Low Rolling Resistance Research Articles

Characterization of the incorporation of a granular medium into elastomer matrices during mixing process

AbstractMixing of filler particles with elastomers is one of the most important steps in tire manufacturing process. Precipitated Silica (Si), as a filler, shows enhanced properties compared with carbon black when incorporated with an elastomer such as low rolling resistance, high wet grip performance, and high wear resistance. According to the standard rubber mixing process, the fragmentation of the filler particles in an elastomer during mixing must yield to breakage of particles to a size that enables homogenous mixing of the material. Hence, this experimental study is concerned with understanding the behavior of silica during its incorporation in the elastomer. Incorporation is done through shear forces present in the Internal Mixer. Different experimental methodologies are used to measure the particle size distribution. For free silica particles that have been fragmented but not incorporated, we use Laser granulometry. Silica embedded in elastomer is analyzed using X‐ray tomography. The results obtained suggest that free silica and silica embedded in elastomer follow erosion mechanism.

Preparation of silica/natural rubber masterbatch using solution compounding

There are increasing concerns about the global issues of carbon peak and carbon neutrality. The tire labeling laws about rolling resistance performance requirements have been revised accordingly. Energy-efficient “green tires,” with a lower rolling resistance, are becoming an important development direction for the tire industry. Herein, a method is proposed for preparing a silica/natural rubber (NR) masterbatch using solution compounding. The dispersion of silica in the rubber matrix was improved through the liquid-phase mixing process. Further, the loss factor (tanδ) of the rubber was reduced, ultimately reducing the rolling resistance of the material. Specifically, the modified silica slurry was prepared in cyclohexane with an interfacial modification technology, and the mixing between the silica and rubber molecular chains was completed in the organic phase. Favorable processing properties were confirmed using the Mooney viscosity test. Compared with the in situ modified silica/NR composites made using dry blending, the silica/NR composites made via solution compounding had better filler dispersion, better mechanical properties, lower tanδ and lower rolling resistance. Thus, the preparation of a silica/NR masterbatch using solution compounding provides a new procedure for the preparation of silica/NR compounds with excellent performance for “green tires.”

The self-assembly of sepiolite and silica fillers for advanced rubber materials: The role of collaborative filler network

Composite materials based on hybrid filler systems can be a promising approach to produce advanced rubber nanocomposites (NCs). Recently, the positive effect of the combined use of silica and sepiolite on NCs mechanical properties has been reported, compared to those of compounds reinforced with the same amount of the only silica filler. In this context, the present work aims at studying the possible synergistic self-assembly of nanosilica and sepiolite in the generation of a cooperative hybrid filler network in rubber-based NCs, in connection with material performance for tires application. In detail, the influence of the introduction of a secondary anisotropic filler in conjunction with isotropic nanosilica on their dispersion and interaction with the rubber matrix has been comprehensively investigated, in order to define the best formulation ensuring low rolling resistance and significant fuel saving.NCs, containing simultaneously silica and sepiolite, either pristine (Sep) or chemically modified (mSep) by an acid treatment, were prepared by combining latex compounding technique (LCT) and melt blending. Rheological and dynamic-mechanical analyses highlighted that the use of a double white filler, constituted by particles with different aspect ratio, affords a good balance between efficient reinforcement and low Payne effect.Tansmission electron microscope (TEM) analysis evidenced the formation, within the rubber matrix, of cooperative superstructures due to the self-assembly of sepiolite and silica nanoparticles containing occluded rubber, when the secondary filler is mSep. The peculiar characteristics of mSep, characterized by fibers shorter than Sep and higher surface silanol bonding sites, bring about significant interactions between mSep and silica, which promote self-assembly of the two fillers in a collaborative hybrid network, improving dynamic-mechanical performances.These results, even if related to sepiolite/silica NCs, demonstrate the effective role of the collaborative filler network, based on the hybrid double fillers, able to lend enhanced properties to rubber materials.

Self-repairable, recyclable and heat-resistant polyurethane for high-performance automobile tires

Tires are widely used in modern society and various industries. However, the formulations and manufacturing processes of traditional rubber are complex, and it is difficult to simultaneously meet requirements of low rolling resistance, high wet-skid resistance and wear resistance. Herein, we demonstrate a polyurethane elastomer material with high heat resistance and self-repairable ability to overcome the challenges encountered during the development of rubber tires. Results show that the polyurethane elastomer based on polycarbonate glycol, 1,5-naphthalene diisocyanate, and 1,4-butanediol simultaneously exhibits self-repairable ability, high heat resistance, low rolling resistance, high wear resistance, and high wet-skid resistance. The comprehensive performance of this material matches that of existing green tires. Moreover, the material can be recycled several times. This study is expected to solve the existing problems in rubber tires and provides novel ideas for preparing next-generation high-performance tire materials.

