Operating under the philosophy that play is a child's right,Anthill Creations,a non‑profit run by Pooja Rai,has so far built 283 different play spaces using almost entirely painted tires,featuring large tire sculp...Operating under the philosophy that play is a child's right,Anthill Creations,a non‑profit run by Pooja Rai,has so far built 283 different play spaces using almost entirely painted tires,featuring large tire sculptures of cars,buildings or animals,paired with more classic elements of swings,see‑saws and jungle gyms.展开更多
Multi-axle Swerve-drive Autonomous Mobile Robots(MS-AMRs)equipped with independently steerable wheels are commonly used for high-payload transportation.In this work,we present a novel Model Predictive Control(MPC)meth...Multi-axle Swerve-drive Autonomous Mobile Robots(MS-AMRs)equipped with independently steerable wheels are commonly used for high-payload transportation.In this work,we present a novel Model Predictive Control(MPC)method for MS-AGV trajectory tracking that takes tire wear minimization consideration in the objective function.To speed up the problem-solving process,we propose a hierarchical controller design and simplify the dynamic model by integrating the magic formula tire model and simplified tire wear model.In the experiment,the proposed method can be solved by simulated annealing in real-time on a normal personal computer and by incorporating tire wear into the objective function,tire wear is reduced by 19.19%while maintaining the tracking accuracy in curve-tracking experiments.In the more challenging scene:the desired trajectory is offset by 60 degrees from the vehicle's heading,the reduction in tire wear increased to 65.20%compared to the kinematic model without considering the tire wear optimization.展开更多
Non-metallic inclusions are a significant factor causing fractures during the manufacturing process of tire cord steel,and dissolution in the steel profoundly affects them.How the basicity and Al_(2)O_(3) content in S...Non-metallic inclusions are a significant factor causing fractures during the manufacturing process of tire cord steel,and dissolution in the steel profoundly affects them.How the basicity and Al_(2)O_(3) content in SiO_(2)-CaO-Al_(2)O_(3)-MgO refining slag affect non-metallic inclusions in tire cord steel at 1873 K was investigated.A quantitative relationship has been established between the slag basicity and the dissolved oxygen content in steel.The results demonstrate that non-metallic inclusions in steel transform along SiO_(2)-MnO-Al_(2)O_(3)→SiO_(2)-MnO system of inclusions.When the basicity is controlled within the range of 0.8-1.0,the corresponding dissolved oxygen content should be between 4×10^(−6) and 10×10^(−6).When Al_(2)O_(3) content in the refining slag is maintained at 5%,and the slag basicity is controlled between 0.8 and 1.0,or if the slag basicity is precisely 1.0 with Al_(2)O_(3) content kept below 11%,control over the plasticization of SiO_(2)-MnO-Al_(2)O_(3) system within the inclusions can be effectively achieved.Combined with thermodynamic calculation and measurement of the dissolved oxygen([O])activity in the steel,controlling SiO_(2)-MnO-Al_(2)O_(3)-like inclusions in the plastic region range can be achieved by adjusting the refining slag composition.展开更多
In this paper,the pyrolysis characteristics of waste tire rubber with catalyst addition were experimentally studied.Pyrolysis experimentations of waste tire rubber with either base,acid or Zeolite catalysts were perfo...In this paper,the pyrolysis characteristics of waste tire rubber with catalyst addition were experimentally studied.Pyrolysis experimentations of waste tire rubber with either base,acid or Zeolite catalysts were performed in a Thermal Gravimetric Analyzer,a one-stage test rig and a two-stage test rig respectively.This is followed by analysis into the rates of pyrolysis reactions and the yields and distribution of the three-phase products using thermogravimetric infrared spectroscopy(TG-IR)and gas chromatographymass spectrometry(GC-MS).Results indicated that the transition metal chloride catalysts improved the reaction rate and were overall effective than the solid acid-base catalysts.Benzene and toluene yields were improved by all three catalysts in the primary pyrolysis,and the best performance was achieved at 550℃ and 600℃ with 30%NaOH.With ZSM-5 in the secondary pyrolysis,proportion of high calorific gases components as H2 and CH4 were increased,and the arylation and isomerization reactions were also promoted.The optimum aromatics yield was achieved at 600℃ and 50%ZSM condition.This study would provide a reference for resourceful utilization of waste tires.展开更多
This study presents a fragility curve to assess explosively induced damage to military vehicle tires based on shock tube experiments.To replicate lateral damage scenarios that may occur in real battlefield environment...This study presents a fragility curve to assess explosively induced damage to military vehicle tires based on shock tube experiments.To replicate lateral damage scenarios that may occur in real battlefield environments involving missile or bomb detonations,extreme overpressure conditions were generated using a shock tube.The influence of explosive charge mass on tire damage was quantitatively evaluated.Experimental results identified two critical failure thresholds:for loss of pressure,the threshold was 354 kPa peak overpressure and 3052 kPa·ms impulse;for rupture,the values were 485 kPa and 4237 kPa-ms,respectively.The same damage profile was reproduced through finite element analysis(FEA),verifying the reliability of the simulation.A Single Degree of Freedom(SDOF)model and Kingery-Bulmash(K-B)chart were employed to generate pressure-impulse data as a function of standoff distance.These data were applied to a finite element tire model using the BLAST ENHANCED keyword in LS-DYNA.The applied peak overpressures were identical to the experimental values with a 24%-27%difference in impulse.The simulation also captured recurring bead rim separation phenomenon,leading to internal pressure loss consistent with high-speed camera observations from the experiments.The resulting fragility curve clearly defines the threshold conditions for tire damage and provides a standardized damage assessment model applicable to various explosive charge masses and stand-off distances.The proposed model offers a quantitative basis for evaluating tire vulnerability,providing foundational reference data for defense applications.Specifically,the findings are expected to serve as a reliable source for weapon effects analysis and target vulnerability assessments involving wheeled military vehicles.展开更多
