Rolling Resistance Research Articles

Investigating the Influence of Heat-Insulated Wheelhouses on Truck Tyre Temperature and Rolling Resistance

Due to legislations introduced to prevent global warming, vehicle manufacturers must find new ways to reduce CO2 emissions. This paper explores a way to reduce rolling resistance by heat-insulating and covering a truck’s wheelhouse. Truck tyre rolling resistance was measured at +5 °C ambient temperature for consecutive speed steps in a climate wind chamber with and without heat insulation. The study showed that by encapsulating and insulating the wheelhouse, already generated strain-induced heat could be kept in the tyre, consequently leading to reduced rolling resistance. The tyre shoulder temperature was monitored during the experiments along with the tyre pressure. When the wheelhouses were encapsulated, a significant reduction in rolling resistance and an increase in tyre pressure and temperature were measured at all evaluated speed levels.

Rolling Resistance Evaluation of Pavements Using Embedded Transducers on a Semi-Trailer Suspension

Road agency initiatives to reduce traffic-related greenhouse gas emissions are limited by the inability of current experimental methods to assess pavement impacts on vehicle energy consumption. This study addresses this by examining the rolling resistance of a semi-trailer suspension under highway conditions using a precise measurement system with embedded transducers. Data were collected over 174 km of highway, covering various pavement types under mild summer conditions. The analysis revealed notable differences in rolling resistance due to pavement characteristics, with more pronounced variations observed within pavement types than between them. For instance, geographically consecutive jointed rigid pavements showed a 34% variation in rolling resistance, likely correlated with harmonic excitations generated by slab presence, while flexible pavements exhibited up to a 21% variation under similar tire operating conditions. Composite pavements generally performed the worst, possibly due to interactions between bituminous materials and older cement-based foundations. The study also highlighted the critical role of tire operating conditions, showing a decrease of 0.09 kg/tonne in rolling resistance for every 1 °C increase in temperature. This research shows that precisely measuring the rolling resistance (±0.1 kg/tonne) in situ for heavy vehicles is feasible and underscores the need for additional data in diverse weather scenarios to better align laboratory results with on-road realities.

Prediction Model of Pipeline Push Resistance in Tunnels

The installation of pipes in tunnel construction using the external welding method requires the assistance of a pipe pusher and roller support to push the welded pipe into the tunnel. Accurate determination of pipeline push resistance and the selection of an appropriate pipe pusher model are crucial factors for successful construction. Currently, there is no effective method available for predicting push resistance, which may result in inaccurate estimation and inadequate thrust provided by the selected pipe pusher. Therefore, this study aims to establish a reliable formula for calculating push resistance through theoretical analysis and numerical simulation. Additionally, we investigate the rolling resistance coefficient between the pipe and roller wheel to develop a corresponding prediction formula. Finally, a test platform is set up to validate our proposed formula for estimating push resistance. The results demonstrate that there is approximately a 5% error between the calculated values and the test values, confirming that this method effectively predicts pipeline push resistance.

Efficient and Accurate Calibration of Discrete Element Method Parameters for Black Beans

Discrete element parameters of the black bean (BLB) are key to developing high-performance BLB machineries (e.g., seeders and shellers), which are still lacking in previous literature. In this study, the effects of the radius and lifting speed of cylinder-in-cylinder lifting method (CLM) simulations were investigated to efficiently and accurately obtain the repose angle. Discrete element method (DEM) parameters of the BLB were determined by combining the Plackett–Burman Design test, the steepest ascent design test, and the central composite design test. The results show that the measurement moment (i.e., 12 s) of repose angles should be determined when kinetic energy reaches the minimal threshold (1 × 10−6 J) to efficiently and accurately obtain repose angles; too early or too late a measurement can result in inaccurate repose angles or excessive computation time of the computer, respectively. The lifting speed and cylinder radius affected the lateral displacements of BLBs and came at the cost of higher computation time and memory usage. A lifting speed of 0.015 m s−1 and a radius of 40 mm of the cylinder were determined in CLM simulations. The static friction coefficient and rolling friction coefficient between BLBs significantly affected the repose angles. A static friction coefficient of 0.202 and rolling friction coefficient of 0.0104 between BLBs were obtained based on the optimization results. A low relative error (0.74%) and insignificant difference (p > 0.05) between the simulated and measured repose angles were found. The suggested method can be potentially used to calibrate the DEM parameters of BLBs with good accuracy. The results from this study can provide implications for investigating interactions of BLBs and various BLB processing machines and for the efficient and accurate determination of DEM parameters of crop grains.

