Frictional Temperature Rise Research Articles

Effect of the infill percentage of 3D printed Polyetheretherketone under the dry sliding condition

Sliding bearings made of advanced polymers like Polyetheretherketone (PEEK) are preferred for medium and heavy-duty applications. The high-temperature additive manufacturing process permits the efficient fabrication of lighter porous parts using high-cost materials like PEEK. Customised geometries and surface features are easily achievable using an additive manufacturing process and facilitate design for the required performance. The 3D-print parameters employed affect the surface characteristics and are investigated. The variation in infill porosity is found to affect the crystallinity, hardness, modulus, and surface roughness of the printed samples. The friction coefficient variation, wear resistance, and temperature rise in the 3D-printed PEEK samples are studied when slid against steel discs under dry sliding conditions. The material transfer between surfaces varies based on the sample's surface properties and porosity, significantly affecting friction and wear behaviour. Accumulation and strong adhesion of wear debris in the groves of PEEK samples contribute to improved wear resistance. The temperature rise in the polymer sample also depends on the infill porosity, and a reduced temperature rise is observed in porous samples, which will improve the life when used in bearings.

Study on the dynamic evolution of friction and wear of polyurethane material for pipeline inspection gauge

The dynamic evolution in friction and wear can lead to interface failure and induce vibrations in pipeline inspection gauge. The friction behavior between polyurethane and X70 steel was evaluated with annular face contact under 0.042 to 0.07 MPa. The temperature increase was recorded using infrared cameras. Dynamic simulations of frictional heat and stress-strain were conducted using Abaqus software. The results indicate that in the initial stages, abrasive wear, stress (1.5 MPa), and frictional temperature rise (65 °C) of PU were observed in the inner-ring region at 0.056 MPa. The surface roughness (3.394 μm) of the PU became comparable to that of the steel ring (3.768 μm) due to abrasive wear. In the later stages, a higher frictional temperature (80 °C) and increased stress (3.8 MPa) were observed in the outer ring. Concurrently, Schallamach waves and ridge-like stripes indicative of stick-slip behavior emerged in the outer ring. The viscoelastic hysteresis effect is the fundamental cause of the dynamic evolution of the friction coefficient and wear. Frictional heat exacerbates the evolution of stick-slip behavior and increases fluctuations in the friction coefficient. The findings of this research can be utilized to analyze the causes of interface failure and vibration in pipeline inspection gauge.

Research on Calculation and Optimization Methods for Tooth Flash Temperature and Meshing Power Loss of the Gear System in Drum Shearer

The operating conditions of the drum shearer are very complex, and its ranging arm gear system often suffers from gear scuffing and wear. Gear scuffing is caused by the adhesive wear, which is due to the instantaneous friction and flash temperature of the tooth surface, and the gear meshing power loss is also caused by tooth surface friction. In order to resist tooth scuffing and improve meshing efficiency of the transmission system, an improved semi-analytical tooth surface flash temperature calculation method was used. The tooth flash temperature status under various working conditions were analyzed in detail. Based on the mechanical model of the shearer drum picks, the load condition of the drum was analyzed. Under these load and boundary conditions, the misalignments of each gear pair in the ranging arm were calculated. The tooth surface load distribution was calculated under the gear misalignments, and then the theoretical tooth surface flash temperature and meshing power loss were determined. Next, the tooth micro-geometry was modified to reduce flash temperature and meshing power loss. The flash temperature distribution pattern of the optimized tooth surface was studied under various working conditions, and the meshing power loss was also obtained. Finally, experiments were conducted to verify the effects of the optimized tooth surface on the friction temperature rise and the effectiveness of the modification method. Tooth surface optimization aimed at reducing tooth surface flash temperature can also effectively reduce meshing power loss, which has a significant effect on gear anti-scuffing and energy saving.