The spoke as a key component has a significant impact on the performance of the non-pneumatic tire(NPT).The current research has focused on adjusting spoke structures to improve the single performance of NPT.Few studi...The spoke as a key component has a significant impact on the performance of the non-pneumatic tire(NPT).The current research has focused on adjusting spoke structures to improve the single performance of NPT.Few studies have been conducted to synergistically improve multi-performance by optimizing the spoke structure.Inspired by the concept of functionally gradient structures,this paper introduces a functionally gradient honeycomb NPT and its optimization method.Firstly,this paper completes the parameterization of the honeycomb spoke structure and establishes the numerical models of honeycomb NPTs with seven different gradients.Subsequently,the accuracy of the numerical models is verified using experimental methods.Then,the static and dynamic characteristics of these gradient honeycomb NPTs are thoroughly examined by using the finite element method.The findings highlight that the gradient structure of NPT-3 has superior performance.Building upon this,the study investigates the effects of key parameters,such as honeycomb spoke thickness and length,on load-carrying capacity,honeycomb spoke stress and mass.Finally,a multi-objective optimization method is proposed that uses a response surface model(RSM)and the Nondominated Sorting Genetic Algorithm-II(NSGA-II)to further optimize the functional gradient honeycomb NPTs.The optimized NPT-OP shows a 23.48%reduction in radial stiffness,8.95%reduction in maximum spoke stress and 16.86%reduction in spoke mass compared to the initial NPT-1.The damping characteristics of the NPT-OP have also been improved.The results offer a theoretical foundation and technical methodology for the structural design and optimization of gradient honeycomb NPTs.展开更多
Tires are integral to vehicular systems,directly influencing both safety and overall performance.Tradi-tional tire pressure inspection methods—such as manual or gauge-based approaches—are often time-consuming,prone ...Tires are integral to vehicular systems,directly influencing both safety and overall performance.Tradi-tional tire pressure inspection methods—such as manual or gauge-based approaches—are often time-consuming,prone to inconsistency,and lack the flexibility needed to meet diverse operational demands.In this research,we introduce an AI-driven tire pressure detection system that leverages an enhanced GoogLeNet architecture incorporating a novel Softplus-LReLU activation function.By combining the smooth,non-saturating characteristics of Softplus with a linear adjustment term,this activation function improves computational efficiency and helps stabilize network gradients,thereby mitigating issues such as gradient vanishing and neuron death.Our enhanced GoogLeNet algorithm was validated on a dedicated tire pressure image database comprising three categories-low pressure,normal pressure,and undetected.Experimental results revealed a classification accuracy of 98.518%within 11 min and 56 s of total processing time,substantially surpassing the original GoogLeNet’s 95.1852%and ResNet18’s 92.7778%.This performance gain is attributed to superior feature extraction within the Inception modules and the robust integration of our novel activation function,leading to improved detection reliability and faster inference.Beyond accuracy and speed,the proposed system offers significant benefits for real-time monitoring and vehicle safety by providing timely and precise tire pressure assessments.The automation facilitated by our AI-based method addresses the limitations of manual inspection,delivering consistent,high-quality results that can be easily scaled or customized for various vehicular platforms.Overall,this work establishes a solid foundation for advanced tire pressure monitoring systems and opens avenues for further exploration in AI-assisted vehicle maintenance,contributing to safer and more efficient automotive operations.展开更多
Utilizing the ballast layer with more durable and stable characteristics can help avoid significant expenses due to decreased maintenance efforts.Strengthening the ballast layer with different types of reinforcements ...Utilizing the ballast layer with more durable and stable characteristics can help avoid significant expenses due to decreased maintenance efforts.Strengthening the ballast layer with different types of reinforcements or substituting the stone aggregates with the appropriate granular materials could potentially help to achieve this goal by reducing the ballast deterioration.One of the exquisite and most effective solutions to eliminate these challenges is to use waste materials such as steel slag aggregates and useless tires.Utilizing these waste materials in the ballasted railway track will contribute to sustainable development,an eco-friendly system,and green infrastructure.So in a state-of-the-art insightful,the ballast aggregates,including a mixture of steel slag and stone aggregates,are reinforced with a novel kind of geo-grid made of waste tire strips known as geo-scraps.This laboratory research tried to explain the shear strength behavior of the introduced mixing slag-stone ballast reinforced with tire geo-scrap.To achieve this goal,a series of large-scale direct shear tests were performed on the ballast which is reinforced by tire geo-scrap and included various combinations of slag and stone aggregates.The concluded results indicate that the optimal mixing ratio is attained by a combination of 75%slag and 25%stone aggregates which is reinforced by tire geo-scrap at a placing level of 120 mm.In this case,the shear strength,internal friction angle,vertical displacement,and dilatancy angle of stone–slag ballast reinforced with geo-scraps exhibited average changes of+28%,+9%,-28%,and-15%,respectively.展开更多
