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2015-06-15
Technical Paper
2015-01-2193
Masami Matsubara, Daiki Tajiri, Makoto Horiuchi, Shozo Kawamura
Generally as change of vibration characteristics of a tire, natural frequency of a load and rolling tire is lower than that of an unrolling tire. This phenomena is considered to be due to the change of tire stiffness. Early studies described the reason why the change was caused by property of rubber material. One of the evaluation tire stiffness is sidewall stiffness. This stiffness, which have an influence on tire vibration characteristics, is also important design parameter for carry the vehicle body. Tire sidewall is parts of resisting the tension due to inflation pressure. Hence, it is considered that tire sidewall stiffness is decided by tension of inflation pressure and structural dynamic characteristics including property of rubber material. It is necessary to reveal the dynamic characteristic of tire sidewall stiffness. This study describes tire sidewall stiffness as difference of inflation pressure.
2015-06-15
Technical Paper
2015-01-2199
Rui Cao, J Stuart Bolton
Experimental measurements of tire tread band vibration have provided direct evidence that higher order structural-acoustic modes exist in tires, not just the well-known fundamental mode. These modes display both circumferential and radial pressure variations. The theory governing these modes has thus been investigated. A brief recapitulation of the previously-presented coupled tire-acoustical model based on a tensioned membrane approach will be given, and then an improved tire-acoustical model with a ring-like shape will be introduced. In the latter model, the effects of flexural and circumferential stiffness are considered. This improved model accounts for propagating in-plane vibration in addition to the essentially structure-borne flexural wave and the essentially airborne longitudinal wave accounted for in the previous model. The longitudinal structure-borne wave “cuts on” at the tire’s circumferential ring frequency.
2015-06-15
Technical Paper
2015-01-2197
Stijn Vercammen, Fabio Bianciardi, Peter Kindt, Wim Desmet, Paul Sas
In the context of the reduction of traffic-related noise the research reported in this paper contributes to the development of low noise tyres. Two measurement techniques have been analyzed for exterior noise radiation characterization of a loaded rotating slick tyre on a rough road surface. On one hand sound pressure measurements at low spatial resolution with strategically placed microphones on a half-hemisphere around the tyre/road contact point have been performed. This technique provides a robust solution to compute the (overall) sound power level. On the other hand sound intensity measurements at high spatial resolution by means of a scanning intensity probe, LMS Soundbrush, have been performed. This technique allows a more detailed spatial visualization of the noise radiation and helps in getting more insight and better understanding of the acoustical phenomena.
2015-06-15
Technical Paper
2015-01-2198
Masami Matsubara, Nobutaka Tsujiuchi, Takayuki Koizumi, Akihito Ito, Kensuke Bito
Tires of passenger cars greatly influence the performance of NVH (Noise, Vibration and harshness). Especially, it is important to reveal the tire vibration characteristics because there is a strong correlativity between the tire vibration and the interior noise of passenger cars as against road noise, one of the NVH performance. Early studies on the tire vibration characteristics for road noise focused on tire vibration of radial direction, circumferential mode is known, because this mode is dominant in vertical spindle force. However, recent studies of NVH prediction with development, including tires as car substructure, found that not only the circumferential mode, but also the lateral bending mode affect interior noise. Tire vibration mode making noise and vibration problem differs depending on axle vibration direction, and it is demand a comprehensive approach for this problem. This paper presents a new approach for evaluation of natural frequency of tire.
2015-06-15
Technical Paper
2015-01-2264
Rama Subbu, Baskar Anthonysamy, Piyush Mani Sharma
In India, demand for motorcycle with good comfort is increasing among the customers thereby the vibration reduction of two wheelers is key parameter for motorcycle manufacturers. In order to overcome the demand in the market, manufacturers are giving more importance to ride comfort by reducing vibration experienced by the customer while using it. This results in the reduction of the life cycle of the vehicle models and drives the manufacturers to different product design philosophies and design tools, as one would expect. One of the performance factors that continue to challenge designers is that of vehicle longitudinal and vertical acceleration experienced by the motorcycle components. An essential tool in the motorcycle development process is the ability to quantify the durability of the component. This paper main objective is to increase the life of the motorcycle front fender through virtual simulation, on road testing and laboratory testing using NVH tool.