Experimental study on operating characteristics of rotor-bearing system lubricated by gallium-based liquid metal

PurposeThe purpose of this paper is to explore the operating characteristics of gallium-based liquid metals (GLMs) by directly adding them as lubricants in real mechanical equipment.Design/methodology/approachThis paper conducts an analysis of the rotor-bearing system under GLM lubrication using a constructed test rig, focusing on vibration signals, surface characteristics of the friction pair, contact resistance and temperature rise features.FindingsThe study reveals that GLM can effectively improve the lubrication condition of the tribo-pair, leading to a more stable vibration signal in the system. Surface analysis demonstrates that GLM can protect the sample surface from wear, and phase separation occurs during the experimental process. Test results of contact resistance indicate that, in addition to enhancing the interfacial conductivity, GLM also generates a fluid dynamic pressure effect. The high thermal conductivity and anti-wear effects of GLM can reduce the temperature rise of the tribo-pair, but precautions should be taken to prevent oxidation and the loss of its fluidity.Originality/valueThe overall operating characteristics of the rotor-bearing system under GLM lubrication were investigated to provide new ideas for the lubrication of the rotor-bearing system.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2024-0067/

Friction-induced temperature rise at energetic β-HMX crystal interfaces: Part II. Simulation of HMX rough surface under dry friction conditions

In this study, the frictional temperature rise of HMX/HMX is investigated with a rough surface sliding on a flat surface by finite element method. The simulation model on the frictional temperature on HMX surface is validated by the in-situ temperature monitoring at moderate friction conditions by tribological experiments and friction-induced ignition of HMX at extreme conditions by friction sensitivity tests. Simulation results reveal that the significance order of frictional parameter that determine the maximum temperature on the asperity of HMX is: friction coefficient > sliding speed > contact pressure. Surface roughness of HMX surface can also affect the frictional temperature rise. Furthermore, a frictional power density of ∼10.8 W/mm2 is determined as the critical security boundary of the friction system when the critical temperature is set to 220 ℃. These findings can provide deep insights into the microscale hot-spot formation and frictional safety mechanisms of explosives.

Effect of operating conditions and surface roughness on grease lubrication efficiency

The aim of this paper is to investigate the effect of operating parameters (load and rotational speed) and arithmetic mean deviation (Ra) roughness value on temperature rise and tribological behavior of greased point contact under heavy load. The 3-factor, 4-level orthogonal friction experiments are designed and carried out. The moving point heat source integration method is applied to calculate the transient temperature rise of interfaces. The results show that the case with load 1900 N, rotational speed 260 rpm and Ra 0.4 μm has the highest friction coefficient and temperature rise. The grease fails and layered spalling and oxidative wear occur on the wear scar. Four second-order regression models are established to predict friction coefficient and the maximum temperature rise under different load, rotational speed and surface roughness. And the determination coefficients R2 of them are higher than 97 %. The models are helpful to determine if the working conditions fall within effective lubrication range and avoid severe damage.

Atomic-Scale Insights Into Graphene/Fullerene Tribological Mechanisms and Machine Learning Prediction of Properties

Abstract Graphene/fullerene carbon–based nanoparticles exhibit excellent tribological properties in solid–liquid two-phase lubrication systems. However, the tribological mechanism still lacks profound insights into dynamic friction processes at the atomic scale. In this paper, the friction reduction and anti-wear mechanism of graphene/fullerene nanoparticles and the synergistic lubrication effect of the binary additive system were investigated by molecular dynamics simulations and tribological experiments. The friction performance was predicted based on six machine learning algorithms. The results indicated that in fluid lubrication, graphene promoted “liquid–liquid” interlayer sliding, whereas fullerene facilitated “solid–liquid” interface sliding, resulting in a decrease or increase in friction force. Under boundary lubrication, graphene/fullerene nanoparticles were adsorbed and anchored at the metal interface to form a physical protective film, which improved the bearing capacity of the lubricating oil film, transformed the direct contact between asperities into interlayer sliding of graphene and roll–slide polishing, filling, and repairing of fullerene, thus improving the frictional wear of the lubrication system as well as the friction temperature rise and stress concentration of the asperities. Furthermore, six machine learning algorithms showed low error and high precision, and the coefficient of determination was greater than 0.9, indicating that all models had good prediction and generalization capabilities, fully demonstrating the feasibility of combining molecular simulation and machine learning applications in the field of tribology.

