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Viewing 91 to 120 of 8253
2017-06-05
Technical Paper
2017-01-1901
Christian Glandier, Stefanie Grollius
Abstract This paper presents the application to full vehicle finite element simulation of a steady state rolling tire/wheel/cavity finite element model developed in previous work and validated at the subsystem level. Its originality consists in presenting validation results not only for a wheel on a test bench, but for a full vehicle on the road. The excitation is based on measured road data. Two methods are considered: enforced displacement on the patch centerline and enforced displacement on a 2D patch mesh. Finally the importance of taking the rotation of the tire into account is highlighted. Numerical results and test track measurements are compared in the 20-300 Hz frequency range showing good agreement for wheel hub vibration as well as for acoustic pressure at the occupant’s ears.
2017-06-05
Technical Paper
2017-01-1804
Chulwoo Jung, Hyeon Seok Kim, Hyuckjin Oh, Kwang Hyeon Hwang, Hun Park
Abstract An efficient method to determine optimal bushing stiffness for improving noise and vibration of passenger cars is developed. In general, a passenger vehicle includes various bushings to connect body and chassis systems. These bushings control forces transferred between the systems. Noise and vibration of a vehicle are mainly caused by the forces from powertrain (engine and transmission) and road excitation. If bushings transfer less force to the body, levels of noise and vibration will be decreased. In order to manage the forces, bushing stiffness plays an important role. Therefore, it is required to properly design bushing stiffness when developing passenger vehicles. In the development process of a vehicle, bushing stiffness is decided in the early stage (before the test of an actual vehicle) and it is not validated until the test is performed.
2017-06-05
Technical Paper
2017-01-1836
Fangfang Wang, Peter Johnson, Hugh Davies, Bronson Du
Abstract Whole-body vibration (WBV) is associated with several adverse health and safety outcomes including low-back pain (LBP) and driver fatigue. The objective of this study was to evaluate the efficacy of three commercially-available air-suspension truck seats for reducing truck drivers’ exposures to WBV. Seventeen truck drivers operating over a standardized route were recruited for this study and three commercially-available air suspension seats were evaluated. The predominant, z-axis average weighted vibration (Aw) and Vibration Dose Values (VDV) were calculated and normalized to represent eight hours of truck operation. In addition, the Seat Effective Amplitude Transmissibility (SEAT), the ratio of the seat-measured vibration divided by the floor-measured vibration, was compared across the three seats. One seat had significantly higher on-road WBV exposures whereas there were no differences across seats in off-road WBV exposures.
2017-06-05
Technical Paper
2017-01-1851
Taewook Yoo, Ronald W. Gerdes, Seungkyu Lee, Daniel Stanley, Thomas Herdtle, Georg Eichhorn
Abstract Several methods for evaluating damping material performance are commonly used, such as Oberst beam test, power injection method and the long bar test. Among these test methods, the Oberst beam test method has been widely used in the automotive industry and elsewhere as a standard method, allowing for slight bar dimension differences. However, questions have arisen as to whether Oberst test results reflect real applications. Therefore, the long bar test method has been introduced and used in the aerospace industry for some time. In addition to the larger size bar in the long bar test, there are a few differences between Oberst (cantilever) and long bar test (center-driven) methods. In this paper, the differences between Oberst and long bar test methods were explored both experimentally and numerically using finite element analysis plus an analytical method. Furthermore, guidelines for a long bar test method are provided.
2017-06-05
Technical Paper
2017-01-1855
Ramakanta Routaray
Abstract The basic function of a motorcycle frame is somewhat similar to that of the skeleton in the human body, i.e. to hold together the different parts in one rigid structure. One of the major benefits (for a motorcycle enthusiast) of using an advanced frame design lies in the sporty handling characteristics of the bike. A well designed frame can add to the joy of riding a motorcycle as the bike would feel more stable, effortless, and confident around corners, in straight lines and while braking. A well approved modeling [2] techniques or adequate guide line principles have to be followed while designing the body and chassis in order to achieve the vibration within control. This paper depicts a methodological right approach (guide lines) while designing the body and chassis of a two wheeler in order to control noise and vibration of the body and chassis.
