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Development of an Accelerated Test for Tire Flat-Spotting

NissanTechnical Center North America-Farokh Kavarana, Scott Fritz
Published 2019-06-05 by SAE International in United States
Tire flat-spotting occurs when tires remain in a loaded condition without rolling for an extended period of time, and can be temporary or permanent depending on the length of storage, vehicle loading and environmental factors. Tire non-uniformity caused from flat-spots often induce shake and shimmy vibration in vehicles due to increased tire-wheel force variation input into the chassis. This results in increased warranty costs for OEMs and tire suppliers and customer dis-satisfaction in third-party quality surveys such as J. D. Power IQS. Flat-spotting is of particular concern for slow-moving vehicle inventory parked for long periods at plants and/or dealership lots.OEMs often stipulate or recommend inventory storage practices for dealers that require physical movement of vehicles at some set duration to reduce the risk of tires developing permanent flat-spots. OEMs also provide component level flat-spotting requirements to tire manufacturers during sourcing and specification timing to secure their internal requirements and targets. The study in this paper initially determined real-world flat-spotting levels on an actual vehicle during the adverse summer months of Arizona. Tire uniformity measured on…
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A Review on Physical Mechanisms of Tire-Pavement Interaction Noise

SAE International Journal of Vehicle Dynamics, Stability, and NVH

Maxxis International, USA-Tan Li
  • Journal Article
  • 10-03-02-0007
Published 2019-05-16 by SAE International in United States
Tire-pavement interaction noise (TPIN) dominates for passenger cars above 40 km/h and trucks above 70 km/h. Numerous studies have attempted to uncover and distinguish the basic mechanisms of TPIN. However, intense debate is still ongoing about the validity of these mechanisms. In this work, the physical mechanisms proposed in the literature were reviewed and divided into three categories: generation mechanisms, amplification mechanisms, and attenuation mechanisms. The purpose of this article is to gather the published general opinions for further open discussions.
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HSTANDARD FOR TIRE TRACEABILITY CONTENT AND FORMAT FOR THE RADIO-FREQUENCY IDENTIFICATION (RFID) TAG AND ASSOCIATED TIRE DATA SET

USCAR
  • Ground Vehicle Standard
  • USCAR39
  • Current
Published 2019-04-17 by SAE International in United States
This standard describes a requirement for automotive tire traceability. It includes a definition of the RFID tag and the associated tire data set that can be accessed using the RFID tag as an identifier. The standard describes a unique identification and the associated data set for each tire produced by the tire fabricator. This data will either be provided or transmitted at the time of shipment to retailers, wholesalers or original equipment vehicle manufacturers. Tire identification code and data may be used for error proofing, determining the tire specifications or supporting any inquiries that occur for the duration of its automotive life.
 

Landing Gear Shock Absorption Testing of Civil Aircraft

A-5B Gears, Struts and Couplings Committee
  • Aerospace Standard
  • ARP5644
  • Current
Published 2019-04-17 by SAE International in United States
The intent of this document is to provide recommended practices for conducting shock absorption testing of civil aircraft landing gear equipped with oleo-pneumatic shock absorbers. The primary focus is for Part 25 aircraft, but differences for Part 23, 27, and 29 aircraft are provided where appropriate.
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Multi-Chamber Tire Concept for Low Rolling-Resistance

SAE International Journal of Passenger Cars - Mechanical Systems

University of Birmingham, UK-Hamad Sarhan Aldhufairi, Khamis Essa, Oluremi Olatunbosun
  • Journal Article
  • 06-12-02-0009
Published 2019-04-08 by SAE International in United States
Rolling-resistance is leading the direction of numerous tire developments due to its significant effect on fuel consumption and CO2 emissions considering the vehicles in use globally. Many attempts were made to reduce rolling-resistance in vehicles, but with no or limited success due to tire complexity and trade-offs. This article investigates the concept of multiple chambers inside the tire as a potential alternative solution for reducing rolling-resistance. To accomplish that, novel multi-chamber designs were introduced and numerically simulated through finite-element (FE) modeling. The FE models were compared against a standard design as the baseline. The influences on rolling-resistance, grip, cornering, and mechanical comfort were studied. The multi-chambers tire model reduced rolling-resistance considerably with acceptable trade-offs. Independent air volumes isolating the tread from sidewalls would maintain tire’s profile effectively. Different air concentration across the tire’s chambers gave the tire extended versatility. Rolling non-uniformity depends upon inner-chambers’ stability, sidewalls’ flexibility and tire/chamber(s) integration.
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A Combination of Intelligent Tire and Vehicle Dynamic Based Algorithm to Estimate the Tire-Road Friction