BPANN modified constitutive descriptions for flow behavior and softening mechanism in the α+β phase region of Ti-55511 alloy with equiaxed microstructure

The deformation behavior of Ti-55511 alloy was investigated by hot compression tests conducted at deformation temperatures of 993∼1113 K and strain rates of 0.001–1 s−1. To eliminate the effects of friction and adiabatic temperature rise on the flow stresses, the flow curves were corrected. Subsequently, a strain compensated Arrhenius (SCA) model was developed and further modified using the back propagation artificial neural network (BPANN) method. The modified model exhibits significant improvements compared to the SCA model. The average absolute relative error (AARE) decreases from 4.895 % to 0.756 %, while the relative error (δ) range decreases from −14.75 %–17.99 % to −4.78 %–8.01 %. Moreover, cross-validation also confirms the modified model has higher generalization ability and prediction accuracy than the SCA model. Microstructural characterization reveals dynamic recrystallization (DRX) of the α phase and dynamic recovery (DRV) of the β phase are the main mechanisms responsible for softening, and their volume fractions increase with decreasing strain rate and increasing deformation temperature. The equiaxed α phase undergoes elongation first, followed by gradual migration and transformation of grain boundaries. Finally, the β phase wedges into the α phase until the α phase separates. The continuous dynamic recrystallization (CDRX) of β phase accompanies its DRV, which is mainly characterised by progressive sub-grain rotation. The α grains aggregated by dislocations promote CDRX of the β phase.

Vacuum tribological properties in Cr-doped H-DLC self-lubricating radial spherical plain bearings

To improve the vacuum tribological properties of the self-lubricating radial spherical plain bearings (SSPBs), the multi-layered Cr-doped hydrogenated diamond-like carbon films (Cr-H-DLC) and non-doped H-DLC films as the lubricating materials were prepared on the inner ring with an outer spherical surface and the outer ring with an inner spherical surface by unbalanced magnetron sputtering. The microstructure, phase composition, tribological properties, and failure mechanism of Cr-H-DLC SSPBs and H-DLC SSPBs were investigated. The results showed that the microstructure of the outer and inner spherical surfaces for the two kinds of SSPBs was dense. The microgram indicated that the self-lubricating film thickness of the outer spherical surface was greater than that of the inner spherical surface. What is more, the Raman spectra showed that the self-lubricating coating on the outer spherical surface contains more graphite characteristics of sp2 hybrid bonds based on the value of ID/IG. According to the vacuum tribological test, the oscillating life of H-DLC SSPBs was higher than that of Cr-H-DLC SSPBs. Moreover, the change law of friction torque and friction temperature rise showed that the testing process of coated SSPBs could be divided into running-in, stable, and failure periods. Compared with the ID/IG values before and after the vacuum test, it could be inferred that the graphitization of the sp3 hybrid bond in the self-lubricating film on both spherical occurred. Based on the microscopic wear morphology, the failure mechanism of H-DLC SSPBs and Cr-H-DLC SSPBs were abrasive wear and fatigue wear. When the lubricating layer of the friction interface was worn, the metal substrate of the inner and outer rings would contact, resulting in adhesive wear.