A COMPACT AND PORTABLE DESIGN DEVELOPMENT OF A LOW ROLLING RESISTANCE TEST RIG

Low Rolling Resistance (LRR) conveyor systems are generally preferred over traditional conveyors because of better overall efficiency lesser energy consumption required to operate. In this work, the design development and analysis path in the process of downscaling the size of an existent LRR test rig to a compact, portable and desktop-sized model is presented. Simulation has been developed using SolidWorks and finite element analysis is conducted using ANSYS to obtain the deformation, stress and strain of each part of the new design.

Study on mechanical properties and antifriction of calcium powder filled rubber

AbstractStudies show that long‐term operation of the rubber mixer results in wear at the end face of the mixer. End face wear increases the gap between the mixing chamber and the end face, which results in leakage and reduces the mixing performance, thereby affecting the quality of the final product. Therefore, it is of significant importance to investigate the wear of metal face during the mixing process. In the present study, calcium powder was added to the rubber compound using a mechanical blender to obtain a composite material. Then the influence of the calcium powder on metal friction and wear of the end face of the mixer was analyzed. The obtained results show that the calcium powder has anti‐friction properties, which can greatly reduce the compound wear on the metal. The lowest corrosion and wear of the compound on the metal was achieved with 5 phr of calcium powder. Meanwhile, it is found that the tensile and tear‐resistance properties of the compound with 5 phr of calcium powder are slightly lower than those without calcium powder. However, the compound with 5 phr of calcium powder has higher friction, cold resistance, wet slip resistance, and lower rolling resistance.

Evaluation of Rapid Repair of Concrete Pavements Using Precast Concrete Technology: A Sustainable and Cost-Effective Solution

Abstract Concrete and asphalt are the two competitive materials for a highway. In Sweden, the predominant material for the highway system is asphalt. But under certain conditions, concrete pavements are competitive alternatives. For example, concrete pavements are suitable for high-traffic volume roads, roads in tunnels, concentrated loads (e.g., bus stops and industrial pavement). Besides the load-carrying capacity, the concrete pavement has many advantages such as durability (wear resistance), resistance against frost heave, environment (pollution, recycling, and low rolling resistance leading to fuel savings), fire resistance, noise limitations, brightness, evenness and aesthetics. Concrete pavements are long-lasting but need final repair. Single slabs may crack in the jointed concrete pavement due to various structural and non-structural factors. Repair and maintenance operations are, therefore, necessary to increase the service life of the structures. To avoid extended lane closures, prevent traffic congestions, and expedite the pavement construction process, precast concrete technology is a recent innovative construction method that can meet the requirement of rapid construction and rehabilitation of the pavement. This paper evaluates rapid repair techniques of concrete pavement using precast concrete technology by analysing three case studies on jointed precast concrete pavements. The study showed that the required amount of time to re-open the pavement to traffic is dramatically reduced with jointed precast concrete panels.

Comparison between the effects of partial replacement of carbon black by carbon nanotubes and graphene on the performances of natural rubber composites

AbstractTo investigate comparatively the performances of natural rubber (NR) composites modified with graphene (Gr) and carbon nanotubes (CNTs), NR vulcanizates were prepared by partially replacing the carbon black with 3 phr Gr or CNTs, the properties such as cure, mechanical properties, tensile fatigue, wear resistance, and so on, were investigated. Results showed that both Gr and CNTs could lift the crosslinking density, lower the rolling resistance, and wet‐skid resistance of NR composites. In relative to CNTs, Gr degraded the manufacturing safety and cure rate of NR, displayed higher reinforcing effect than CNTs by upgrading tensile strength, modulus, and hardness. Besides, Gr/NR composite demonstrated better aging resistance than CNTs/NR. In comparison to Gr, CNTs could lift the manufacturing safety and cure rate of NR, maintain higher tear strength, result in better tensile fatigue resistance and wear resistance, reduce the heat buildup and the permanent compression set, further lower rolling resistance of NR while maintaining relatively higher wet‐skid resistance.

