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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 vibration in vehicles due to increased tire-wheel force variation input into the chassis. This can result in increased warranty costs for OEMs as well as customer dissatisfaction exhibited in third party quality surveys like the annual J. D. Power IQS. While tire flat-spotting can occur during vehicle shipping process, it is particularly of concern for slow moving vehicle inventory that remains at manufacturing plants and/or dealership parking lots for extended periods of time.
2015-06-15
Technical Paper
2015-01-2195
Youichi Kamiyama
Tire cavity noise has long been one of the main road noise issues, as it is close to a pure tone and produces reverberations, which makes it an unpleasant noise for vehicle occupants. Various ideas for devices to reduce tire cavity noise have been patented or discussed in technical reports, but many issues remain for commercialization, and at present only some tires have appeared as products. Therefore, technology was developed for mounting Helmholtz resonators on the wheels, enabling reduction of tire cavity noise without placing restrictions on the tires. The advantage of this technology is that the cost and productivity targets needed for mass production can be satisfied without impairing the tire and wheel functions.
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
2015-01-2194
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
2015-01-2199
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
2015-01-2267
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
2015-01-2263
Saeed Siavoshani
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
2015-01-2261
Joseph Plattenburg, Jason Dreyer, Rajendra Singh
Combined active and passive damping is an emerging trend as it should be an effective solution to challenging NVH problems, especially for lightweight vehicle components that demand advanced noise and vibration treatments. Compact patches are of particular interest due to their small size and cost; however, improved modeling techniques are needed for such methods. This paper presents a refined modeling procedure for side-by-side active and passive damping patches applied to thin, plate-like powertrain casing structures. As an example, a plate with fixed boundaries is modeled as this is representative of real-life transmission covers which often require damping treatments. Further scientific studies include a bench experiment that determines frequency dependent properties of the viscoelastic damping material. The proposed model is then utilized to examine several cases of active and passive patch location, and vibration reduction is determined in terms of insertion loss for each case.
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
2015-01-2262
Tom Knechten, Peter Van der Linden
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
2015-01-2355
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
2015-01-2353
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 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 hydropuls-shaker with specially designed control signals to investigate the behaviour 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.
2015-06-15
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
2015-01-2265
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
2015-01-2260
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
2015-01-2266
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
2015-01-2354
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.
2015-04-14
Technical Paper
2015-01-1417
Jeffrey Muttart
An analysis was performed utilizing the results from seven emergency steering studies and four routine lane change studies. Closed course and naturalistic research were included. These studies showed that in a routine lane change, Drivers reached peak lateral acceleration approximately one-second after steering after which lateral acceleration decreases linearly. These results were consistent with those from forward and backing acceleration research published elsewhere. Though, when drivers steered in response to an emergency situation, again, peak lateral acceleration occurred near one-second after steering onset, but average lateral acceleration decreased non-linearly. This non-linear decrease between onset of steering and completion of the maneuver was indicative of counter-steering, or reduced subsequent steering (straightening). The results show that the average lateral acceleration could be modeled with a power function.
2015-04-14
Technical Paper
2015-01-1345
Srinivas Kurna, Arpit Mathur, Sandeep Sharma
In commercial vehicle, Leaf Spring design is an important milestone during product design and development. Leaf springs are the most popular designs having multiple leaves in contact with each other and show hysteresis behavior when loaded and unloaded. Commonly used methods for evaluation of leaf spring strength like endurance trials on field and Rig testing are time consuming and costly. On the other hand, virtual testing methods for strength and stiffness evaluation give useful information early in the design cycle and save considerable time and cost. They give flexibility to evaluate multiple design options and accommodate any design change early in development cycle. A study has been done in VECV to correlate rig result with FEA simulation result of Multi-stage Suspension Leaf Spring, entirely through Finite Element Analysis route. Virtual leaf spring with U-Clamps and Suspension brackets with revolute joints are modeled in FEA which is similar to rig test bed setup.
2015-04-14
Technical Paper
2015-01-1464
Qiang Chen, Miao Lin, Bing Dai, Jiguang Chen
The objective of this work was to describe typical accident scenarios for pedestrian accidents in China. The accident analysis aims to develop test procedures for assessing Autonomous Emergency Braking (AEB) systems. Beyond that, this study was also with the goal of estimating the effectiveness of potential reduction of fatally and severely injured pedestrians by AEB systems.Based on statistics, more than 25% of traffic fatalities were pedestrians in China. Autonomous Emergency Braking (AEB) systems are already penetrating the vehicle market and are designed to offer protection against the occurrence and severity of collisions. However there is a need to evaluate the systems and their effectiveness. Test methods for such active safety systems are being developed and will be implemented in NCAP tests in the near future, e.g. 2016 in Euro-NCAP, and most probably in 2018 C-NCAP tests (still in consulting phase).