Road traffic noise is a significant environmental issue in urban areas with major health and economic implications for communities.Thus,a comprehensive understanding of tire/road noise mechanism is crucial for road pa...Road traffic noise is a significant environmental issue in urban areas with major health and economic implications for communities.Thus,a comprehensive understanding of tire/road noise mechanism is crucial for road pavement engineering.This study evaluates the noise behaviour of six innovative microsurfacing mixtures incorporating natural and artificial aggregates(geopolymers and crumb rubber)with varying particle size distributions and binders.A 2D laser analysis aims at collecting surface texture indicators,while noise-related indicators were derived according to ISO 10844 standards.Noise levels were predicted using the SPERoN^(R)model(statistical physical explanation of rolling noise),analysing the vibro-dynamic and the aerodynamic contributions separately.Correlations between tire/road noise levels predicted by the model and surface texture indicators elucidate the key factors influencing noise generation mechanism.The findings indicate that lower nominal maximum aggregate size(NMAS)and uniformly shaped artificial aggregates substantially mitigate rolling noise.Moreover,profiles with negative skewness and positive kurtosis exhibit reduced noise generation.The study highlights the limitations of traditional indicators like the estimated noise difference due to texture(ENDT)and highlights the g-factor from the Abbott curve as a more reliable predictor of pavement noise properties.These findings provide valuable insights for designing low-noise pavements with enhanced performance,offering new perspectives on the noise behaviour and acoustic properties of microsurfacing.展开更多
Pollution from road traffic contributes significantly to air pollution through pollutants from exhaust emissions(gases and particles)and non-exhaust emissions(tire wear particles,brake wear particles and the resuspens...Pollution from road traffic contributes significantly to air pollution through pollutants from exhaust emissions(gases and particles)and non-exhaust emissions(tire wear particles,brake wear particles and the resuspension of road dust).This research examined the hazard of tire particles(TP)and in particular evaluated the effect of TP size on lung macrophages.TP were obtained by cryogenic grinding of a tire and subsequent sieving to obtain four groups of particles(TP70,TP30,TP15,TP5)of different sizes with average diameters of 107μm,55μm,22μm,and 6μm,respectively.A complete physicochemical characterization was performed to determine the size distribution,chemical composition and morphology of these particles.We then investigated the proinflammatory response,oxidative stress and cytotoxicity induced in RAW264.7 cells exposed to four different TP concentrations for 24 h.TP had no direct effect on cytotoxicity,nor did they increase reactive oxygen species(ROS)production in the cells.However,TP induced a significant and size-dependent proinflammatory effect,which was particularly pronounced with small particles.Moreover,this effect was concentration-dependent.展开更多
To improve the seismic performance of unrein-forced masonry(URM)buildings in the Himalayan re-gions,including Western China,India,Nepal,and Paki-stan,a low-cost bonded scrap tire rubber isolator(BSTRI)is proposed,and ...To improve the seismic performance of unrein-forced masonry(URM)buildings in the Himalayan re-gions,including Western China,India,Nepal,and Paki-stan,a low-cost bonded scrap tire rubber isolator(BSTRI)is proposed,and a series of vertical compression and horizontal shear tests are conducted.Incremental dynamic analyses are conducted for five types of BSTRI-supported URM buildings subjected to 22 far-field and 28 near-field earthquake ground motions.The resulting fragility curves and probability of damage curves are presented and utilized to evaluate the damage states of these buildings.The results show that in the base-isolated(BI)URM buildings under seismic ground motion at a peak ground acceleration(PGA)of 1.102g,the probability of exceeding the collapse prevention threshold is less than 25%under far-field earthquake ground motions and 31%under near-field earthquake ground motions.Furthermore,the maximum average vulnerability index for the BI-URM buildings,which are designed to withstand rare earthquakes with 9°(PGA=0.632g),is 40.87%for far-field earthquake ground motions and 41.83%for near-field earthquake ground motions.Therefore,the adoption of BSTRIs can significantly reduce the collapse probability of URM buildings.展开更多
Combined with the tire dynamics theoretical model,a rapid test method to obtain tire lateral and longitudinal both steady-state and transient characteristics only based on the tire quasi-steady-state test results is p...Combined with the tire dynamics theoretical model,a rapid test method to obtain tire lateral and longitudinal both steady-state and transient characteristics only based on the tire quasi-steady-state test results is proposed.For steady state data extraction,the test time of the rapid test method is half that of the conventional test method.For transient tire characteristics the rapid test method omits the traditional tire test totally.At the mean time the accuracy of the two method is much closed.The rapid test method is explained theoretically and the test process is designed.The key parameters of tire are extracted and the comparison is made between rapid test and traditional test method.The result show that the identification accuracy based on the rapid test method is almost equal to the accuracy of the conventional one.Then,the heat generated during the rapid test method and that generated during the conventional test are calculated separately.The comparison shows that the heat generated during the rapid test is much smaller than the heat generated during the conventional test process.This benefits to the reduction of tire wear and the consistency of test results.Finally,it can be concluded that the fast test method can efficiently,accurately and energy-efficiently measure the steady-state and transient characteristics of the tire.展开更多