Advisor-Based Modelling of a Passenger-Type Fuel Cell Vehicle and the Effect of Movement Resistances on Battery Performance

The most important factors affecting the performance of electric driven vehicles are battery technology and movement resistance. Although many researches have been made on vehicle performance of battery technologies, the number of researches on the effect of movement resistances (rolling resistance, air resistance, road gradient resistance, transmission resistance) and accessory loss on vehicle performance is quite limited. In this study, modelling of a passenger-type fuel cell vehicle has been made on ADVISOR (ADVISOR-Advanced Vehicle Simulator) simulation programme, and effect of movement resistances and accessory losses on battery performance has been examined. At the end of the simulation, it has been determined that SOC (State of Change) value of the tire with low rolling resistance according to NEDC (New European Driving Cycle) driving cycle is higher than the tire with high rolling resistance by 2.2%; and that decrease of C_x A by two times has resulted in a decrease in SOC value by 1.3%. When vehicle-battery performance of transmission selection has been examined, it has been observed that higher friction loss occurred in 5-speed gearbox due to the differences between the gear rations of the gearbox, and average SOC value decreased by 1.4% due to the fact that accessory load was 1000 W instead of 700 W. During simulations made with relation to the incline of the road, usage of tire with low rolling resistance on road incline (ascend) of 5% resulted in a higher value of SOC by 2%. And on road incline (descend) of 5%, usage of tire with low rolling resistance resulted in a higher value of SOC by 2.2%.

Effect of the Functional Group Position in Functionalized Liquid Butadiene Rubbers Used as Processing Aids on the Properties of Silica-Filled Rubber Compounds.

Recently, research conducted on tread compounds with liquid butadiene rubber (LqBR) have been conducted in the tire industry. In particular, the introduction of functional groups into LqBRs is expected to lower hysteresis loss caused by the free chain ends of LqBR. To study this, LqBRs with functional groups at different positions were synthesized. The occurrences of in-chain and chain-end functionalization of functionalized LqBRs (F-LqBRs) were confirmed, the microstructure and functionalization efficiency of F-LqBRs were calculated through the characterizations. This novel functionalization technology was beneficial not only to immobilizing the free chain ends of LqBRs to the surfaces of silica to decrease the number of free chain ends, but also chemically bonding the LqBR chains on the base polymer through a crosslinking reaction to enhance the filler-rubber interaction. The effects of the functional group position and number of the free chain ends on the physical properties and hysteresis of the compounds were investigated by partially replacing the treated distillate aromatic extract (TDAE) oil with LqBR in silica-filled rubber compounds. The results showed that compounds that had applied DF-LqBR with both end functionalization performed better, including improving the silica dispersion, higher extraction resistance, and lower rolling resistance, than other F-LqBRs compounds.

Effect of Spoke Design and Material Nonlinearity on Non-Pneumatic Tire Stiffness and Durability Performance

Non-pneumatic tire has been widely used due to their advantages of no run-flat, no need of air maintenance, low rolling resistance, and improvement of passengers comfort due to its better shock absorption. It has variety of application in the military vehicle, earthmovers, lunar rover, stair climbing vehicles etc. Recently UPTIS (Unique Puncture-Proof Tire System) non pneumatic tire has been introduced for passenger vehicles. In this study three different design configuration Tweel, Honeycomb and newly developed UPTIS have been compared. Effect of Polyurethane (PU) material nonlinearity have also been introduced by applying 5 different nonlinear PU material property in the spokes. The combined analysis of the PU material nonlinearity and spoke design configuration on the overall tire stiffness and spoke damage prediction is analysed using 3-Dimensional FEM simulations performed in ANSYS 16.0. It has been observed that Mooney Rivlin 5-parameter model is best to capture all 5 studied PU materials the nonlinearity. Effect of material nonlinearity on various spoke designs have been studied. The best combination of spoke design and the use of nonlinear material have been suggested in terms of riding comfort, tire stiffness and durability performance.

Preparation of Low Rolling Resistance Modified Asphalt and Analysis of Its Rolling Resistance and Viscoelasticity

Preparation of Low Rolling Resistance Modified Asphalt and Analysis of Its Rolling Resistance and Viscoelasticity

Effect of Different Road Obstacles on the Structural Behavior of a Honeycomb Nonpneumatic Tire

ABSTRACTThe nonpneumatic tire (NPT), as the name suggests, is a type of tire that does not use air to support the load. Because of their outstanding advantages, such as durability and low rolling resistance, these tires have attracted much interest. The study of NPTs has drawn considerable recent attention, and some research was conducted to investigate their mechanical response. However, these studies did not consider an analysis of an NPT against obstacles. Therefore, in this article, the static and dynamic behaviors of an NPT with honeycomb structures rolling over different obstacles are investigated using numerical simulation. The flexible spokes, which are the most important part of NPTs, are assumed to have a honeycomb structure with the same cell wall thickness and angle. Based on the mesostructures hypothesis, these spokes are considered to be made of polyurethane material. To perform a more precise analysis, various parameters such as nonlinear properties of the material and contact condition are taken into account to establish the finite element model. The results, which can be used as a benchmark and are suitable for design purposes, are presented elaborately.

