An engineering approach to dry friction behaviour of numerous engineering plastics with respect to the mechanical properties

Abstract

The effect of friction on the wear of engineering polymers is a complex and intricate consequence of the micro-and macroscopic interactions of surfaces moving against one another. Friction and the resulting wear are not material properties of plastics; therefore, they cannot be reduced to tabular data of material characteristics that can be found in relevant manuals. Determining friction and the resulting wear involves more complex examination because they are characteristics of a frictional contact system where the effects of the entire system are manifest. Precise knowledge of system conditions is essential to evaluate the friction and resulting wear [1]. These materials have system-dependent tribological behaviour; thus, trends can be defined at a given condition, and the materials can be compared. The system approach is well-known from the literature [2, 199 An engineering approach to dry friction behaviour of numerous engineering plastics with respect to the mechanical properties G. Kalácska Abstract. Twenty-one different commercial-grade engineering polymers, including virgin and composite types, were selected for testing, based on mechanical engineering practices. Three groups were formed according to typical applications: 1) Sliding machine element materials; 2) Mechanically load-carrying machine element materials that are often subjected to friction and wear effects; and 3) Additional two amorphous materials used as chemically resistant materials that have rare sliding load properties. The friction running-in state was tested using a dynamic pin-on-plate test rig. During steady-state friction tests, two pv regimes (0.8 and 2 MPa"ms -1 ) were analysed by a pin-on-disc test system. Based on the measured forces on ground structural steel, surface friction coefficients were calculated and analysed with respect to the mechanical effects of friction. The friction results were evaluated by the measured mechanical properties: yield stress, Shore D hardness, Young's modulus and elongation at the break. The three material groups exhibited different trends in friction with respect to changing mechanical properties. Linear (with varying positive and negative slopes), logarithmic and exponential relationships were observed, and occasionally there were no effects observed. At steady-state friction, the elongation at the break had less effect on the friction coefficients. The dynamic sliding model, which correlates better to real machine element applications, showed that increasing hardness and yield stress decreases friction. During steady-state friction, an increase in pv regime often changed the sign of the linear relationship between the material property and the friction, which agrees with the frictional theory of polymer/steel sliding pairs.

Rotational Cone Tribometer (RCT) for Approaching the Tribological Behavior of Hard and Soft Sealing Materials Under Dynamic Line Contact

“…Friction coefficient of POM ring sample as a function of sliding speed measured using the rotational cone tribometer is compared against those measured using various standard tribometers such as Pin‐on‐disk tribometer, ball‐on‐pyramid, ring‐on‐face (Figure ). For the purpose of comparison of the friction coefficients, the considered measurements were performed at room temperature and at a contact pressure comparable to that in rotational cone tribometer of about 2 MPa.…”

Global Approach of Tribomechanical Development of Hybrid Aluminium Matrix Syntactic Foams

“…The possible correlation between the mechanical and tribological properties often helps to predict the behaviour of different materials under a given condition [42].…”

“…Some tribological data is available for hybrid (hollow sphere + particle) reinforced AMSFs too [39], but only a few for hollow sphere + hollow sphere reinforced hybrid AMSFs [40,41], with larger reinforcement size (Ø> 1mm). Also no literature was found in which correlations between mechanical and tribological properties of AMSFs were considered, however in tribology it is an essential knowledge in many aspects [42].…”

Thermal conductivity of plasma modified polyethylene terephthalate and polyamide-6 layers

“…Their use can reduce the maintenance costs, too. Several studies on the tribological behaviour of the most common engineering plastics [polyamides (PA) [3], polyoxymethylene (POM) [4] and polyethylene terephtalate with polytetrafluoroethylene (PET/ PTFE) [5] in contact with steel have been published and compared by, e.g., Tanaka [6], Evans and Senior [7], Guezmil et al [8] and Kalácska [1]. Polymers as viscoelastic materials are greatly sensitive to the heat of friction.…”

“…There is an increasing tendency to replace metal components by various kinds of engineering plastics [1]. The application of polymers for sliding parts is beneficial due to their corrosion resistance, damping characteristics and self-lubricating abilities [2].…”