Pneumatic tire modeling and validation have been the topic of several research papers, however, most of these papers only deal with pneumatic passenger and truck tires. In recent years, wheeled-scaled vehicles have ga...Pneumatic tire modeling and validation have been the topic of several research papers, however, most of these papers only deal with pneumatic passenger and truck tires. In recent years, wheeled-scaled vehicles have gained lots of attention as a feasible testing platform, nonetheless up to the authors’ knowledge there has been no research regarding the use of scaled tires and their effect on the overall vehicle performance characteristics. This paper presents a novel scaled electric combat vehicle tire model and validation technique. The pro-line lockdown tire size 3.00 × 7.35 is modeled using the Finite Element Analysis (FEA) technique and several materials including layered membrane, beam elements, and Mooney-Rivlin for rubber. The tire-rim assembly is then described, and the rigid body analysis is presented. The tire is then validated using an in-house custom-made static tire testing machine. The tire test rig is made specifically to test the pro-line tire model and is designed and manufactured in the laboratory. The tire is validated using vertical stiffness and footprint tests in the static domain at different operating conditions including several vertical loads. Then the tire is used to perform rolling resistance and steering analysis including the rolling resistance coefficient and the cornering stiffness. The analysis is performed at different operating conditions including longitudinal speeds of 5, 10, and 15 km/h. This tire model will be further used to determine the tractive and braking performance of the tire. Furthermore, the tire test rig will also be modified to perform cornering stiffness tests.展开更多
The presence of waste tires poses an environmental challenge as they occupy a significant amount of land and are expensive to dispose in landfills.However,reusing waste tires can address this issue when waste tires ar...The presence of waste tires poses an environmental challenge as they occupy a significant amount of land and are expensive to dispose in landfills.However,reusing waste tires can address this issue when waste tires are used in geotechnical applications.To determine the viability of this approach,laboratoryscale tests were conducted to investigate load-bearing capacity of circular footings on sand-tire shred(STS)mixtures with shredded waste tire contents of 5%e15%by weight and three different widths of shreds.The investigation focused on analyzing the thickness of layers composed of STS mixtures,the soil cap,and the impact of geogrids on bearing capacity.The results indicate that a specific mixture of sand and tire shreds provides the highest footing-bearing capacity.In addition,the optimal shred content and size were found to be 10%by weight and 2 cm×10 cm,respectively.Furthermore,for a given tire shred width,a particular length provides the largest bearing capacity.The results agree well with that of previous research conducted by the first author and his colleagues in direct shear and California bearing ratio(CBR)tests.The primary finding of this research is that the use of two-layered STS mixtures reinforced by geogrids significantly enhances the bearing capacity.展开更多
Aim To analyse the static temperature field ofthe solid rubber tire(SRT).Methods The mechanical and thermal FE models were developed and analyzed respectively with the FE software ANSYS.Results The maximum temperature...Aim To analyse the static temperature field ofthe solid rubber tire(SRT).Methods The mechanical and thermal FE models were developed and analyzed respectively with the FE software ANSYS.Results The maximum temperature becomes higher with the higher with the higher velocity of tire and scales down slightly with the higher convection coefficients.The mixed models are reasonable.Conclusion The study on static temperature field is important and reasonable.It gives the fundament for life analysis of SRT.展开更多
In order to estimate the trafficability of off-road vehicles, the linear relationships between the pressure and the stiffness of the tire and the action of the vertical tire force with the viscoelasticity are analyzed...In order to estimate the trafficability of off-road vehicles, the linear relationships between the pressure and the stiffness of the tire and the action of the vertical tire force with the viscoelasticity are analyzed. The method to improve the precision of the model by the coefficients is presented. The constitutive equation of the three-parameter linear model and the stiffness matrix of four-node isoparametric elements are derived to construct the FEM （finite element method） tire model in plan stress. A demarcation and verification system is designed based on the six-dimensional wheel force transducer and the vertical tire force is measured under different velocities. The results show that the model and the method proposed are reasonable.展开更多
Tire slip angle has a great influence on peak values of both logitudinal and lateral adhesion coefficients as well as optimal slip ratios. Regression equations based on the experi- mental data from several countries...Tire slip angle has a great influence on peak values of both logitudinal and lateral adhesion coefficients as well as optimal slip ratios. Regression equations based on the experi- mental data from several countries are given to describe their dependencies. The peak value of longitudiinal adhesion coefficient has a linear relationship with tire slip angle, but peak value of lateral has a complicated relationship; the optimal slip ratio of longitudinal has an exponent function relationship, the optimal slip ratio of lateral almost has nothinng to do with tire slipangle.展开更多
Facing the increasingly developing field of aviation and aerospace, the importance of aviation tire materials has increased significantly. This paper summarizes the performance requirements of aviation tires, introduc...Facing the increasingly developing field of aviation and aerospace, the importance of aviation tire materials has increased significantly. This paper summarizes the performance requirements of aviation tires, introduces the basic knowledge of aviation tires, and emphatically introduces and compares the performance characteristics and applications of various aviation tire skeleton materials.展开更多
文摘Operating under the philosophy that play is a child's right,Anthill Creations,a non‑profit run by Pooja Rai,has so far built 283 different play spaces using almost entirely painted tires,featuring large tire sculptures of cars,buildings or animals,paired with more classic elements of swings,see‑saws and jungle gyms.
