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Characterisation of Brake Creep Groan Vibrations

Graz University of Technology-Peter Fischer, Manuel Pürscher, Severin Huemer-Kals
University of Ljubljana-Jurij Prezelj
  • Technical Paper
  • 2020-01-1505
To be published on 2020-06-03 by SAE International in United States
Creep Groan is an impulsive brake noise at very low velocities of the vehicle. Generally, stick-slip between brake disc and brake pads is assumed as the most dominating vibration mechanism of creep groan. This contribution will show by sophisticated measurement techniques, that stick-slip and speed dependent friction is an important trigger of this annoying vehicle noise. However, the overall vibration is much more complex than common stick-slip vibration models. It turns out, that in typical brake systems of passenger vehicles creep groan occurs around 15-20 Hz and 70-90 Hz. The mechanism at 15-20 Hz is an impulsive noise. Transitions between stick and slip phases trigger complex nonlinear vibrations of the complete brake and suspension system. At 70-90 Hz, the vibrations show a more harmonic-like behaviour, caused primarily by speed-dependent friction characteristics. Flexibilities in the suspension bushings, elastic deformations of suspension parts, wheel and tyre support the growth of instable self excited vibrations. In practical vehicle operation, the range of 70-90 Hz is the most relevant one. In many cases, the 15-20 Hz vibrations are not…
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Measurement Location Optimization of Component TPA Method for Road Noise

Applus + Idiada Spain-Onno de Boer, Javier Iturbe
Applus Idiada-Beatriz Bragado Pérez
  • Technical Paper
  • 2020-01-1581
To be published on 2020-06-03 by SAE International in United States
In this paper, an investigation on the application of a non-intrusive on-site component Transfer Path Analysis (TPA) method is presented together with the comparison with a previously performed direct blocked forces method. The latter is the more common method to determine interface forces between active and passive parts of an assembly. Force transducers are placed between the investigated structure and a rigid measurement rig. The presented comparison shows an investigated whether the faster and cheaper TPA method was able to produce relevant results. The TPA method used in this work calculated the force component contributions, without disassembly of the interfaces, through the local stiffness of multiple indicator positions per interface combined with operational measurement. The method is based on the application of an inverse-matrix model. This approach was applied to a vehicle road noise investigation carried out on a roller bench at three different roller speeds. A rough surface single axle roller bench in the same conditions as for the blocked forces method was used. The matrix inversion was carried out by using an overdetermined…
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Simulation of the performance of solar driven thermoelectric based rotary desiccant wheel HVAC system

Vellore Inst. of Technology, Vellore-Selvaraji Muthu, Sekarapandian N
  • Technical Paper
  • 2020-28-0041
To be published on 2020-04-30 by SAE International in United States
In the automotive applications, the main functionality of the HVAC system includes, heating, ventilation, and cooling or air-conditioning of the vehicle interior to achieve the desired indoor thermal comfort. In the current scenario conventional vapor compression based HVAC system are widely used for this application. The typical refrigerants used to operate this equipment include HFCs and HFOs which are susceptible to cause environmental hazard. The aim of this article is to assess the performance of a hypothetical solar driven thermoelectric based rotary desiccant wheel HVAC system (D-HVAC) to be used for automotive applications. The D-HVAC system uses desiccant wheel to remove the latent heat, energy wheel to remove the sensible heat, evaporating coolers to achieve further cooling, the regeneration of the desiccant wheel by hot air and water as the refrigerant. In the case of solar driven–DHVAC system, the solar energy is utilized for regeneration of desiccant wheel in place of hot air. However, the intensity of incident solar energy varies throughout the day. To compensate for this energy fluctuation an an additional thermoelectric system…
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Trajectory Planning and Tracking for Four-Wheel-Steering Autonomous Vehicle with V2V Communication