Numerical and experimental study of particle shape effect on pile properties based on a 3D sinter model

The research described in this paper studies the effect of particle shape on pile properties such as pile shape, repose angle and porosity through Discrete Element Method (DEM) simulation and small-scale experiments. An actual sinter particle was used as a template, with a three-dimensional (3D) model of it reconstructed from two-dimensional images using the close-range photogrammetry method. This 3D model was then employed to produce 3D-printed particles for experiments and to generate multi-sphere particles for simulations. The key contact parameters of the 3D-printed particles were obtained from experimental measurements and used for pile formation simulations. The results demonstrate that particle shape has a significant impact on the formation and structure of piles. In simulations with eliminated rolling friction coefficient, the repose angle changes significantly initially when the particles transition from sphere to more complex shapes. At growing shape complexity the effect on the pile structures eventually becomes negligible. In bulk-calibrated simulations, porosity exhibits a non-monotonic trend with changes in sphericity. The porosity of particles with sphericity most similar to sinter shows the greatest consistency with experimental porosity. The findings suggest that particle shape has a critical influence on the properties of piles, and the complexity of particle shape has a profound impact on particle behaviour.

Designing high-performance green tire treads by reinforcing the styrene-butadiene rubber/silica interface with chain difunctionalization

For green tires, monofunctionalization of rubber has been extensively studied to enhance the interface between rubber and silica. However, the effect of chain difunctionalization has not been reported. In this work, the difunctionalized styrene-butadiene rubber (SBR-DF) was first prepared by grafting small molecules with different functional groups (3-mercaptopropionic acid, 3-mercaptoethanol, and mercaptosilane) to end-group functionalized SBR through thiol-ene click reaction. Then, the molecular dynamics simulation was adopted to calculate the interaction energy between SBR-DF and silica. The results showed that the chain difunctionalization can significantly increase the interfacial interaction energy between them, which was further validated by using RPA and SEM. Moreover, the introduced siloxane groups in the rubber chain can greatly improve the interfacial interaction energy by more than 20 %, which can achieve the uniform dispersion of silica. As a result, the SBR-DF/Silica composites showed the excellent dynamic mechanical properties, such as high wet slip resistance (21 % increase), low rolling resistance (23 % reduction) and high wear resistance (20 % reduction). As a result, the energy consumption of SBR-DF/Silica composites was reduced, which endowed green tires with excellent safety. In summary, this work provides a new and effective strategy for manufacturing the energy-saving, green and safe design of “green tires”.

Simulation and Experimental Study on Indentation Rolling Resistance of a Belt Conveyor

In this paper, in order to reduce the indentation rolling resistance of a belt conveyor and improve its operation efficiency, the indentation rolling resistance of a belt conveyor is studied. Firstly, the theoretical calculation of the indentation rolling resistance caused by the contact between a conveyor belt and an idler is studied. Additionally, the expression of the indentation rolling resistance including the multi-element Maxwell relaxation modulus is simplified and deduced using the assumption of small deformation, and the steps of iterative calculation of the indentation rolling resistance through setting the initial values are designed. Then, the multi-component Maxwell relaxation modulus function of the conveyor belt tested in the previous work of the authors is substituted into COMSOL 5.6 finite element software, and the stress distribution caused by the contact between the conveyor belt and the idler under different working conditions is analyzed. Also, a series of measures to reduce the indentation rolling resistance are found through the laws presented by the simulation results. Finally, the experimental study of the indentation rolling resistance is carried out using the indentation rolling resistance testing device from our research group. By comparing the experimental results for the indentation rolling resistance under different working conditions with the theoretical calculation results for the indentation rolling resistance, it was found that the relative error was less than 13%, which proved the feasibility of the indentation rolling resistance and relaxation modulus testing method, as well as the theoretical calculation method for indentation rolling resistance.