2017-06-05
Technical Paper
2017-01-1857
Joshua R. Goossens, William Mars, Guy Smith, Paul Heil, Scott Braddock, Jeanette Pilarski
Abstract Fatigue life prediction of elastomer NVH suspension products has become an operating norm for OEMs and suppliers during the product quoting process and subsequent technical reviews. This paper reviews a critical plane analysis based fatigue simulation methodology for a front lower control arm. Filled natural rubber behaviors were measured and defined for the analysis, including: stress-strain, fatigue crack growth, strain crystallization, fatigue threshold and initial crack precursor size. A series of four distinct single and dual axis bench durability tests were derived from OEM block cycle specifications, and run to end-of-life as determined via a stiffness loss criterion. The tested parts were then sectioned in order to compare developed failure modes with predicted locations of crack initiation. In all cases, failure mode was accurately predicted by the simulation, and predicted fatigue life preceded actual end-of-life by not more than a factor of 1.4 in life.
2017-06-05
Technical Paper
2017-01-1900
Leiaixin Yang, Yinong Li, Peiran Ding, Parsa Zamankhan, John G. Cherng
Abstract Brake squeal is an instability issue with many parameters. This study attempts to assess the effect of thermal load on brake squeal behavior through finite element computation. The research can be divided into two parts. The first step is to analyze the thermal conditions of a brake assembly based on ANSYS Fluent. Modeling of transient temperature and thermal-structural analysis are then used in coupled thermal-mechanical analysis using complex eigenvalue methods in ANSYS Mechanical to determine the deformation and the stress established in both the disk and the pad. Thus, the influence of thermal load may be observed when using finite element methods for prediction of brake squeal propensity. A detailed finite element model of a commercial brake disc was developed and verified by experimental modal analysis and structure free-free modal analysis.
2017-06-05
Journal Article
2017-01-1902
Guan Qiao, Geng Liu, Zhenghong Shi, Yawen Wang, Shangjun Ma, Teik Lim
Abstract Actuator and roller screw mechanism are key components of electromechanical brake (EMB) system in automotive and aerospace industry. The inverted planetary roller screw mechanism (IPRSM) is particularly competitive due to its high load-carrying capacity and small assembly size. For such systems, friction characteristic and friction torque generated from rolling/sliding contacts can be an important factor that affects the dynamic performance as well as vibration behavior. This paper investigates the modeling and simulation of the EMB system in early design stage with special attention to friction torque modelling of IPRSM. Firstly, a step-by-step system model development is established, which includes the controller, servo motor, planetary gear train and roller screw mechanism to describe the dynamic behavior of the EMB system.
2017-06-05
Technical Paper
2017-01-1903
Masami Matsubara, Nobutaka Tsujiuchi, Tomohiko Ise, Shozo Kawamura
Abstract The tire is one of the most important parts, which influence the noise, vibration, and harshness of the passenger cars. It is well known that effect of rotation influences tire vibration characteristics, and earlier studies presented formulas of tire vibration behavior. However, there are no studies of tire vibration including lateral vibration on effect of rotation. In this paper, we present new formulas of tire vibration on effect of rotation using a three-dimensional flexible ring model. The model consists of the cylindrical ring represents the tread and the springs represent the sidewall stiffness. The equation of motion of lateral, longitudinal, and radial vibration on the tread are derived based on the assumption of inextensional deformation. Many of the associated numerical parameters are identified from experimental tests.
2017-06-05
Technical Paper
2017-01-1755
Frank C. Valeri, James T. Lagodzinski, Scott M. Reilly, John P. Miller
Abstract Hybrid powertrain vehicles inherently create discontinuous sounds during operation. The discontinuous noise created from the electrical motors during transition states are undesirable since they can create tones that do not correlate with the dynamics of the vehicle. The audible level of these motor whines and discontinuous tones can be reduced via common noise abatement techniques or reducing the amount of regeneration braking. One electronic solution which does not affect mass or fuel economy is Masking Sound Enhancement (MSE). MSE is an algorithm that uses the infotainment system to mask the naturally occurring discontinuous hybrid drive unit and driveline tones. MSE enables a variety of benefits, such as more aggressive regenerative braking strategies which yield higher levels of fuel economy and results in a more pleasing interior vehicle powertrain sound. This paper will discuss the techniques and signals used to implement MSE in a hybrid powertrain equipped vehicle.