基金supported by the National Research Foundation,Singapore,under its Medium-Sized Center for Advanced Robotics Technology Innovation(CARTIN)。
文摘Multi-axle Swerve-drive Autonomous Mobile Robots(MS-AMRs)equipped with independently steerable wheels are commonly used for high-payload transportation.In this work,we present a novel Model Predictive Control(MPC)method for MS-AGV trajectory tracking that takes tire wear minimization consideration in the objective function.To speed up the problem-solving process,we propose a hierarchical controller design and simplify the dynamic model by integrating the magic formula tire model and simplified tire wear model.In the experiment,the proposed method can be solved by simulated annealing in real-time on a normal personal computer and by incorporating tire wear into the objective function,tire wear is reduced by 19.19%while maintaining the tracking accuracy in curve-tracking experiments.In the more challenging scene:the desired trajectory is offset by 60 degrees from the vehicle's heading,the reduction in tire wear increased to 65.20%compared to the kinematic model without considering the tire wear optimization.
基金supported by the National Natural Science Foundation of China(Nos.52274337,52174317 and U1960203)2023 Liaoning Province Department of Education Fundamental Research Project Achievements(No.JYTMS20230928).
文摘Non-metallic inclusions are a significant factor causing fractures during the manufacturing process of tire cord steel,and dissolution in the steel profoundly affects them.How the basicity and Al_(2)O_(3) content in SiO_(2)-CaO-Al_(2)O_(3)-MgO refining slag affect non-metallic inclusions in tire cord steel at 1873 K was investigated.A quantitative relationship has been established between the slag basicity and the dissolved oxygen content in steel.The results demonstrate that non-metallic inclusions in steel transform along SiO_(2)-MnO-Al_(2)O_(3)→SiO_(2)-MnO system of inclusions.When the basicity is controlled within the range of 0.8-1.0,the corresponding dissolved oxygen content should be between 4×10^(−6) and 10×10^(−6).When Al_(2)O_(3) content in the refining slag is maintained at 5%,and the slag basicity is controlled between 0.8 and 1.0,or if the slag basicity is precisely 1.0 with Al_(2)O_(3) content kept below 11%,control over the plasticization of SiO_(2)-MnO-Al_(2)O_(3) system within the inclusions can be effectively achieved.Combined with thermodynamic calculation and measurement of the dissolved oxygen([O])activity in the steel,controlling SiO_(2)-MnO-Al_(2)O_(3)-like inclusions in the plastic region range can be achieved by adjusting the refining slag composition.
基金the Chongqing Municipal Education Commission Research Project(KJZD-K202401502)Chongqing Municipal Science&Technology Commission Research Project(CSTB2022NSCQ-LZX0071)to the research work.
文摘In this paper,the pyrolysis characteristics of waste tire rubber with catalyst addition were experimentally studied.Pyrolysis experimentations of waste tire rubber with either base,acid or Zeolite catalysts were performed in a Thermal Gravimetric Analyzer,a one-stage test rig and a two-stage test rig respectively.This is followed by analysis into the rates of pyrolysis reactions and the yields and distribution of the three-phase products using thermogravimetric infrared spectroscopy(TG-IR)and gas chromatographymass spectrometry(GC-MS).Results indicated that the transition metal chloride catalysts improved the reaction rate and were overall effective than the solid acid-base catalysts.Benzene and toluene yields were improved by all three catalysts in the primary pyrolysis,and the best performance was achieved at 550℃ and 600℃ with 30%NaOH.With ZSM-5 in the secondary pyrolysis,proportion of high calorific gases components as H2 and CH4 were increased,and the arylation and isomerization reactions were also promoted.The optimum aromatics yield was achieved at 600℃ and 50%ZSM condition.This study would provide a reference for resourceful utilization of waste tires.