Jilin University-Fangwu Ma, Yucheng Shen, Jiahong Nie, Xiyu Li, Yu Yang, Jiawei Wang, Guanpu Wu
  • Technical Paper
  • 2020-01-0114
To be published on 2020-04-14 by SAE International in United States
Lane-changing is a typical traffic scene effecting on road traffic with high request for reliability, robustness and driving comfort to improve the road safety and transportation efficiency. The development of connected autonomous vehicles with V2V communication provide more advanced control strategies to research of lane-changing. Meanwhile, four-wheel steering is an effective way to improve flexibility of vehicle. The front and rear wheels rotate in opposite direction to reduce the turning radius to improve the servo agility operation at the low speed while those rotate in same direction to reduce the probability of the slip accident to improve the stability at the high speed. Hence, this paper established Four-Wheel-Steering(4WS) vehicle dynamic model and quasi real lane-changing scenes to analyze the motion constraints of the vehicles. Then, the polynomial function was used for the lane-changing trajectory planning and the extended rectangular vehicle model was established to get vehicle collision avoidance condition. Vehicle comfort requirements and lane-changing efficiency were used as the optimization variables of optimization function and the control of trajectory tracking can be obtained by using…
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Acoustic Characteristics Prediction and Optimization of Wheel Resonators with Arbitrary Section

SAIC Motor Corporation Limited-Yimin Sun, Junlei Mao
Tongji University-Rong Guo, Tiantian Mi
  • Technical Paper
  • 2020-01-0917
To be published on 2020-04-14 by SAE International in United States
Tire cavity noise of pure electric vehicles is particularly prominent due to the absence of engine noise, which are usually eliminated by adding Helmholtz resonators with arbitrary transversal section to the wheel rims. This paper provides theoretical basis for accurately predicting and effectively improving acoustic performance of wheel resonators. A hybrid finite element method is developed to extract the transversal wavenumbers and eigenvectors, and the mode-matching scheme is employed to determine the transmission loss of the Helmholtz resonator. Based on the accuracy validation of this method, the matching design of the wheel resonators and the optimization method of tire cavity noise are studied. The identification method of the tire cavity resonance frequency is developed through the acoustic modal test. A scientific transmission loss target curve and fitness function are defined according to the noise characteristics. Combing the transmission loss prediction theory and particle swarm algorithm, the structural parameters of the wheel resonator are optimized. A remarkable attenuation of tire cavity resonance can be observed through test results.
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Impact of Rim Orientation on Road Vehicles Aerodynamics Simulations

Graz University of Technology-Wolfgang von der Linden, Günter Brenn
Magna Steyr Fahrzeugtechnik AG & Co KG-Gernot Bukovnik
  • Technical Paper
  • 2020-01-0674
To be published on 2020-04-14 by SAE International in United States
Aerodynamic CFD simulations in the automotive industry based on the steady-state RANS (Reynolds-averaged Navier–Stokes) approach typically utilize approximate numerical methods to account for rotating wheels. In these methods, the computational mesh representing the rim geometry remains stationary, and the influence of the wheel rotation on the air flow is modelled. As the rims are considered only in one fixed rotational position (chosen arbitrarily in most cases), the effects of the rim orientation on the aerodynamic simulation results are disregarded and remain unquantified. This paper presents a numerical sensitivity study to examine the impact of the rim orientation position on the aerodynamic parameters of a detailed production vehicle. The simulations are based on the steady-state RANS approach. These investigations are carried out for three rim geometries, and for simulation cases with stationary and rotating wheels for comparison, where the Moving Wall (MW) and the Moving Reference Frame (MRF) methods, as well as combinations of the two approaches are used to model the wheel rotation. For the test vehicle, alterations in the flow field, and subsequently an…
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Facility for Complete Characterization of Suspension Kinematic and Compliance Properties of Wheeled Military Vehicles