2017-06-05
Technical Paper
2017-01-1805
Krzysztof Prażnowski, Jaroslaw Mamala
Abstract The vibrations of the sprung mass of a passenger car, traveling along a road surface, are random. They also form its main source but there are besides other factors to consider. The resulting force ratio is overlapped by other phenomena occurring at the interface of the pneumatic tire with the road surface, such as non-uniformity of tires, shape deformations and imbalances. The resulting additional inertia force acts on the kinematic force that was previously induced on the car body. The vibrations of the sprung mass of the car body at the time can be considered as a potential source of diagnostic information, but getting insight their direct identification is difficult. Moreover, the basic identification is complicated because of the forces induced due to the random interference from road roughness. In such a case, the ratio defined as SNR assumes negative values.
2017-05-30
Technical Paper
2017-01-5002
James Bradley Skarie
Abstract Antilock braking systems (ABS) are inherently limited by the static coefficient of friction (µ) between a vehicle’s tires and the road surface. This paper explores a unique active safety concept, Integrated Coefficient Enhancement (ICE), which works to improve ABS well beyond their present limits. The ICE concept was developed using a basic physics principle: to change µ between two surfaces, at least one of the surfaces must be altered in some way. By quickly deploying a specially designed tractive medium (TM) to aid in directional stability and braking, hazardous situations can be greatly mitigated. This paper describes the features and testing results of this TM and its aerodynamic-mechanical-electronic deployment apparatus. Under all slippery road conditions tested, the developed TM mitigated skidding, with improvements that ranged from 20% to several hundred percent, depending on conditions and deployment rates.
2017-05-24
Technical Paper
2017-36-0006
Claudio Jr. Ferreto, Ademir S. Carvalho, Robson D. A. Abreu, Pedro F. Marinho, Luiz R. Guimarães
Abstract Brake noise causes discomfort to passengers and a perception of reduced vehicle quality. Other types of vehicle noises have been significantly reduced and consequently brake noise and vibration are becoming more perceivable by owners, leading to high warranty costs. It is known in the Brake Industry that the natural frequencies of brake rotors may have a significant participation in disc brake squeal generation, and, a robust process control of this characteristic in the manufacturing gives an important contribution to reduce brake noise. However, recent studies have demonstrated a significant variation of natural frequencies due to manufacturing and this is the outcome of carbon equivalent content in gray cast iron. This paper is concerned with the understanding of this phenomenon and its influence on disc brake noise generation. For this research, it was manufactured two batches of this rotor from two different grades of carbon equivalent.
2017-05-24
Technical Paper
2017-36-0007
Luiz Roberto Guimarães, Robson Demétrius Araújo Abreu, Ademir Carvalho, Claudio Jr. Ferreto
Abstract The improvement of motor’s power requires consequently the improvement in brake system also. The kinetic energy of moving vehicles is transformed in a big part of heat, but there is a part that can be transformed in vibration and sound pressure. One of these vibration and sound pressure complain is known as howl noise. The howl noise complain is very intense and uncomfortable for passengers and pedestrians. Today, the customers spend a lot of money in his vehicles comfort and this disorder can’t occur. This paper presents a methodology which uses Experimental Modal Analysis (EMA) and Operational Modal Analysis (OMA) to survey the dynamic behavior of suspension and brake systems at the howl noise occurrence condition.
2017-05-24
Technical Paper
2017-36-0004
Wesley Bolognesi Prado, Silvia Faria Iombriller, Jonathan Orsi Chiu, Alexandre Roman
Abstract S-cam brakes concept are largely used by commercial vehicles around the world due to its low cost, easy maintenance and robustness. An important component of s-cam brakes is the slack adjuster, that is responsible for amplify brake chamber forces and assure correct lining and drum clearance. Therefore usually slack adjuster mechanism characteristics are defined only by empiric method considering trial and error tentative. This paper aims to demonstrate a methodology created to develop new air s-cam brakes slack adjuster definition taken in consideration its interface with other brake components. During this study was identified design specification for each component and its influence on adjustment process. It was verified the intrinsic characteristics of slack adjuster mechanism and developed a calculation tool to predict its actuation on the brake. The interface of slack adjuster with other foundation brake components and drum compliance were also studied.