基金part of the Agency for Defense Development(ADD)research project on Weapon lethality/effectiveness analysis technology for material targets and grant funded by the korean goverment(511225-912A03301)。
文摘This study presents a fragility curve to assess explosively induced damage to military vehicle tires based on shock tube experiments.To replicate lateral damage scenarios that may occur in real battlefield environments involving missile or bomb detonations,extreme overpressure conditions were generated using a shock tube.The influence of explosive charge mass on tire damage was quantitatively evaluated.Experimental results identified two critical failure thresholds:for loss of pressure,the threshold was 354 kPa peak overpressure and 3052 kPa·ms impulse;for rupture,the values were 485 kPa and 4237 kPa-ms,respectively.The same damage profile was reproduced through finite element analysis(FEA),verifying the reliability of the simulation.A Single Degree of Freedom(SDOF)model and Kingery-Bulmash(K-B)chart were employed to generate pressure-impulse data as a function of standoff distance.These data were applied to a finite element tire model using the BLAST ENHANCED keyword in LS-DYNA.The applied peak overpressures were identical to the experimental values with a 24%-27%difference in impulse.The simulation also captured recurring bead rim separation phenomenon,leading to internal pressure loss consistent with high-speed camera observations from the experiments.The resulting fragility curve clearly defines the threshold conditions for tire damage and provides a standardized damage assessment model applicable to various explosive charge masses and stand-off distances.The proposed model offers a quantitative basis for evaluating tire vulnerability,providing foundational reference data for defense applications.Specifically,the findings are expected to serve as a reliable source for weapon effects analysis and target vulnerability assessments involving wheeled military vehicles.
基金Supported by National Natural Science Foundation of China(Grant Nos.52072156,52272366)Postdoctoral Foundation of China(Grant No.2020M682269).
文摘The spoke as a key component has a significant impact on the performance of the non-pneumatic tire(NPT).The current research has focused on adjusting spoke structures to improve the single performance of NPT.Few studies have been conducted to synergistically improve multi-performance by optimizing the spoke structure.Inspired by the concept of functionally gradient structures,this paper introduces a functionally gradient honeycomb NPT and its optimization method.Firstly,this paper completes the parameterization of the honeycomb spoke structure and establishes the numerical models of honeycomb NPTs with seven different gradients.Subsequently,the accuracy of the numerical models is verified using experimental methods.Then,the static and dynamic characteristics of these gradient honeycomb NPTs are thoroughly examined by using the finite element method.The findings highlight that the gradient structure of NPT-3 has superior performance.Building upon this,the study investigates the effects of key parameters,such as honeycomb spoke thickness and length,on load-carrying capacity,honeycomb spoke stress and mass.Finally,a multi-objective optimization method is proposed that uses a response surface model(RSM)and the Nondominated Sorting Genetic Algorithm-II(NSGA-II)to further optimize the functional gradient honeycomb NPTs.The optimized NPT-OP shows a 23.48%reduction in radial stiffness,8.95%reduction in maximum spoke stress and 16.86%reduction in spoke mass compared to the initial NPT-1.The damping characteristics of the NPT-OP have also been improved.The results offer a theoretical foundation and technical methodology for the structural design and optimization of gradient honeycomb NPTs.
基金the National Science and Technology Council,Taiwan,for financially supporting this research(Grant No.NSTC 113-2221-E-018-011)Ministry of Education’s Teaching Practice Research Program,Taiwan(PSK1134099).
文摘Tires are integral to vehicular systems,directly influencing both safety and overall performance.Tradi-tional tire pressure inspection methods—such as manual or gauge-based approaches—are often time-consuming,prone to inconsistency,and lack the flexibility needed to meet diverse operational demands.In this research,we introduce an AI-driven tire pressure detection system that leverages an enhanced GoogLeNet architecture incorporating a novel Softplus-LReLU activation function.By combining the smooth,non-saturating characteristics of Softplus with a linear adjustment term,this activation function improves computational efficiency and helps stabilize network gradients,thereby mitigating issues such as gradient vanishing and neuron death.Our enhanced GoogLeNet algorithm was validated on a dedicated tire pressure image database comprising three categories-low pressure,normal pressure,and undetected.Experimental results revealed a classification accuracy of 98.518%within 11 min and 56 s of total processing time,substantially surpassing the original GoogLeNet’s 95.1852%and ResNet18’s 92.7778%.This performance gain is attributed to superior feature extraction within the Inception modules and the robust integration of our novel activation function,leading to improved detection reliability and faster inference.Beyond accuracy and speed,the proposed system offers significant benefits for real-time monitoring and vehicle safety by providing timely and precise tire pressure assessments.The automation facilitated by our AI-based method addresses the limitations of manual inspection,delivering consistent,high-quality results that can be easily scaled or customized for various vehicular platforms.Overall,this work establishes a solid foundation for advanced tire pressure monitoring systems and opens avenues for further exploration in AI-assisted vehicle maintenance,contributing to safer and more efficient automotive operations.