Determination of Friction Characteristics of Corn Ears at Varying Factors in Mechanical Peeling

ABSTRACTIn view of the low bract removal and high corn ear damage in the operation of the current peeling device, this work aimed to accurately measure the coefficients of friction (COFs) involved between peeling rollers and corn ears during the corn peeling. Consequently, the movement state of corn ear in a peeling device and the friction behavior involved were analyzed, and the mechanical model was established. Friction tests were conducted by using the modified tilting table, the modified direct shear apparatus, and the self‐built rolling friction apparatus. The value range and change rule of the COFs between corn ears and peeling rollers were obtained. Linear regression models were described for the COFs depending on moisture content. The results show that the coefficient of static friction (COSF) was 0.391–1.396, the coefficient of sliding friction (CODF) was 0.398–1.318, and the coefficient of rolling friction (CORF) was 0.119–0.377. All COFs were positively correlated with moisture content. Besides, the COFs of two rubber rollers were significantly larger than that of the steel roller. Among the two rubber rollers, the COFs were higher between the fish scale rubber roller and bare corn ears and were lower between the fish scale rubber roller and corn ears with bracts. This meant that the fish scale rubber roller was more likely to cause seed damage under the same conditions. Knowledge concerning these coefficients is believed to provide data support for the improvement and optimization of corn peeling devices.

Distributed optimal control design with the feed-forward compensator for high-speed train

The distributed optimal design of high-speed train movement is systematically investigated in this article. A distributed optimal control law is proposed, addressing the train consist of cars coupled by spring buffers, and is affected by aerodynamic drag and rolling resistance. A new distributed controller is proposed to decouple the train model by fully removing the in-train force, which greatly simplifies the complexity of calculation. Then the pending problem is redescribed to the control of cars with different mass. Grounded on the Lyapunov stability theory and optimal control theory, distributed optimal control law is proposed in line with guaranteed cost function, which enables faster updates of the real-time status of each car and adaptive vehicle mass. It ensures consistency in the tracking process of each car of the train, and further reduces the in-train force among cars. To eliminate the speed overshoot which results from the influence of acceleration change during train operation, we weigh in with the feed-forward compensator to assure the train’s good acceleration performance. Ultimately, numerical simulations results are obtained to demonstrate convincingly the significance of our proposed control law.

Evaluation of static and rolling friction coefficients of granulated sugar using the discrete element method in a rolling mode rotating drum

PurposeThis research investigates the behavior of granulated sugar particles of different sizes in a rotating drum at varying speeds, using the discrete element method (DEM) as a mathematical modeling approach.Design/methodology/approachThe study conducted a data scan to determine both static and rolling friction coefficients. Based on benchmark studies, the Hertz–Mindlin contact model with rolling history elastic-plastic spring-dashpot (EPSD) and CDT (directional constant torque) models were employed to simulate the behavior of granulated sugar particles in a rotating drum under varying speeds.FindingsIn this research, the static and rolling friction coefficients presented the best values for granulated sugar near 0.60 and 1.5, respectively, applying the CDT model. The method demonstrated great accuracy in replicating experimental data.Originality/valueThis study enables comprehension of the behavior of the particles and particle system in a rotating drum at different speeds. The method may develop models that characterize and predict the main effects of particle systems to reduce project time and expense, especially in the food industry.

Friction in Oil-Lubricated Rolling–Sliding Contacts with Technical and High-Performance Thermoplastics

Thermoplastics show great potential due to their lightweight design, low-noise operation, and cost-effective manufacturing. Oil lubrication allows for their usage in high-power-transmission applications, such as gears. The current design guidelines for thermoplastic gears lack reliable estimates for the coefficient of friction of oil-lubricated rolling–sliding contacts. This work characterizes the friction of elastohydrodynamic rolling–sliding contacts with technical and high-performance thermoplastics with oil lubrication. The influence of polyoxymethylene (POM), polyamide 46 (PA46), polyamide 12 (PA12), and polyetheretherketone (PEEK), as well as mineral oil (MIN), polyalphaolefin (PAO), and water-containing polyalkylene glycol (PAGW), was studied. Experiments were carried out on a ball-on-disk tribometer, considering different loads, speeds, temperatures, and surface roughness. The results show that, for fluid film lubrication, there is very low friction in the superlubricity regime, with a coefficient of friction lower than 0.01. Both sliding and rolling friction account for a significant portion of the total friction, depending on the contact configuration and operating conditions. In the mixed to boundary lubrication regime, the sliding friction depends on the thermoplastic and rises sharply, thus increasing the total friction.