Rolling resistance and sinkage analysis by comparing FEM and experimental data for a grape transporting vehicle

In this study a 2D FEM model was developed to analyze ruts formation, rolling resistance, and power loss for a grape transporting cart aimed to replace the use of heavy tractors while harvesting grape. The model was supported by experiments in a vineyard in South Italy. Cone penetration tests were conducted to estimate frictional and cohesive properties in three soil conditions: firm, soft, and wet saturated. A tractor pulled test rig for a single wheel was developed to measure rolling resistance and sinkage, and complete the selection of the soil parameters. Completed the model, the analysis was conducted for a range of different wheel dimensions, and the outputs analyzed through response surfaces. The results showed the different impacts that width and diameter have on ruts formation and rolling resistance for different soil conditions. Wider wheels determined a main reduction of the sinkage, while the width contribution to the rolling resistance was affected by the total soil volume deformed. Larger diameters led to lower rolling resistance, with a higher impact on more deformable soils. Contact stress was compared with the thresholds recommended in the literature to determine the acceptable designs. This analysis represents a tool to select the running gear dimensions.

Improved tire tread compounds using functionalized styrene butadiene rubber‐silica filler/hybrid filler systems

AbstractAutomotive industry is currently looking for an eco‐friendly tire with low rolling resistance coefficient (RRc), better traction, wear resistance, and fatigue properties. Presently, solution styrene‐butadiene rubber (SSBR)‐silica systems are pursued for balancing between traction and RRc. However, the interaction between SSBR and silica is not enough to give satisfactory results. Functionalized‐SSBR (FSSBR) leads to better rubber‐silica interaction due to introduction of polar groups in the polymer chain. The present study investigates the influence of FSSBR, highly dispersible (HD) silica, and its hybrid filler systems with organically modified nanoclay (ONC) and exfoliated graphene nanoplatelet (xGnP). Both MH, and Δtorque were higher for the FSSBR‐HD silica compound (S1) with the lowest change in storage modulus (∆G') value, due to higher polymer‐filler interaction. S1 exhibited 16% ice traction and 12% wet traction improvement with 29% lower rolling resistance over SSBR‐silica compound. S1 showed the best wet traction rating and wear resistance. Replacing small portion of silica by ONC and xGnP improved the properties further. At 5 phr of nanofiller, TEM images revealed well‐dispersed nanofillers in the FSSBR matrix. The xGnP compound showed the least crack growth. For both the cases, abradability decreased with higher nanofiller amount, due to better reinforcement of the rubber.

An Empirical Tire-Wear Model for Heavy-Goods Vehicles

ABSTRACT Tire selection has an important impact on the operational costs of heavy-goods vehicles (HGVs). HGV tires are designed on a tradeoff between wear resistance, rolling resistance, and adhesion (skid resistance). High wear resistance tires (high mileage) are replaced less often but use more fuel during operation, and vice versa for low rolling resistance tires. Presently, finding the optimal tire to minimize replacement costs and fuel consumption (greenhouse gas emissions) is challenging due to the difficulty in predicting tire wear for a given operation, since its rate varies with different vehicle configurations (e.g., load, vehicle length, number of axles, type of axle, etc.) and road types (e.g., motorways/highways, minor roads, urban roads, etc.). This article presents a novel empirical tire-wear model that can be used to predict the wear for multi-axle vehicles based on route data and a vehicle model. The first part of the article presents the analytical and experimental development of the model. The second part presents the experimental validation of the model based on 10 months of in-service data totaling 37,000 km of operation. The model predicts tire tread depth within 8% (average error of 2%).