SEA, Ltd.-Dale Andreatta, Gary Heydinger, Anmol Sidhu, Scott Zagorski
  • Technical Paper
  • 2020-01-0175
To be published on 2020-04-14 by SAE International in United States
As part of their ongoing efforts to model and predict vehicle dynamics behavior, the US Army’s Ground Vehicle Systems Center procured a facility in two phases. The facility is called the Suspension Parameter Identification and Evaluation Rig (SPIdER) and has a capacity covering all of the military’s wheeled vehicles, with vehicle weights up to 100,000 lbs (45,400 kg), up to 150 inches wide, with any number of axles. The initial phase had the ability to measure bounce and roll kinematic and compliance properties. The SPIdER is the companion machine to the Vehicle Inertia Parameter Measuring Device (VIPER) which measures the inertia properties of vehicles of similar size. In 2015, the final phase of the SPIdER was completed. This phase includes ground plane wheel pad motion so that lateral, longitudinal, and aligning moment compliance and kinematic properties can be measured. These capabilities greatly enhance the SPIdER’s features, giving it the ability for making complete suspension and steering system kinematic and compliance measurements. Horizontal forces and aligning moments can be applied up to the limits of tire…
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Effect of Flange Radius and Width on the Fatigue Life of Wheel Hub under Cornering Loads

Mahindra & Mahindra Ltd.-Srikrishna Koduri, Durgaprasad Mohapatra, Suhas Kangde
  • Technical Paper
  • 2020-01-1232
To be published on 2020-04-14 by SAE International in United States
Automotive manufacturers are concerned about the safety of its customers. Safety critical components like wheel hub are designed considering the severe loads generated from various customer usage patterns. Accelerated tests, which are derived from Real World Usage Patterns (RWUP), are conducted at vehicle level to ensure the wheel hub meet the durability targets. Load and strain measurement are done to understand the critical lateral loading undergone by the wheel hub. Measured data is synthesized to drive the duty cycle. Finite Element (FE) Analysis of Wheel end is performed at module level considering measured loads to capture the exact load path in physical test. Simulation results are compared with the measured strain for validating the FE analysis procedure. FE analysis was repeated for different wheel hub designs, combinations of different flange radius (R) and flange width (t), to understand the effect of the two critical dimensions on wheel hub durability. Fatigue analysis is done for all wheel hub designs and its life scatter trend is documented. A procedure is established for wheel hub simulation to avoid…
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Automotive Wheel Metamodeling using Response Surface Methodology (RSM) Technique

FCA Engineering India Pvt. Ltd.-Gurumoorthy S, Muthukumar Arunachalam, Sundaravadivelu Mohan
FCA US LLC-Thomas Oery
  • Technical Paper
  • 2020-01-1234
To be published on 2020-04-14 by SAE International in United States
Computational cost plays a major role in the performance of scientific and engineering simulation. This in turn makes the virtual validation process complex and time consuming. In the simulation process, achievement of appropriate level of accurate models as close as physical testing is the root for increase in the computational cost. During preliminary phase of product development, it is difficult to identify the appropriate size, shape and other parameters of the component and they will undergo several modifications in concept and other stages. An approximation model called metamodel or surrogate model has developed for reducing these effects and minimizing the computational cost. Metamodel can be used in the place of actual simulation models. Metamodel can be an algorithm or a mathematical relation representing the relations between input and output parameters. The scope of this paper is to generate approximate models (metamodels) for the automotive wheel with help of response surface methodology (RSM) using Isight commercial tool and to arrive at the optimum shape, size and weight of the wheels by considering all necessary loading conditions.…
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Predication & Correlation of Bearing Preload with Rotational Torque in Wheel End Bearing System

VE Commercial Vehicles, Ltd.-Suchit Sharma, Prasad S. Warwandkar
  • Technical Paper
  • 2020-01-0951
To be published on 2020-04-14 by SAE International in United States
Wheel end bearing is one of the critical components of the vehicle as it shares the loads & support wheel rotation simultaneously. In wheel end, taper roller bearings are used. It helps to withstand both vertical & lateral loads imparted during cornering. Taper roller bearings are used in pair of two so that overall impact of lateral forces during straight running would be nullified. In wheel end bearing systems bearings are kept at distance w.r.t to each other based on position of load line, sharing the total portion of load accordingly. Life of bearings is dependent on whether the bearings are operating in play or preload.This paper focuses on various aspects of bearings life & how it varies with respect to Play & Preload. Also a methodology is developed to measure the overall preload of bearing system.In second stage a methodology is developed which gives an indirect method to measure the bearing preload in terms of wheel end torque to rotate.