2015-06-15
Technical Paper
2015-01-2355
Luke Fredette, Jason Dreyer
Hydraulic bushings with amplitude sensitive and spectrally varying properties are commonly used in automotive suspension. However, scientific investigation of their dynamic properties has been mostly limited to linear system based theory, which cannot capture the significant amplitude dependence exhibited by the devices. This paper extends prior literature by introducing a nonlinear fluid compliance term for reduced-order bushing models. Quasi-linear models developed from step sine tests on an elastomeric test machine can predict amplitude dependence trends, but offer limited insight into the physics of the system. A bench experiment focusing on the compliance parameter isolated from other system properties yields additional understanding and a more precise characterization. Computational analysis of the bench experiment offers general agreement with both bench experiment and step sine test results.
2015-06-15
Technical Paper
2015-01-2351
Hongyu Shu, Shuang Luo, Li Wang
Recently auto shock absorbers have caused automobile users in China a lot of complaints that they have abnormal noise. In order to measure the noise of auto shock absorbers, a test bench which detect piston-rod vibration response of shock absorber excited by oscillating crankshaft mechanism, and measuring analyzer named as SANTS-Ⅰ,which included specialized signal process and analysis software have been developed. A lot of tests of auto shock absorbers of the abnormal noise have been carried out with the test bench and the piston-rod vibration response data have been collected. It has been showed that there are violent peaks with high frequency in the sine curve of piston-rod oscillating with relative low frequency, signal processed by SANTS-Ⅰmeasuring analyzer.
2015-06-15
Technical Paper
2015-01-2260
Tianze Shi, Shuming Chen, Dengfeng Wang
Artificial intelligence systems are highly accepted as a technology to offer an alternative way to tackle complex and non-linear problems. They can learn from data, and they are able to handle noisy and incomplete data. Once trained, they can perform prediction and generalization at high speed. The aim of the present study is to propose a novel approach utilizing the adaptive neuro-fuzzy inference system (ANFIS) and the fuzzy clustering method for automotive ride performance estimation. This study investigated the relationship between the automotive ride performance and relative parameters including speed, spring stiffness, damper coefficients, ratios of sprung and unsprung mass. A Sugeno fuzzy inference system associated with artificial neuro network was employed. The C-mean fuzzy clustering method was used for grouping the data and identify membership functions. The prediction results were compared with test data of three typical automotives.
2015-06-15
Technical Paper
2015-01-2354
Xiao-Ang Liu, Zhaoping Lv, Wenbin Shangguan
Since the balances of 3-cylinder engine is worse than 4- or 6- cylinder engine, design of powertrain mounting system for engine with three cylinders is much more significant to engine vibration isolation. Inline 3-cylinder engine vibrations are caused by imbalance forces from reciprocate inertial forces of pistons, the rotation inertia forces from the crank and connecting road and the gas combustion forces. The excitation of a 3-cylinder engine is heavier than 3-cylinder engine, so the new design method of mounting system for isolation engine vibration should be developed. The purpose of this paper is to analyze the balance method for 3-cylinder engine, and the optimization method for its mounting system. Firstly the calculation method for obtaining the forces and moments applied to the engine block is presented.