In situ generation of sulfur using silica as a carrier in the wet mixing of natural rubber latex

AbstractUsing sodium thiosulfate and hydrochloric acid as the raw materials and a silica aqueous dispersion as the carrier, sulfur is generated in situ by a chemical precipitation method, and an in situ sulfur‐silica/natural rubber (in situ S‐Silica/NR) composite is prepared. The in situ sulfur is characterized, and its effects on the natural rubber composites' cross‐linking density, vulcanization characteristics, mechanical properties, aging properties, dynamic mechanical properties, and Payne effect are studied. The experimental results show that the particle size of in situ sulfur is small, with a maximum of 5 μm, and the cross‐linking ability is stronger than commercial sulfur. Due to the strong surface adsorption force of silica, the interfacial bonding strength is enhanced, and the dispersion of the two components in the rubber matrix is improved. Compared with commercial sulfur‐silica/natural rubber (S‐Silica/NR) composites, the tensile strength is 20.3% higher, the elongation at break is 28.5% higher, and it better retains its aging properties and has a lower rolling resistance. This study provides a theoretical basis for the development of functional rubber vulcanizing agents and the preparation of high‐performance rubber composites.

New designed coupling agents for silica used in green tires with low VOCs and low rolling resistance

Bis-(γ-triethoxysilylpropyl)-tetrasulfide TESPT (Si69) is the most popular silane coupling agent for green tires. However, a large amount of alcohol vapours (a kind of volatile organic compounds (VOCs)) release when it is used for tire production, which can make the process harmful to tire quality and people’s health. In this work, Mx-Si69 (x = 1, 2, 3, 4, 5, 6), a series of silane coupling agents were successfully synthesized by transesterification of fatty alcohol polyoxyethylene ether-9 (AEO-9) with Si69. A series of Si69 molecule grafted with one to six fatty alcohol polyoxyethylene ether chains (the long alkoxy chain) (named as M1-Si69 to M6-Si69) were produced. The FT-IR and 1H NMR results revealed that six coupling agents named M1-Si69 ~ M6-Si69 could be obtained by adjusting the molar ratio of the reactive monomers. So, the VOCs emission could be reduced by 37.5%~100% theoretically because of the long chain reaction products. The FT-IR and TGA results demonstrated that Mx-Si69 could successfully modify silica. Then, silica/rubber compounds were prepared by adding these low VOCs coupling agents namely M1-Si69 ~ M6-Si69. The dynamic and static mechanical results indicated that silica/rubber compound made by adding M2-Si69 had the lowest Heat-Build up, the best wet skid resistance, and extremely low rolling resistance (it can save more than 20% energy consumption than Si69).

The effect of rolling resistance on people\u2019s willingness to cycle during wintertime

Harsh winters reduce utilitarian cycling in many cities. Using an online survey, we examined how increasing rolling resistance due to snow and ice affect people’s cycling willingness. The respondents (N = 1318) reported their willingness to cycle on various winter cycling conditions presented in photos. The answers were compared to the rolling resistance levels on the presented conditions, measured in a previous study. Respondents’ cycling willingness dropped from 91.2% at very low to 18.3% at very high rolling resistances. The cyclist’s age, gender, local climate, winter cycling experience and studded tire use affected the cycling willingness significantly. Electric bike usage did not affect cycling willingness. “Summer-only” cyclists did not cycle during the winter due to low temperatures (29%), lacked feeling of safety (27%), bicycle wear (17%), increased travel time (17%) and increased physical effort (10%). Hence, lower rolling resistance and increased use of studded tires can increase the cycling frequency of existing winter cyclists. To recruit new winter cyclists, the surface conditions should not only offer a low rolling resistance but should also be perceived as safe and comfortable.

Effect of feldspar filler on physical and dynamic properties of SBR/CB based tire tread compounds: Effect of addition method of silane coupling agent

In this work, the effects of using feldspar (FLD) as an alumina-silicate inorganic filler, with carbon black (CB) as a novel binary filler system, on the properties of SBR compounds were investigated for tire applications. The bis(triethoxysilylpropyl) disulfide (TESPD) was used for modification of FLD. The SBR hybrid composites were produced by replacing 10 phr of CB filler with neat FLD and functionalized FLD (F-FLD). The TESPD was added directly to the rubber mixture including neat FLD. The SBR composite which has only CB filler (50CB) was found to have the highest damping parameter (tan δ) value at 60°C. On the other hand, the composites loaded with the CB and the FLD fillers exhibited relatively lower tan δ at the same temperature showing lower rolling resistance meaning better fuel saving performance. The lowest rolling resistance was achieved for the 40CB-10F-FLD most probably due to its stronger interaction with the SBR elastomer molecules through the silane agent-assisted crosslinks of the F-FLD. As another dynamic property, the storage moduli at −20°C were found to be lower for the SBR hybrid composites as compared to that of the 50CB composite, exhibiting enhanced winter traction performance of the composites having FLD filler together with CB. The composites containing only 10 phr of FLD and F-FLD, on the other hand, exhibited very low tensile strength values which are not acceptable for tire tread materials.