文摘Utilizing the ballast layer with more durable and stable characteristics can help avoid significant expenses due to decreased maintenance efforts.Strengthening the ballast layer with different types of reinforcements or substituting the stone aggregates with the appropriate granular materials could potentially help to achieve this goal by reducing the ballast deterioration.One of the exquisite and most effective solutions to eliminate these challenges is to use waste materials such as steel slag aggregates and useless tires.Utilizing these waste materials in the ballasted railway track will contribute to sustainable development,an eco-friendly system,and green infrastructure.So in a state-of-the-art insightful,the ballast aggregates,including a mixture of steel slag and stone aggregates,are reinforced with a novel kind of geo-grid made of waste tire strips known as geo-scraps.This laboratory research tried to explain the shear strength behavior of the introduced mixing slag-stone ballast reinforced with tire geo-scrap.To achieve this goal,a series of large-scale direct shear tests were performed on the ballast which is reinforced by tire geo-scrap and included various combinations of slag and stone aggregates.The concluded results indicate that the optimal mixing ratio is attained by a combination of 75%slag and 25%stone aggregates which is reinforced by tire geo-scrap at a placing level of 120 mm.In this case,the shear strength,internal friction angle,vertical displacement,and dilatancy angle of stone–slag ballast reinforced with geo-scraps exhibited average changes of+28%,+9%,-28%,and-15%,respectively.
基金funded by the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement N°765057(SAFERUP Project).
文摘Road traffic noise is a significant environmental issue in urban areas with major health and economic implications for communities.Thus,a comprehensive understanding of tire/road noise mechanism is crucial for road pavement engineering.This study evaluates the noise behaviour of six innovative microsurfacing mixtures incorporating natural and artificial aggregates(geopolymers and crumb rubber)with varying particle size distributions and binders.A 2D laser analysis aims at collecting surface texture indicators,while noise-related indicators were derived according to ISO 10844 standards.Noise levels were predicted using the SPERoN^(R)model(statistical physical explanation of rolling noise),analysing the vibro-dynamic and the aerodynamic contributions separately.Correlations between tire/road noise levels predicted by the model and surface texture indicators elucidate the key factors influencing noise generation mechanism.The findings indicate that lower nominal maximum aggregate size(NMAS)and uniformly shaped artificial aggregates substantially mitigate rolling noise.Moreover,profiles with negative skewness and positive kurtosis exhibit reduced noise generation.The study highlights the limitations of traditional indicators like the estimated noise difference due to texture(ENDT)and highlights the g-factor from the Abbott curve as a more reliable predictor of pavement noise properties.These findings provide valuable insights for designing low-noise pavements with enhanced performance,offering new perspectives on the noise behaviour and acoustic properties of microsurfacing.
基金supported by the Ecole des Mines Saint-Etienne and the Agence de l’Environnement et de la Maitrise de l’Energie。
文摘Pollution from road traffic contributes significantly to air pollution through pollutants from exhaust emissions(gases and particles)and non-exhaust emissions(tire wear particles,brake wear particles and the resuspension of road dust).This research examined the hazard of tire particles(TP)and in particular evaluated the effect of TP size on lung macrophages.TP were obtained by cryogenic grinding of a tire and subsequent sieving to obtain four groups of particles(TP70,TP30,TP15,TP5)of different sizes with average diameters of 107μm,55μm,22μm,and 6μm,respectively.A complete physicochemical characterization was performed to determine the size distribution,chemical composition and morphology of these particles.We then investigated the proinflammatory response,oxidative stress and cytotoxicity induced in RAW264.7 cells exposed to four different TP concentrations for 24 h.TP had no direct effect on cytotoxicity,nor did they increase reactive oxygen species(ROS)production in the cells.However,TP induced a significant and size-dependent proinflammatory effect,which was particularly pronounced with small particles.Moreover,this effect was concentration-dependent.
基金The National Natural Science Foundation of China(No.52208195)the Independent Subject of State Key Laboratory of Disaster Reduction in Civil Engineering of Tongji University(No.SLDRCE19-A-10).
文摘To improve the seismic performance of unrein-forced masonry(URM)buildings in the Himalayan re-gions,including Western China,India,Nepal,and Paki-stan,a low-cost bonded scrap tire rubber isolator(BSTRI)is proposed,and a series of vertical compression and horizontal shear tests are conducted.Incremental dynamic analyses are conducted for five types of BSTRI-supported URM buildings subjected to 22 far-field and 28 near-field earthquake ground motions.The resulting fragility curves and probability of damage curves are presented and utilized to evaluate the damage states of these buildings.The results show that in the base-isolated(BI)URM buildings under seismic ground motion at a peak ground acceleration(PGA)of 1.102g,the probability of exceeding the collapse prevention threshold is less than 25%under far-field earthquake ground motions and 31%under near-field earthquake ground motions.Furthermore,the maximum average vulnerability index for the BI-URM buildings,which are designed to withstand rare earthquakes with 9°(PGA=0.632g),is 40.87%for far-field earthquake ground motions and 41.83%for near-field earthquake ground motions.Therefore,the adoption of BSTRIs can significantly reduce the collapse probability of URM buildings.