2015-06-15
Technical Paper
2015-01-2269
Lei Zhang, Liangyao Yu, Yonghui Zhang, Xiaoxue Liu, Jian Song
Anti-lock Braking System (ABS) plays an important role in vehicle active safety system. The noise, vibration and harshness (NVH) of hydraulic ABS is influenced mainly by the noise of the hydraulic control unit (HCU) and vibration feedback of braking pedal. Low-level noise makes the driver brake with ease during the anti-lock process. Soft vibration feedback of braking pedal reduces the shock transferred to the driver through the braking pedal. Both reductions of noise and vibration contribute to the driving safety and comfort. By applying the pulse-width modulation (PWM) to the control of high-speed switch valve (HSSV), linear flow control can be realized which may improve the NVH in ABS process significantly. In this paper, the noise source and generating mechanism is investigated during anti-lock process.
2015-06-15
Technical Paper
2015-01-2268
Nilesh Kisanrao Kharate, Sharad S. Chaudhari PhD
Brake squeal is largely accepted by Scientists and technologists as a disturbance which is induced by friction induced vibrations and is frequently occurring at a frequency above 1 kHz. This paper is interested in the finite element analysis (FEA) and experimental modal analysis (EMA) of a commercial disc brake parts. The modal analysis has been used in this work to determine the natural frequency and mode shape pattern. Different four materials of brake disc were tested to predict the natural frequency range which describes its squeal propensity.The destination is to predict the squeal at the former phase of invention using a more realistic model. Firstly, the FE models of the disc brake parts were modeled using 3-D solid element. The experimental modal testing technique known as an impact hammer test has been held away to obtain modal parameters of the disc brake structure. The FE model is validated by comparing experimental results of the brake components.
2015-06-15
Technical Paper
2015-01-2194
Giorgio Bartolozzi, Marco Danti, Guido Nierop, Andrea Camia
Within the automotive industry, a typical way to account for tires in a roadnoise mission simulation is to use the “modal model” supplied by tire manufacturers. Even though this kind of models is certified by the suppliers and is very simple to use, it has the drawback to be disconnected from the physical description of the tire. This reflects in limiting the carmaker company to be able only to request certain modal characteristics to the supplier. The aim of this paper is to present an accurate, yet easy to use, methodology to develop an FE model of a tire, to be used in a full-vehicle simulation. The determined model must be connected to the tire physical properties. These properties are not measured directly, but determined by tuning a properly created geometric FE model to the measured point inertances of the inflated tire. This allows creating the model only by using an optimization algorithm to tune such properties.
2015-06-15
Technical Paper
2015-01-2262
Tom Knechten, Peter Van der Linden, Marius-Cristian Morariu
Structural and vibro-acoustic transfer functions still form an essential part of NVH data in vehicle development programs. Excitation in the three DOFs at all body interface connection locations to target responses gives information on local dynamics stiffness and the body sensitivity for that specific path in an efficient manner. However, vehicles become more compact for fuel efficiency and production costs and to meet the market demand for urban vehicles. Alternative driveline concepts increase the electronic content and new mount locations. To achieve the optimum on road noise NVH, handling performance while conserving interior space and trunk volume requires a complex suspension layout. On top of that, customers put weight on safety and comfort systems which result to a higher packaging density. These trends imply ever limiting accessibility of the interface connections on the body structure.
2015-06-15
Technical Paper
2015-01-2267
Youngha Kim, Choonhyu Kim, Jaewoong Lee, Sunggi Kim
This paper describes structure borne noise reduction process that was using a combination of experimental and analytical methods. First, Major noise paths was identified using experimental Transfer Path Analysis (TPA). Next, FEA-Experimental modeling and forced response simulation were conducted using the Hybrid FEA-Experimental FRF method. Hybrid FEA-Experimental FRF-Based Substructuring (FBS) model was used along with Operational Deflection Shape (ODS) and Modal Analysis. The Hybrid FEA-Experimental model consisted of an experimental FRF representation of the body and a finite element model of sub-frame. The finite element of sub-frame is created by using Altair HyperMesh from CATIA images and dynamic analysis is carried out by using MSC Nastran. The natural frequency and frequency response function of finite element sub-frame model are compared with them of real sub-frame for the validity of applying Hybrid FBS method.