2017-05-24
Technical Paper
2017-36-0005
Diego Severo Antunes, Diego Masotti
Abstract Analytical models used to design most of drum brake systems assume rigid body behavior of shoes and drum, resulting in sinusoidal pressure distribution in the friction interface. This approach leads to various limitations and sometimes incoherent results at typical applications since brake components are highly deformable and the contact pressure distribution plays an important role on the brake system efficiency. This study addresses a numerical analysis of drum brake pressure distribution, using Finite Element Method and considering shoes and drum as flexible bodies. The model validation from experimental procedure, where brake components were instrumented in an inertial dynamometer test. Once the pressure distribution can not be accurately measured, this research uses strain field measurements to calibrate the numerical model. This model is nonlinear, implying in convergence difficulties.
2017-05-24
Technical Paper
2017-36-0001
Luís Fernando Nuss de Souza, Antônio Carlos de Oliveira, Narã Vieira Vetter
Abstract After the anti-skid brake system (ABS) introduction, mandatory for all vehicles in the Brazilian market, manufacturers have given increasing attention to optimized systems which meet legal and safety requirements. For commercial vehicles, an alternative for the ABS, which presents feasibility, is the configuration 4S/3M (4 wheel-speed sensors and 3 modulator valves) in substitution to the configuration 4S/4M. In other words, application of just one modulator valve to control the brakes of the same axle, front or rear, instead of independent control per each brake of the vehicle. The aim of this paper is to present a performance comparison between a brake system fitted with ABS configuration 4S/3M and an ABS configuration 4S/4M. To this end, both configurations were tested on the same vehicle application in accordance with the Brazilian legislation, CONTRAN 519/15.
2017-05-24
Technical Paper
2017-36-0003
Rafael Paini Pavlak, Patric Daniel Neis, Jean Carlos Poletto, Liu Yesukai de Barros, Ney Francisco Ferreira
Abstract The current study presents some testing procedures which have been designed for friction and noise measurements of brake friction materials using a laboratory-scale tribometer. The uncertainties (errors) and precision of the measurements are also described in this paper. Some case studies related to friction, wear and noise related issues in brake friction materials were chosen to show the respective testing procedures. Through the error study, it was shown that the uncertainties of the lab. test bench are mainly associated with 3 variables: torque, force and sliding radius. The combined uncertainty of the friction measurements is less than or equal to ±1%, considering the typical operating range of the machine. The possibility of using two samples from a single brake pad also contributes to the reliability of the machine test and procedures.
2017-05-24
Technical Paper
2017-36-0020
Luiz Filipe de Medeiros Gomes, Fernanda de Lima Menezes, Ademir de Silva Carvalho, Claudio Junior Ferreto, Luciano Matozo
Abstract The brake system is one of the most important safety systems of the vehicle. So far, several researches are being conducted with the objective of improve its efficiency. In a disc brake, it is the friction between the pads and the rotor the responsible for kinetic energy conversion into heat and brake torque generation. Demanding brake applications, can generate high temperatures levels which can reduce the friction coefficient between pads and rotor, reducing brake efficiency. Thus, the present work aims to evaluate the front disc temperature drop by the installation of a duct on the vehicle frontal bumper to direct the outside air into the wheelhouse This duct has the function to direct the outside air towards to the brake disc. Theoretical studies, Computational Fluid Dynamics (CFD) simulations and experimental dynamometer tests were carried out.
2017-05-24
Technical Paper
2017-36-0015
Alexis Klauber Chaia Kléperon, Robson Demétrius Araújo Abreu, Rômulo Morais Bitencourt, Francis José Marochi Almeida
Abstract The vibroacoustic comfort sense inside vehicles is a topic of major concern in current automotive industry. Moreover, the increase in demand of users and the competition in the automotive sector lead automakers to invest in developing more comfortable vehicles. Thus, even noises in specific usage scenarios and short time is claimed. This paper raises the cause and proposes solutions to a noise from the brake system known as "Moan Noise". This noise happens under specific conditions of use, but is easily identified by the user. Moreover, it is a random phenomenon and difficult to characterize. Thus, this study shows a methodology to survey the phenomenon under study and validation of proposals for improvement through operational techniques and experimental modal analysis.