Modeling of Multibody Lubrication Dynamics in Cylindrical Roller Bearings

As a typical multibody system, rolling bearing consists of several lubricated frictional pairs which transmit motions and forces among components. In this paper, a multibody lubrication dynamics (MLD) model of cylindrical roller bearings (CRBs) is developed by coupling the bearings dynamics sub-model and several lubrication sub-models of each frictional pairs in real-time. The lubrication sub-models are discretized by using finite difference and solved by numerical iteration methods of Gauss-Seidel with line relaxation and discrete convolution-fast Fourier transform (DC-FFT) technique. What’s more, a parallel algorithm is also designed to enhance the calculation efficiency. Its results are validated by the experimental results in literature, and further compared by the results from other dynamics models. It is revealed that the film formation changes not only friction but also geometrical constraints and pressure distribution, which may introduce additional load inside bearing and increase rolling friction under high-speed conditions. As the dynamic oil film stiffness and damper are took into account by MLD, the cage has a lower whirl frequency and forces. The curve-fitting formulas of EHL film thickness are overestimates the thickness value, and thus change the load distribution and friction between roller and raceway.

Open-structured silica network based on silane-terminated telechelic polybutadiene for electric vehicle tires

The shift towards electric vehicles (EVs) is essential for a sustainable future. Tire manufacturers face challenges including accommodating extra weight, managing instant torque, reducing noise, and improving driving range. Meeting these demands involves substantially reducing the rolling resistance of tire tread composites while simultaneously enhancing their mechanical stiffness and wear resistance. To overcome these issues, an open-structured silica network based on silane-terminated liquid-like telechelic polybutadienes was introduced into rubber composites. This unique network consists of silica aggregates that are chemically bound together, but exhibit physical separation, enabling rubber chains to permeate. The infiltrated polymer chains were tightly constrained by the network, resulting in a notable increase in the crosslink density and mechanical strength of the composite. Furthermore, the tan δ values at 60 °C showed a notable decrease as a result of diminished interparticle friction caused by isolated silica structures and reduced mobility of polymer chains within the network. These findings provide the tire industry with crucial insights for the development of energy-efficient and durable tires for EVs. By addressing these specific requirements of EVs, our study paves the way for more sustainable tires and contributes to the broader adoption of EVs in a sustainable future.

Methodology for Study of Rockfalls in Urban Areas – Computer Modeling and Mitigation in Algodonales, Spain

Rockfalls in urban areas can cause significant damage. Without direct observation, it is difficult to reconstruct the specific details of an event. The study of rockfalls requires analyses of the source areas, slope parameters, blocks characteristics (size, shape, and mass), and the likely movements of independent blocks along their trajectories (free-falling, rolling, sliding, and rebounding). This article will propose a feasible methodology for the study of rockfalls based on identifiable parameters, conditioning factors (geology, geomorphology, geomechanical, hydrogeology, climate, and biology), and triggering factors (climate and dynamic loads). This article proposes the use of modeling programs to facilitate rockfall research and data management. The study of conditioning factors allows researchers to state several coefficients (restitution, surface roughness, rolling resistance, and friction) that one inputs into a modeling program, allowing researchers to obtain the representative results that are needed to design effective remedial measures. The methodology has been successfully applied to the urban area of Algodonales (Province of Cádiz, Spain).

Integration soil contact model – A flexible pressure-sinkage method for simulating low speed vehicles with wheels and tracks

An integration soil contact model and a modular terramechanics simulator VieteriSim for vehicles running on wheels and tracks were developed. The presented computational method extends the soil contact model by introducing a user defined pressure-sinkage relationship according to a theoretical function or an experimental data set, a numerical integration of pressure over a contact area with a desired resolution and vector based rolling resistance coefficient calculation. The convergence of the model and the capability of the computational method are demonstrated by simulating a cut-to-length timber forwarder running on a soft terrain with and without bogie tracks.

RHEOLOGICAL BEHAVIOR OF ALUMINUM SOAP: A NEW PROSPECT FOR TREAD RUBBER APPLICATION

ABSTRACT Aluminum soaps are notable for their enormous power of thickening many organic hydrocarbon solvents. We investigated the rheological behavior of aluminum dioleate, an aluminum soap, in squalane. Intriguingly, its linear rheological properties resembled those of entangled polymer melts, whereas its nonlinear behavior exhibited similarities to the Payne effect observed in particle-suspended systems. Using high-resolution microscopy, we discovered that its thickening power arises from the formation of spherical nanoparticles from the aluminum soap molecules that then aggregate into highly fractal networks in the dispersion medium. Remarkably, this nanoparticle formation occurs not only in small-molecule organic media but also in long-chain macromolecular rubber matrices, such as SBR. This discovery suggests that the aluminum soap may reinforce the polymer matrices and offer some rheological benefits in resulting rubber compounds. We then incorporated 10 phr of the aluminum soap into a silica-filled tread rubber formulation. The results revealed significant enhancements in tensile strength, accompanied by reduced rolling resistance. These promising outcomes highlight the practical application potential of aluminum soaps in tread formulations.