2015-06-15
Technical Paper
2015-01-2266
Andrzej Pietrzyk
Several of the exterior noise sources existing around a vehicle can cause airborne noise issues at relatively low frequencies. One of them is exhaust pipe orifice noise. Traditional methods for handling airborne noise in vehicles, such as SEA, are not suitable for the frequency range of interest. Finite Element analysis has been used, but it often ends up with very heavy runs if semi-infinite acoustic elements are used at the outer boundary as the solution has to be direct instead of modal in this case. There are, however, some softwares that can handle this calculation relatively efficiently. One of the primary choices could be FFT&Actran. However, recently, a similar capability has been developed in MSC Nastran. Also, the calculations involving the free field impedance conditions have been made extremely efficient in CDH/AMLS. Including the poro-elastic material model for foam-based carpets is also becoming practically possible.
2015-06-15
Technical Paper
2015-01-2265
Murali Balasubramanian, Ahmed Shaik
Automotive manufacturers are being challenged to come up with radical solutions to achieve substantial (30-35%) vehicle weight reductions without compromising Safety, Durability, Handling, Aero-thermal or Noise, Vibration and Harshness (NVH) performance. Developing light weight vehicle enablers have assumed foremost priority amongst vehicle engineering teams in order to address the stringent Fuel Economy Performance (FEP) targets while facilitating lower CO2 emissions, downsizing of engines, lower battery capacities etc. Body sheet metal panels have become prime targets for weight reductions via gage reduction, high strength steel replacement, lighter material applications, lightening holes etc. Many of these panel weight reduction solutions are in sharp conflict with NVH performance requirements.
2015-06-15
Technical Paper
2015-01-2364
Xianpai Zeng, Jared Liette, Scott Noll
The vibration isolation effectiveness of powertrain mount configurations is examined for electric vehicle application by focusing on the deteriorating effect introduced by internal mount resonances. Unlike internal combustion engines where mounts are typically designed only for static support and low frequency dynamics, electric motors have higher excitation frequencies in a range where mount resonances often occur. The problem is first analytically formulated by considering a simple 2-dimensional powertrain system. It is shown that by modifying the mount shape, the mount resonance(s) can be shifted while maintaining the same static rate. Further, vibration isolation is improved over a narrow frequency range by using non-identical mounts that split mount resonance peaks. Then a computational model for a realistic drive unit (containing electric motor, power invertor, and differential case) is considered.
2015-06-15
Technical Paper
2015-01-2196
Farokh Kavarana, Scott Fritz, John DeYoung
Recent trends in vehicle light-weighting and tire design requirements have created an increased awareness to tire flat-spotting. Tire flat-spotting occurs when tires remain in a loaded condition without rolling for an extended period of time. Tire flat-spotting can either be temporary or permanent depending on the length of storage and other environmental factors. Tire non-uniformity caused due to flat-spots often induce shake and shimmy (back and forth oscillation of steering wheel) vibration in vehicles due to increased tire-wheel force variation input into the chassis. This can result in increased warranty costs for OEMs (Original Equipment Manufacturers) as well as customer dissatisfaction exhibited in third party quality surveys like the annual J. D. Power IQS (Initial Quality Survey).
2015-06-15
Technical Paper
2015-01-2263
Saeed J. Siavoshani, Prasad Vesikar
The intent of this paper is to summarize a comprehensive test-based approach developed at Siemens to analyze the door closing sound using structural and acoustic loads developed during the event. This study looks into the door closing phenomena from the structural interaction point of view between the door and the body of the vehicle. This method provides the design modification direction to improve the door closing sound and its quality. The study also quantifies the structural and acoustic loads developed at the interface mechanisms at the door-to-body frame interface during the impact event. Considering the transient nature of the door-closing event, a time domain transfer path analysis methodology is used to indirectly quantify the loads being developed between the latch and striker and different faces of door frames and body interfaces. The paper also predicts the equivalent acoustic loads developed at the interfaces between the door frame and the body.