SAE International Journal of Passenger Cars - Mechanical Systems

NIO, USA-Omid Ghasemalizadeh
Texas State University, USA-Seyedmeysam Khaleghian
  • Journal Article
  • 06-12-02-0007
Published 2019-04-08 by SAE International in United States
One of the most important factors affecting the performance of vehicle active chassis control systems is the tire-road friction coefficient. Accurate estimation of the friction coefficient can lead to better performance of these controllers. In this study, a new three-step friction estimation algorithm, based on intelligent tire concept, is proposed, which is a combination of experiment-based and vehicle dynamic based approaches. In the first step of the proposed algorithm, the normal load is estimated using a trained Artificial Neural Network (ANN). The network was trained using the experimental data collected using a portable tire testing trailer. In the second step of the algorithm, the tire forces and the wheel longitudinal velocity are estimated through a two-step Kalman filter. Then, in the last step, using the estimated tire normal load and longitudinal and lateral forces, the friction coefficient can be estimated. To evaluate the performance of the algorithm, experiments were performed using the trailer test setup and friction was calculated using the measured forces. Good agreement was observed between the estimated and actual friction coefficients.
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Control-Oriented Modeling of a Vehicle Drivetrain for Shuffle and Clunk Mitigation

Ford Research & Advanced Engineering-Maruthi Ravichandran, Mary Farmer, Jeff Doering
Michigan Technological University-Prithvi Reddy, Kaushal Darokar, Darrell Robinette, Mahdi Shahbakhti, Jason Blough
  • Technical Paper
  • 2019-01-0345
Published 2019-04-02 by SAE International in United States
Flexibility and backlash of vehicle drivelines typically cause unwanted oscillations and noise, known as shuffle and clunk, during tip-in and tip-out events. Computationally efficient and accurate driveline models are necessary for the design and evaluation of torque shaping strategies to mitigate this shuffle and clunk. To accomplish these goals, this paper develops a full-order physics-based model and uses this model to develop a reduced-order model (ROM), which captures the main dynamics that influence the shuffle and clunk phenomena. The full-order model (FOM) comprises several components, including the engine as a torque generator, backlash elements as discontinuities, and propeller and axle shafts as compliant elements. This model is experimentally validated using the data collected from a Ford vehicle. The validation results indicate less than 1% error between the model and measured shuffle oscillation frequencies. The reduced-order model is derived by lumping 24 inertia elements into 2 elements, 3 stiffness and damping elements into 2 elements, and 2 backlashes into 1 element. As part of the reduced-order model development, the paper (i) investigates the effect of using…
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Some Experimental Studies on the Use of Tyre Pyrolysis Oil (TPO) in an Agricultural Diesel Engine

CASRAE, Delhi Technological University-Naveen Kumar
Maharaja Agrasen Institute of Technology-Ashwni Goyal
Published 2019-04-02 by SAE International in United States
Globally, the demand for energy is increasing due to both increase in population and enhancement in the lifestyle of people. Most of the energy demand at present is met from fossil fuels, which are not only exhaustible but also a threat to the environment. Various routes of sustainable energy resources are being explored to address the above-mentioned issues and fuel made from used tyre may be one of the promising options.India is one of the fastest growing economies and every year 10 million new vehicles are registered. Due to poor road conditions, nearly fourfold tyres of this number are dumped as waste. This large stock of dumped tyres are non-biodegradable and creates other problems like a breeding site for mosquitos, or source of pollution in case of accidental fire. In order to cope with the large pile-up of used tyres, pyrolysis of these tyres could be a sustainable route. Pyrolysis is a thermo-chemical process carried in absence of oxygen and a sustainable option for conversion into Tyre Pyrolysis Oil (TPO).In the present work, the performance…
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Research on Technique for Correction of Running Resistance with Focus on Tire Temperature and Tire Thermal Balance Model

Honda R&D Co., Ltd.-Takeshi Hotaka, Tomonori Sakai, Hideki Miura
Published 2019-04-02 by SAE International in United States
At present, measurements of running resistance are conducted outdoors as a matter of course. Because of this, the ambient temperature at the time of the measurements has a considerable impact on the measurement data. The research discussed in this paper focused on the temperature characteristic of the tires and developed a new correction technique using a special rolling test apparatus. Specifically, using a tire rolling test apparatus that made it possible to vary the ambient temperature, measurements were conducted while varying the levels of factors other than temperature that affect rolling resistance (load, inflation pressure, and speed). Next, a regression analysis was applied to the data for each factor, and coefficients for a relational expression were derived, making it possible to derive a quadratic equation for the tire rolling resistance correction formula. It was verified that the application of the new correction formula reduced variation in running resistance from 2.7% (in the case of regulation correction) to 1.0%.In addition, in order to offer a simpler method of realizing the same correction, a technique for correction…
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A Mathematical Analysis of Off-Road Vehicle to Avoid “Hang Up” and “Nose In” Failures

Georgia Southern University-Aniruddha Mitra, Keith Russell
Published 2019-04-02 by SAE International in United States
The goal of this study was to determine the design constraints for the Georgia Southern SAE BAJA vehicle to operate in a rough terrain without unwanted direct body impact. The BAJA vehicle may encounter two distinct kinds of failure while climbing or descending terrain obstacles: Hang up failure, and Nose in failure. Hang up failure occurs when the bottom of the chassis of the vehicle makes contact with the obstacle. This occurs after the front tires have cleared the obstacle but before the rear tires have. This mitigates the pace of the vehicle but does not structurally threaten it. Nose in failure is when the protruding front bumper or “nose” of the vehicle makes contact with either the ground or the obstacle before or after encountering the obstacle. The possible ramifications of this event are much more disastrous than the Hang up failure. Nose in failure can send the vehicle into an end over end flip, or cause significant structural damage to the frame. Through a geometric analysis of the two situations, the critical values…
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