基金Supported by National Natural Science Foundation of China(Grant No.51775224).
文摘Combined with the tire dynamics theoretical model,a rapid test method to obtain tire lateral and longitudinal both steady-state and transient characteristics only based on the tire quasi-steady-state test results is proposed.For steady state data extraction,the test time of the rapid test method is half that of the conventional test method.For transient tire characteristics the rapid test method omits the traditional tire test totally.At the mean time the accuracy of the two method is much closed.The rapid test method is explained theoretically and the test process is designed.The key parameters of tire are extracted and the comparison is made between rapid test and traditional test method.The result show that the identification accuracy based on the rapid test method is almost equal to the accuracy of the conventional one.Then,the heat generated during the rapid test method and that generated during the conventional test are calculated separately.The comparison shows that the heat generated during the rapid test is much smaller than the heat generated during the conventional test process.This benefits to the reduction of tire wear and the consistency of test results.Finally,it can be concluded that the fast test method can efficiently,accurately and energy-efficiently measure the steady-state and transient characteristics of the tire.
文摘Pneumatic tire modeling and validation have been the topic of several research papers, however, most of these papers only deal with pneumatic passenger and truck tires. In recent years, wheeled-scaled vehicles have gained lots of attention as a feasible testing platform, nonetheless up to the authors’ knowledge there has been no research regarding the use of scaled tires and their effect on the overall vehicle performance characteristics. This paper presents a novel scaled electric combat vehicle tire model and validation technique. The pro-line lockdown tire size 3.00 × 7.35 is modeled using the Finite Element Analysis (FEA) technique and several materials including layered membrane, beam elements, and Mooney-Rivlin for rubber. The tire-rim assembly is then described, and the rigid body analysis is presented. The tire is then validated using an in-house custom-made static tire testing machine. The tire test rig is made specifically to test the pro-line tire model and is designed and manufactured in the laboratory. The tire is validated using vertical stiffness and footprint tests in the static domain at different operating conditions including several vertical loads. Then the tire is used to perform rolling resistance and steering analysis including the rolling resistance coefficient and the cornering stiffness. The analysis is performed at different operating conditions including longitudinal speeds of 5, 10, and 15 km/h. This tire model will be further used to determine the tractive and braking performance of the tire. Furthermore, the tire test rig will also be modified to perform cornering stiffness tests.
文摘The presence of waste tires poses an environmental challenge as they occupy a significant amount of land and are expensive to dispose in landfills.However,reusing waste tires can address this issue when waste tires are used in geotechnical applications.To determine the viability of this approach,laboratoryscale tests were conducted to investigate load-bearing capacity of circular footings on sand-tire shred(STS)mixtures with shredded waste tire contents of 5%e15%by weight and three different widths of shreds.The investigation focused on analyzing the thickness of layers composed of STS mixtures,the soil cap,and the impact of geogrids on bearing capacity.The results indicate that a specific mixture of sand and tire shreds provides the highest footing-bearing capacity.In addition,the optimal shred content and size were found to be 10%by weight and 2 cm×10 cm,respectively.Furthermore,for a given tire shred width,a particular length provides the largest bearing capacity.The results agree well with that of previous research conducted by the first author and his colleagues in direct shear and California bearing ratio(CBR)tests.The primary finding of this research is that the use of two-layered STS mixtures reinforced by geogrids significantly enhances the bearing capacity.
文摘Aim To analyse the static temperature field ofthe solid rubber tire(SRT).Methods The mechanical and thermal FE models were developed and analyzed respectively with the FE software ANSYS.Results The maximum temperature becomes higher with the higher with the higher velocity of tire and scales down slightly with the higher convection coefficients.The mixed models are reasonable.Conclusion The study on static temperature field is important and reasonable.It gives the fundament for life analysis of SRT.
文摘In order to estimate the trafficability of off-road vehicles, the linear relationships between the pressure and the stiffness of the tire and the action of the vertical tire force with the viscoelasticity are analyzed. The method to improve the precision of the model by the coefficients is presented. The constitutive equation of the three-parameter linear model and the stiffness matrix of four-node isoparametric elements are derived to construct the FEM （finite element method） tire model in plan stress. A demarcation and verification system is designed based on the six-dimensional wheel force transducer and the vertical tire force is measured under different velocities. The results show that the model and the method proposed are reasonable.
文摘Tire slip angle has a great influence on peak values of both logitudinal and lateral adhesion coefficients as well as optimal slip ratios. Regression equations based on the experi- mental data from several countries are given to describe their dependencies. The peak value of longitudiinal adhesion coefficient has a linear relationship with tire slip angle, but peak value of lateral has a complicated relationship; the optimal slip ratio of longitudinal has an exponent function relationship, the optimal slip ratio of lateral almost has nothinng to do with tire slipangle.
文摘Facing the increasingly developing field of aviation and aerospace, the importance of aviation tire materials has increased significantly. This paper summarizes the performance requirements of aviation tires, introduces the basic knowledge of aviation tires, and emphatically introduces and compares the performance characteristics and applications of various aviation tire skeleton materials.