The Tribological Behavior of Cast Iron by Laser Surface Texturing under Oil-Lubricated Initial Line Contact for Rotary Compressor

The tribological behaviors of cast iron by laser surface texturing were experimentally compared with the behavior of untextured by unidirectional rotary sliding friction and wear tests under oil-lubricated initial line contact. The friction coefficient and temperature rise were analyzed with the increasing load applied by block-on-ring tests. In addition, the wear loss and wear mechanism were also investigated through the surface topographies analysis. The results showed that the tribological improvement strongly depended on the contact form. For the oil-lubricated initial line contact in this work, the textured surface showed a better frictional advantage with a lower friction coefficient and lower temperature rise. The hydrodynamic effect enhanced the load-carrying capacity of the oil film and increased the film thickness. The friction coefficients were 11~64% lower than those on the untextured one. Meanwhile, the textured surface deteriorated the wear behavior due to the coupling effect between the micro-cutting effect of the texture edges and the material deformations of the counter surface. The material loss induced by abrasive wear and fatigue wear was the dominant wear mechanism. Namely, the laser surface texturing improved the friction properties but reduced the wear resistance.

Study on the rate of change of thread angle and thread distance considering the interference factor under before and after the dynamic vibration of the fastening system

Precision nuts are widely used in tool spindles and ball screws. Proper locking gives the bearing the right amount of pre-pressure so that the inner balls can roll steadily and inhibit friction and rapid temperature rise. If no pre-pressure is given to the bearing, it will cause the inner ball to slide irregularly and generate extremely high temperatures. In this paper, the precision nuts used are the flank locking precision locked nut and clasp locking precision locked nut for Taguchi method experiments. The control factors are nut type, Fitting clearance, and lubrication oil. Interference factors are surroundings temperature, assembly personnel, and torque wrench. The purpose is to obtain more suitable anti-loosening characteristics by the Taguchi method under the influence of interference factors and to check the thread angle and thread pitch before and after the experiment. The experimental results were analyzed form Taguchi method to find the combination of parameters with the maximum S/N and the variance analysis to obtain the significant factor. Finally, the regression equation of the loosening prevention characteristics was obtained by regression analysis, which shows that the optimized parameters effectively improve the loosening prevention characteristics and explore the interference factor on the loosening prevention characteristics of precision nuts.

Unified computational model of thermochemical erosion and mechanical wear in artillery barrel considering hydrodynamic friction

Erosion wear of the artillery barrel is divided into two primary categories: thermochemical erosion and mechanical wear. However, the majority of studies concerning this subject matter emphasize the former, and the latter has not been given enough consideration. To describe the coupling relationship of thermochemical erosion and mechanical wear, this article is inspired by the frictional behavior between the barrel and the projectile and proposes a material degradation model for thermochemical erosion considering frictional temperature rise. Under the coupling of the forced heat convection of high-temperature propellant gas and frictional heat, the friction state between the barrel and the projectile is changed from dry friction to hydrodynamic friction, resulting in a novel mechanical frictional wear model. Subsequently, numerical simulations of the thermochemical erosion and mechanical wear models are carried out. The results show that the erosion wear of the artillery barrel is divided into four regions along the axial direction: thermochemical erosion, thermochemical-mechanical erosion, transition, and mechanical wear regions. Four regions are concentrated in the interval of [0 mm, 500 mm], [500 mm, 1750 mm], [1750 mm, 4000 mm] and [4000 mm, 6800 mm], respectively.

Dynamics-Based Thermal Analysis of High-Speed Angular Contact Ball Bearings with Under-Race Lubrication

The paper mainly studied the temperature rise characteristics of under-race lubricated high-speed angular contact ball bearings under operational conditions from the perspective of dynamics. The steady-state calculation model of the bearing was established using a thermal network method in consideration of the influence factor of friction power consumption in bearing components based on a dynamic model. Following this, the steady-state change characteristics of the bearing were obtained by solving a thermal balance equation. Through this process, the influence laws of bearing rotation speed, oil supply, and environmental temperature on the friction temperature rise of the bearing were analyzed. Finally, the finite element analysis software ANSYS was employed to provide comparative verification. The results showed that the bearing temperature nonlinearly increased with the increase in inner ring rotation speed, and when it approached a certain critical value, the outer ring temperature exceeded the inner ring temperature. It had an obvious effect on controlling the temperature rise of the bearing inner ring by way of increasing the quantity and reducing the temperature of the lubricating oil supply. Comparative verification showed that the speed–temperature variation tendency from the dynamics-based thermal analysis well agrees with that of the finite element analysis.