2017-05-24
Technical Paper
2017-36-0021
Jean Cory de Souza Silva, Juan Carlos Horta Gutierrez
Abstract This work consists in a study about regulations for brake system in Brazil, which aims to show the current scenario, as well as the evolution of the resolutions and technologies. Within the last few years Brazil had a considerable evolution in terms of safety requirements for brake systems. In 2009 an important step was taken when Brazilian Traffic National Consil (Conselho Nacional de Trânsito - CONTRAN), the agency responsible for traffic regulations in Brazil, emitted the resolution N° 312, which established the mandatory use of Anti-lock Brake System (ABS). This obligatoriness was introduced gradually, beginning by passengers cars in 2010, when 8% of the automobiles manufactured in that year should have the system installed as standard item. This percentage would increase until reaching 100% of vehicle production in 2014.
2017-05-24
Technical Paper
2017-36-0016
Mathias Haag, Achim Reich, Angelo Sardá, Michael Wurmlinger-Georg, Martin Semsch, Leonardo Felix Borim
Abstract Residual brake torque (RBT) is generated in disc brakes as a result of contact between brake disc and brake pads when the braking pressure is not applied. Among the negative implications of RBT are, notably, dispensable additional fuel consumption as well as increased pad (taper) wear. Several properties of the brake system have a direct influence on the level of residual torque [1]. A major effect is connected to the caliper properties determining the clearance gap. This is characterized by the default air gap between pads and disc and its distribution regarding vehicle inner and outer sides (piston and fist sides for floating type calipers). Initial air gap is mainly influenced by the sealing grove design (between piston and housing, where the sealing ring is positioned). The retraction of the piston due to the sealing ring, also called rollback, mainly depends on the load case (e.g. applied pressure and temperature).
2017-05-24
Technical Paper
2017-36-0010
André G. L. Suetti, Carlos Eduardo Correia
Abstract The knowledge of the elastic properties of friction materials is especially important in the development of brake systems. The stiffness of the system directly impacts on the consumption of the fluid during braking and the user interaction with the brake pedal, in addition to being strongly linked to the occurrence or not of certain types of noise. For the analysis of brake pad stiffness, is well known the compressibility equipment, which evaluates the deformation subject to a load in the axial direction. The first stage of the work proves that the compressive deformation of the pad has a non-linear behaviour as a function of the applied force. Based on this non-linearity, tests are carried out on 93 brake pads, where trends between the instantaneous deformation and the final compressibility result are sought.
2017-05-24
Technical Paper
2017-36-0011
J. Ocampo, S. Jelic, J. Han
Abstract Thermal performance of a brake system is one of the key attributes in a new vehicle development process. Adequate brake cooling characteristics are part of the vehicle performance and safety requirements. The design of a new brake system, however, can be a complex task from a thermal engineering perspective, particularly because of complex interactions between the brake component and the rest of the vehicle. Frequently, the vehicle integration issues are the most serious challenges for brake engineers. There are considerations on how much heat should be dissipated from a single and/or consecutive braking events vs. how much cooling can be provided to the brake corner. Design issues such as where to direct the cooling air to how much flexibility is allowed while complying with other requirements from the studio and aero teams. For a brake engineer, the priority is to maximize cooling to the brake corner and prevent system failure.
2017-04-11
Journal Article
2017-01-9177
N. Obuli Karthikeyan, R. Dinesh Kumar, V. Srinivasa Chandra, Vela Murali
Abstract In the modern automotive sector, durability and reliability are the most common terms. Customers are expecting a highly reliable product but at low cost. Any product that fails within its useful life leads to customer dissatisfaction and affects the reputation of the OEM. To eradicate this, all automotive components undergo stringent validation protocol, either in proving ground or in lab. This paper details on developing an accelerated lab test methodology for steering gearbox bracket using fatigue damage and reliability correlation by simulating field failure. Initially, potential failure causes for steering gearbox bracket were analyzed. Road load data was then acquired at proving ground and customer site to evaluate the cumulative fatigue damage on the steering gearbox bracket. To simulate the field failure, lab test facility was developed, reproducing similar boundary conditions as in vehicle.