Bed strength in sheared beds of mono- and bi-disperse particles: Dependence on geometrical and mechanical properties of constituent particles

Temporary plugging zones are low-permeability fracture-scale plugs ‘assembled’ in situ by injecting polymer particles into petroleum reservoirs. We applied the rolling resistance linear model to simulate the shear strength of a rectangular packed bed, our model for a temporary plugging zone, comprising either uniform-sized particles or a binary mixture of larger bridging particles and smaller filling particles. Simulation results show that the strength of uniform beds increases with the size, the aspect ratio, the friction coefficient, and the Young’s modulus of the particles. The strength of binary packed beds first increased and then decreased as the fractional volume of the domain occupied by filling particles increased. Maximum strength was achieved when bridging particles have uniform Young’s modulus and aspect ratio but a range of friction coefficients, and their friction coefficient, Young’s modulus and aspect ratio are 21%, 17% and 18% larger than those of filling particles.

A study on the temperature rise characteristics of high-speed ball bearings under starvation lubrication

PurposeThis paper aims to study the problem of starvation lubrication of high-speed ball bearings due to temperature rise during operation and to avoid thermal failure of bearing lubrication.Design/methodology/approachUnder the quasi-statics model of grease lubrication, both the oil film dragging force and the rolling friction between the balls and raceways collectively counteract the gyroscopic torque. Initially, the static model for grease lubrication is solved, followed by calculating the generated heat using the local heat generation method and ultimately the multinodal thermal network model is solved, and the solved results of the quasi-statics are updated by the temperatures of the grease nodes based on the relationship of the grease temperature and viscosity, as well as the relationship of the viscosity and the film thickness.FindingsBy comparing the numerical calculation results of bearings under different working conditions, the influence of starvation lubrication on the oil film thickness, oil film drag force and rolling friction of bearings is discussed, and it is found that the numerical calculation results of the outer ring temperature of bearings under the starvation lubrication due to the consideration of temperature rise are closer to the experimental values.Originality/valueThis study reveals the dynamic characteristics of bearings under starvation lubrication, which is more practical and engineering guiding significance for the design of bearings, and introduces a new method and basis for the calculation of temperature rise of rolling bearings.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2024-0208/

Influence of high cis-1,4-liquid polydienes on properties of carbon-black filled composites

High cis-1,4 liquid polybutadiene (cLBR) and polyisoprene (cLIR) with narrow molecular weight distribution were prepared by the chain-transfer coordination polymerization. The effects of cLBR and cLIR on the physical and dynamic mechanical properties of carbon-black filled composites containing single polybutadiene (PBR) or a blend of PBR/polyisoprene (PIR), were investigated. The results showed that cLBR and cLIR effectively ameliorated filler dispersion compared with the treated distillate aromatic extract (TDAE) oil. The wet skid resistance and rolling resistance of vulcanized PBR/PIR composites plasticized with 5 phr cis-1,4 liquid rubbers were significantly improved. Therefore, a new type of plasticizers cLBR and cLIR that are environmental benign and highly compatible with matrix rubbers, has been discovered to replace the conventional TDAE oil used in fabricating the “green” tyres.

Study of Styrene Butadiene Rubber Reinforced by Polybutadiene Liquid Rubber-Modified Silica.

The dispersion of silica in rubber systems and its interaction with rubber are two key factors in the preparation of rubber composites with excellent properties. In view of this, silica modified with terminal isocyanate-based polybutadiene liquid rubber (ITPB) is used to improve the dispersion effect of silica in rubber and enhance its interaction with the rubber matrix to improve the rubber's performance. The impact of different modification conditions on the dispersion of silica and the properties of modified silica-filled rubber composites were studied by changing the amount of ITPB and the modification method of silica, including blending and chemical grafting. The experimental results show that ITPB is successfully grafted onto silica, and the use of modified silica improves the cross-linking density of rubber, promotes the rate of rubber vulcanization, and overcomes the shortcomings of the delayed vulcanization of silica itself. When the ratio of ITPB liquid rubber to silica equals 1:20, the comprehensive performance of rubber is the best, the ITPB-modified silica has a better dispersion effect in rubber, and the rolling resistance is slightly improved, with tensile strength reaching 12.6 MPa. The material demonstrates excellent overall performance and holds promise for applications in the rail, automotive, and electrical fields.