An experimental measurement and numerical calculation method on friction temperature rise of sliding contact pairs - taking rail/wheel contact as an example

The analysis of rail/wheel sliding friction heat is a very important research field. The numerical simulation is often adopted to calculate the friction heat, and experimental method is relatively few. In this paper, an experimental machine is designed to simulate the rail/wheel sliding contact. At the same time, a rail/wheel contact wear model and a friction heat transfer model are established. The characteristics of temperature on rail/wheel sliding contact are analyzed by experimental test and numerical calculation. The research results show that the temperature rise of wheel and rail is quick in the initial sliding contact stage, then gradually slows down. The temperature of wheel is higher than that of rail at the same depth from the contact surface. In the initial sliding stage, the wheel temperature rises faster than the rail temperature, which is related to the size of contact surface and the concentration degree of friction heat. Moreover, the results of this paper show that the temperature values of the rail/wheel obtained through experimental test and numerical calculation are in good agreement. The experimental and numerical calculation methods used in this article can be adopted to analyze the contact problems of other sliding friction pairs.

Research on design and mechanical behavior of a new horizontal connection device of prefabricated shear wall

The mechanical properties of the connection joints/horizontal joints of the fabricated shear wall structure play a vital role in the fabricated structure. In order to improve the seismic performance of the fabricated shear wall structure, a new type of assembled shear wall horizontal connection device is designed and developed based on the principle of energy dissipation in this study. Two horizontal connection devices with different bolt number are designed and manufactured. The device comprises of high-strength bolts and Q345 steel. The dynamic mechanical behaviors are tested for the horizontal connection device under different sinusoidal loading frequencies. The influence laws of different bolt preload, loading frequencies and bolt numbers are explored on the mechanical properties of the device. The effect of friction temperature rise on the mechanical properties of the device is investigated. The experimental results indicate that the device can not only ensure the reliable connection of the structure, but also dissipate significant seismic energy by the internal friction of the device, so as to effectively reduce the seismic response of the structure and protect the main structure. Additionally, the energy dissipation capacity and secant stiffness of the device is proportional to the bolt preload, but the equivalent damping ratio is independent of the preload; the mechanical properties of the horizontal connection device hardly depend on the loading frequency; the increase of the bolt number can considerably enhance the energy dissipation of the device; Both the preload and loading frequency are important factors affecting the temperature rise of the device, but the temperature change has little effect on its mechanical behaviors.

Numerical simulations for artillery barrel temperature variation considering mechanical friction heat under continuous shots

Accurate modeling of artillery barrel temperature distribution is important to evaluate thermochemical-mechanical erosion and thermal shock. For such heat conduction problems, the previous works ignore frictional heat, especially for continuous shots. To end this, this paper proposes a numerical simulation approach for the temperature field on the inner barrel wall considering the frictional temperature rise. In the novel scheme, the frictional temperature between the barrel and the rotating band is derived from the frictional heat theory, and the heat transfer model is computed coupling the interior ballistic codes with the finite difference method. A close-formed solution for the continuous shots with an incomplete cooling barrel is provided, and followed by a finite element numerical simulation. The good agreement between the aforementioned two simulations demonstrates a good accuracy of the developed solution form. The results show that there is a temperature peak at the initial part of the rifling, which is much higher than the other parts, and far exceeds the critical phase transition temperature of the barrel steel material.

Research on the design and bearing characteristics of shipborne spiral elevator in specific small space

This work aims at the problem that the temperature rise, gluing or wear of the thread sliding friction pair under fast and heavy load make it difficult to estimate the service life of the equipment. Based on the numerical simulation method and the heat balance theory of the screw friction pair, the bearing characteristics of a self-designed shipborne multi-section free-telescopic screw elevator are studied. The results show that the stress of the thread tooth is mainly concentrated in the root area of the thread tooth, and the load of the thread is mainly concentrated in the first three threads of the meshing thread. When the friction coefficient is more than 0.3, the friction temperature rise will lead to gluing failure. Therefore, a good lubrication environment can effectively reduce the friction coefficient of the thread and reduce the screw contact surface gluing failure caused by the friction torque work heating.