2017-03-28
Technical Paper
2017-01-1466
Claudia De La Torre, Ravi Tangirala, Michael Guerrero, Andreas Sprick
Abstract Studies in the EU and the USA found higher deformation and occupant injuries in frontal crashes when the vehicle was loaded outboard (frontal crashes with a small overlap). Due to that, in 2012 the IIHS began to evaluate the small overlap front crashworthiness in order to solve this problem.A set of small overlap tests were carried out at IDIADA’s (Institute of Applied Automotive Research ) passive safety laboratory and the importance of identifying the forces applied in each structural element involved in small overlap crash were determined. One of the most important structural elements in the small overlap test is the wheel. Its interaction in a small overlap crash can modify the vehicle interaction at the crash, which at the laboratory the interaction is with a barrier. That interaction has a big influence at the vehicle development and design strategy.
2017-03-28
Technical Paper
2017-01-1727
Yumin Lin, Bo-Chiuan Chen, Hsien-Chi Tsai, Bi-Cheng Luan
Abstract A model-based sensor fault detection algorithm is proposed in this paper to detect and isolate the faulty sensor. Wheel speeds are validated using the wheel speed deviations before being employed to check the sensor measurements of the vehicle dynamics. Kinematic models are employed to estimate yaw rate, lateral acceleration, and steering wheel angle. A Kalman filter based on a point mass model is employed to estimate longitudinal speed and acceleration. The estimated vehicle dynamics and sensor measurements are used to calculate the residuals. Adaptive threshold values are employed to identify the abnormal increments of residuals. Recursive least square method is used to design the coefficients of the expressions for adaptive threshold values, such that the false alarms caused by model uncertainties can be prevented. Different combinations of estimations are employed to obtain 18 residuals.
2017-03-28
Technical Paper
2017-01-1509
L. Daniel Metz
Abstract We examine the characteristics, properties and potential idealized delamination failure modes of tires in this work. Calculations regarding tire failure stresses during tire failure scenarios, as well as during normal operation, are made. The calculations, though idealized, indicate that large chassis loads can result from the idealized failures.
2017-03-28
Technical Paper
2017-01-1371
Hao Pan, Xuexun Guo, Xiaofei Pei, Xingzhi Dong
Abstract Brake pedal feel plays an important role in the driver's comprehensive subjective feeling when braking, which directly affects the active safety and riding comfort of passenger car. A systematical mathematical model of the vehicle brake system is built in according with the structure and system characteristics of hydraulic servo brake system. A complete hydraulic servo brake system simulation model composed of brake pedal, vacuum booster, brake master cylinder, brake pipe, brake wheel cylinders, brake calipers is established in AMESim. The effects of rubber reaction plate stiffness, rubber valve opening, brake master cylinder piston, brake caliper, brake pipe deformation and friction liner deformation on brake pedal feel are considered in this model. The accuracy of this model is verified by real road vehicle tests under static and dynamic two different conditions.
2017-03-28
Technical Paper
2017-01-0436
Tianjun Zhu, Bin Li
Abstract A new extended planar model for multi-axle articulated vehicle with nonlinear tire model is presented. This nonlinear multi-axle articulated vehicle model is specifically intended for improving the model performance in operating regimes where tire lateral force is near the point of saturation, and it has the potential to extend the specific axles model to any representative configuration of articulated vehicle model. At the same time, the extended nonlinear vehicle model can reduce the model's sensitivity to the tire cornering coefficients. Firstly, a nonlinear tire model is used in conjunction with the 6-axle planar articulated vehicle model to extend the ranges of the original linear model into the nonlinear regimes of operation. Secondly, the performance analysis of proposed nonlinear vehicle model is verified through the double lane change maneuver on different road adhesion coefficients using TruckSim software.
Viewing 91 to 120 of 8253