Insights of the ultralow wear and low friction of carbon fiber reinforced PTFE in inert trace trace moisture environment

“…Tribotests were conducted in an environmentally controlled 3-pin-on-disc tribometer described in detail in a previous publication [30]. The climate system has recently been upgraded with improved sealing of the climate chamber and the installation of a moisture trap in the gas re-circulation loop.…”

“…The climate system has recently been upgraded with improved sealing of the climate chamber and the installation of a moisture trap in the gas re-circulation loop. Thus, lower impurity levels of moisture and oxygen can now be achieved, in comparison to [30]. For all tribotests, the climate chamber was purged and over-lled with nitrogen to a relative pressure of 0.4 bar.…”

OpenHumidistat: Humidity-controlled experiments for everyone

“…Humidity control is essential for a plethora of biological, chemical, and physical experiments [1], some of which simply require a stable, constant humidity, while in others the humidity might be an experimental variable which is varied. In either case, careful humidity control is necessary.…”