Tribological behavior and mechanical properties of transmission wire rope bending over sheaves under different sliding conditions

Wear leads to performance degradation of the wire rope and seriously threatens its service reliability. This paper explored the tribological behavior of a transmission wire rope by a homemade rope-sheave sliding friction and wear test rig. Then, the strength and fatigue performance of the wire rope with different surface wear were investigated using customized test apparatuses. The results show that the friction coefficient (COF) is affected by the rope structure, contact angle and sliding velocity, which decreases from approximately 0.65 to 0.32 with increasing sliding velocity. The friction temperature rise is obviously influenced by the sliding velocity. It increases nonlinearly from approximately 51 °C to approximately 102 °C. The wear characteristics are mainly spalling, furrows and plastic deformation. The wear mechanisms are adhesive wear and abrasive wear. Additionally, with a decrease in sliding velocity, the breaking force decreases from approximately 48.7 kN–41.2 kN, and the bending fatigue life reduces nonlinearly. The maximum bending fatigue times decrease from approximately 9.9 k to 3.2 k. Furthermore, the surface wear accelerates the crack propagation rate of the service wire rope. The fracture mechanism of the wire rope is mainly ductile fracture under tensile loading and brittle fracture under fatigue loading.

The design method of the V-shaped groove piston ring

Abstract Aiming at the problems of large leakage and high friction heat generation of the piston ring under high pressure and high speed, based on the previous research on the V-shaped groove piston ring, the research on the design method of the V-shaped groove piston ring is carried out in depth. The numerical analysis is carried out focusing on the number of V-shaped grooves and the depth of the V-shaped grooves of the piston ring. The influence law is verified and analyzed by using a high-pressure and high-speed rotating test bench. The simulation and experimental results show that the leakage of 4 grooves and 8 grooves piston ring is reduced by 14.9 and 28.5%, and the temperature is reduced by 10.9 and 4.7%; When there are 8 V-shaped grooves on the piston ring, the leakage is reduced by 28.5 and 21.7%; when the V-shaped groove depth is 0.04 and 0.08 mm, the temperature is reduced by 4.1%. However, when the V-shaped groove depth is 0.12 mm, the leakage is increased by 2.7% compared with the traditional piston ring. Appropriate groove number and groove depth can realize the coordinated design of low leakage and low friction temperature rise.

Sliding Friction and Wear Characteristics of Wire Rope Contact with Sheave under Long-Distance Transmission Conditions.

Wire rope has different degrees of surface wear under long-distance transmission conditions, which leads to performance degradation and greatly threatens its safety and reliability in service. In this paper, friction and wear tests between the transmission wire rope and sheave under different sliding velocities (from 0.8 m/s to 1.6 m/s) were carried out using a homemade test rig. The material of the steel wires was low carbon steel, and pulley material was ASTM A36 steel plate. The sliding friction coefficient (COF), friction temperature rise, wear characteristic parameters and wear mechanisms of the wire rope were analyzed. Additionally, the effect of different wear on the fracture behavior of the wire rope was investigated by a breaking tensile test. The results show that the average COF in the relatively stable stage decreased from approximately 0.58 to 0.51 with the increase of sliding velocity. The temperature rise of the wire rope increased rapidly with an increase of sliding velocity, from approximately 52.7 °C to 116.2 °C. The maximum wear width was the smallest when the sliding velocity was 1.2 m/s (approximately 1.5 mm). The surface wear was characterized by spalling, furrowing and plastic deformation, which are strongly affected by the sliding velocity. The wear mechanisms of the wire rope were mainly adhesive wear and abrasive wear. Surface wear changes the fracture morphology of the wire rope and accelerates its fracture speed.