2015-06-15
Technical Paper
2015-01-2353
Jan Bunthoff, Frank Gauterin, Christoph Boehm PhD
In an automotive suspension, the shock absorber plays a significant role to enable the vehicle performances, especially in ride, handling and Noise-Vibration-Harshness (NVH). Understanding its physical characteristics is of great importance, as it has a main influence on the overall vehicle performance. Within this research project simulation models for different passive monotube shock absorber systems have been created in a 1-D system simulation software. The simulation models are designed and parameterized physically. To validate the simulation models measurements on different hydropulse-shaker with specially designed control signals to investigate the response during high frequency excitation, have been done. A detailed discussion of the several models and results of a simulation to measurement comparison is given. After detailed investigation the shock absorber simulation models are now adaptable to the multi body simulation.
2015-05-05
Journal Article
2015-01-9107
Zhiyun Zhang, Miaohua Huang, Meixia Ji, Shuanglong Zhu
Abstract In the field of active safety, the active four-wheel-steering (4WS) system seems to be an attractive alternative and an effective tool to improve the vehicles' handling stability in lane-keeping control performance. Under normal using condition, the vehicle's lateral acceleration is comparatively small, and the mathematic relationship between the small side force excitation and the small slip angle of the tire is in the linear region. Furthermore, the effects of roll, heave, and pitch motions are neglected as well as the dynamic characteristics of the tires and suspension system in this work. Therefore, the linear quadratic control (LQC) theory is used to ensure that the output of the 4WS control system can keep track of the desired yaw rate and zero-sideslip-angle response can also be realized at the same time.
2015-05-01
Journal Article
2015-01-9109
Dzmitry Savitski, Valentin Ivanov, Barys Shyrokau, Jasper De Smet, Johan Theunissen
Anti-lock braking functions of electric vehicles with individual wheel drive can be effectively realized through the operation of in-wheel or on-board motors in the pure regenerative mode or in the blending mode with conventional electro-hydraulic anti-lock braking system (ABS). The regenerative ABS has an advantage in simultaneous improvement of active safety, energy efficiency, and driving comfort. In scope of this topic, the presented work introduces results of experimental investigations on a pure electric ABS installed on an electric powered sport utility vehicle (SUV) test platform with individual switch reluctance on-board electric motors transferring torque to the each wheel through the single-speed gearbox and half-shaft. The study presents test results of the vehicle braking on inhomogeneous low-friction surface for the case of ABS operation with front electric motors.
2015-05-01
Journal Article
2015-01-9141
Selim Oleksowicz, Keith Burnham, Navneesh Phillip, Phil Barber, Eddie Curry, Witold Grzegozek
Hybrid and electric vehicle (H/EV) technology is already well established in the automotive industry and a great majority of car manufacturers offer vehicles with alternative propulsion systems (hybrid or electric - H/E). This advancement, however, does not mean that all technical aspects of H/E propulsion systems have already been encapsulated or even fully understood. This statement is specifically valid for regenerative braking technology. In order to regenerate the maximum possible energy, which may be limited in real applications (e.g. by the charging ratio of the energy storage device(s)), the interaction of regenerative braking and the active driving safety systems (ADSSs) such as the anti-lock braking system (ABS) needs to be taken in to account. For maximum recaptured energy via electric motor (E-Motor) braking, the use of regenerative braking, which generates decelerations greater than 0.1g, should be deployed.
2015-05-01
Journal Article
2015-01-9106
Magnus Löfdahl, Arne Nykänen, Roger Johnsson
Abstract In the automotive industry, tire noise is an important factor for the perceived quality of a product. A useful method to address such NVH problems is to combine recordings with measurements and/or simulations into auralizations. An example of a method to create structure-borne tire noise auralizations is to filter recordings of hub forces and moments through binaural transfer functions experimentally measured from the hub of the car to an artificial head in the car cabin. To create authentic auralizations of structure-borne sound, all six degrees of freedom (DOFs) of hub forces and moments and transfer functions should be included. However, rotational DOFs are often omitted due to measurement difficulty, complexity, time, and cost. The objective was to find which DOF (or DOFs) is perceived as most prominent in structure-borne tire noise. An auralization model of interior structure-borne tire noise was used.