2015-04-14
Technical Paper
2015-01-1572
L. Daniel Metz, J. Sneddon
Deteriorated roadway surfaces (potholes) encountered under everyday driving conditions produce external vehicle disturbance inputs that are potentially destabilizing and highly transient. We examine vehicle behavior in response to such inputs through simulation. Idealized pothole geometrical configurations are used to represent common deteriorated roadway surfaces, and as environments in the HVE simulation suite of programs. Differences in vehicle behavior are catalogued and the potential for destabilized vehicle behavior is examined, particularly under conditions in which only one side of the vehicle contacts the pothole. Vehicle types employed in the simulations consist of a sedan, sports car and SUV. Results show that many combinations of speed, vehicle type and pothole configuration have significant destabilizing effects on vehicles.
2015-04-14
Technical Paper
2015-01-1497
Hideaki Shibue, Devesh Srivastava
Torsion beam suspensions are lightweight and low-cost, and they are therefore frequently used for the rear of small front-wheel drive vehicles. The configuration of the suspension is simple and it comparatively consists of fewer components. However, it is difficult to predict their characteristics and satisfy the target of the performance in the early stages of development in particular, because it should realize the various performance elements demanded of a suspension in a single part. A great deal of research has been conducted on the cross-sectional shape of the beam section, but up to the present there has been almost no discussion of the effect of property of the trailing arms on suspension characteristics. This paper discusses tests conducted to study the effect of the rigidity of the trailing arms, and considers the mechanism of that effect.
2015-04-14
Technical Paper
2015-01-1499
Tadatsugu Takada, Kazuki Tomioka
Honda developed the right and left independent toe-angle control system (first-generation P-AWS) in the Acura RLX in 2013 and announced it as the first in the world. As indicated in a previous paper, “Independent Left and Right Rear Toe Control System,” with this system Honda has realized an excellent balance between the fun of handling that is at the driver’s will (INOMAMA) and driving performance with a sense of stability. This first-generation P-AWS is designed to be optimal to the vehicle specifications (suspension axial force, steering gear ratio, etc.) of the Acura RLX. Honda is due to widely adapt P-AWS to other models from now on. Following this, we developed the next-generation P-AWS system (second-generation P-AWS) in order to reconcile system performance and low cost wherever possible, in order to be adaptable for all ACURA models.
2015-04-14
Technical Paper
2015-01-1495
Qiushi Wang, Shenjin Zhu, Yuping He
Articulated heavy vehicles (AHVs) exhibit poor directional performance that is attributed to the high accident rate of these vehicles. Many control strategies have been proposed to increase the safety of AHVs. Optimal controllers based on the Linear Quadratic Regulator (LQR) technique have been explored to enhance the lateral stability of AHVs; these controllers are designed under the assumption that the vehicle model parameters and operating conditions are given and they remain as constants. However, in reality, the vehicle system parameters and operating conditions may vary. For example, the payload of trailer may vary within a huge range. To address the vehicle model parametric variation issue, this paper proposes a model reference adaptive controller for active trailer steering of AHVs. The adaptive controller is designed based on a tractor-semitrailer model with three degrees of freedom; to ensure the convergence of the controller, Lyapunov theory is applied.
2015-04-14
Technical Paper
2015-01-1510
Edoardo Sabbioni, Davide Ivone, Francesco Braghin, Federico Cheli
Estimation of friction coefficient and sideslip angle represents a key-point for improving control systems for vehicle safety, e.g. ESP (Electronic Stability Control), VDC (Vehicle Dynamics Control), etc. A model-based approach (state observer or Kalman filter) is generally used on purpose. Benefits induced by in-tyre sensors on sideslip angle and friction coefficient estimation are investigated in this paper. Thus tyre cornering force measurements are added to the ones usually present on-board vehicle (steer angle, lateral acceleration and yaw rate) and used to implement an Extended Kalman Filter (EKF) based on a single-track vehicle model. Tyre-road contact forces are assumed to be provided once per wheel turn by a smart tyre constituted of two tri-axial accelerometers glued on the tyre inner liner. Performance of the proposed observer is evaluated on a series of handling maneuvers and its robustness to road bank angle and tyre/vehicle parameters variation is discussed.
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