2015-04-14
Collection
This technical paper collection is focused on vehicle dynamics and controls using modeling and simulation, and experimental analysis of passenger cars, heavy trucks, and wheeled military vehicles. The papers address active and passive safety systems to mitigate rollover, yaw instability and braking issues; driving simulators and hardware-in-the-loop systems; suspension kinematics and compliance, steering dynamics, advanced active suspension technologies; and tire force and moment mechanics.
2015-04-14
Collection
Topics of this technical paper collection include (but are not limited to) nonlinear behavior of tires and wheels, static/dynamic stress analysis, nonlinear material modeling, contact stress, impact, noise, vibration, traction, hydroplaning, effect of tires on vehicle performance, rolling resistance, and durability.
2015-04-14
Collection
This technical paper collection provides information on steering and suspension related topics as it applies to ground vehicles. Papers address new approaches as well as advances in application of steering, suspension related technologies.
2015-04-14
Technical Paper
2015-01-1118
Fengyu Liu, Li Chen, Jian Yao, Jianlong Zhang, Chengliang Yin, Dongxu Li, Chunhao Lee, Ying Huang
Abstract Dry dual clutch transmission (DCT) has played an important role in the high performance applications as well as low-cost market sectors in Asia, with a potential as the future mainstream transmission technology due to its high mechanical efficiency and driving comfort. Control system simplification and cost reduction has been critical in making dry DCT more competitive against other transmission technologies. Specifically, DCT clutch actuation system is a key component with a great potential for cost-saving as well as performance improvement. In this paper, a new motor driven clutch actuator with a force-aid lever has been proposed. A spring is added to assist clutch apply that can effectively reduce the motor size and energy consumption. The goal of this paper is to investigate the feasibility of this new clutch actuator, and the force-aid lever actuator's principle, physical structure design, and validation results are discussed in details.
2015-04-14
Technical Paper
2015-01-1117
Yang Liu, Zechang Sun
Abstract Regenerative braking control for a four-wheel-drive (4WD) electric vehicle (EV) equipped with a decoupled electro-hydraulic brake system was studied. The energy flow of the 4WD electric vehicle was analyzed during braking, and the brake force distribution strategy between the front-rear axles, regenerative braking and hydraulic braking was studied. Considering ECE R13 regulations, motors and battery pack characteristic constraints, the optimal regenerative braking control strategy using Genetic Algorithm (GA) was proposed. A Hardware-in-loop (HIL) test was built to verify the proposed regenerative braking control strategy. The results show that the optimal regenerative braking control strategy for the 4WD electric vehicle was advantageous over the comparison program, and regenerative energy efficiency reaches 78.87% under the Shanghai Urban Driving Cycle (SUDC).
2015-04-14
Technical Paper
2015-01-1120
Siddhartha Singh, Sudha Ramaswamy
Abstract 1 The modern engine is capable of producing high torque and horsepower. Now the customer wants state of the art comfort and ergonomics.Thus the manufacturers are focusing on reducing the clutch pedal effort and providing a pleasurable driving experience. In heavy traffic conditions where the clutch is used frequently, the pedal effort required to disengage the clutch should be in comfortable range. Often drivers who drive HCV complain about knee pain which is caused due to high pedal effort, this occurs when ergonomics of ABC (accelerator, brake and clutch) pedals is not designed properly. Thus there is a need to reduce the driving fatigue by optimizing the clutch system. Latest technologies like turbo charging and pressure injection have increased the engine power and torque but have also led to increase the clamp load of clutch. Thus the release load required to disengage the clutch has also increased.
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