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Viewing 1 to 30 of 2182
2017-09-17
Technical Paper
2017-01-2487
Yasuyuki kanehira, Yusuke Aoki, Yukio Nishizawa
Brake squeal is uncomfortable noise that occurs while braking. It is an important issue for automobile quality to prevent brake products from squealing. Brake shims are widely used to reduce squeal occurrence rate. In particular, laminated shims can effectively suppress squeal via the viscoelastic damping of an adhesive layer. However, there are cases where the damping performance at low temperature and the durability performance at high temperature deteriorate. In that regard, we thought of applying frictional damping to shims instead of relying on a temperature-sensitive adhesive layer. To study the application of frictional damping as a new damping mechanism for shims, it is necessary to clarify the characteristics thereof. In order to quantify the damping performance of shims, loss factor has been generally measured with a bending mode tester. However, the influence of friction cannot be evaluated because it is measured under pressure-free condition.
2017-09-17
Technical Paper
2017-01-2486
Kyung Jae Lee
Brake grinding noise is caused by the friction of the disc and pads. The friction generates vibration and it transmits to the body via the chassis system. We calle it structure-borne noise. To improve the noise in the vehicle development, the aspects of chassis or body's countermeasure occurs many problems, cost and time. In this reason many brake company try to make solution with brake system, like brake friction materials or disc surface. However the countermeasure of excitation system also have a lot of risk. It could occur side-effects of braking performance, and need to reverify brake noise like Creep-groan, Groan, Squeal, Judder and so on. In conclusion, It is very important making robust chassis system in initial vehicle development stage. This paper is about rear brake grind noise path analysis and countermeasure of chassis system. There are two steps to analysis. First step is impact hammer test like FRF, MODAL test.
2017-07-10
Technical Paper
2017-28-1926
Jos Frank, Sohin Doshi, Manchi Rao, Prasath Raghavendran
Abstract In today’s automotive scenario, noise vibration and harshness (NVH) has become a synonym for quality perception. This paper evaluates the problem of vibration and noise experienced in M2 category 40 seat bus and suggests the counter measures. Severe vibration is experienced on the bus floor, predominantly towards rear part of the bus. Vibration along with acoustic boom occurs prominently in 4th gear wide open throttle operating condition between 1300-1600 rpm of the engine. This paper focuses on reducing NVH levels by working on the transfer path with little modifications on power-train. Preliminary torsional measurements conducted on powertrain indicated high torsional excitation in the driveline during the problematic rpm zone. Further, Operational Deflection Shape (ODS) analysis revealed that the transfer path to the cabin is rear differential unit and suspension links. The dominant frequencies were identified along the transfer path and suitable modifications were done.
2017-07-10
Technical Paper
2017-28-1985
Hemasunder Banka, Radhika Muluka, Vikram Reddy
Abstract Conventional materials like steel, brass, aluminum etc will fail without any indication, cracks initiation, propagation, will takes place with a short span. Now-a-days to overcome these problem, conventional materials are replaced by hybrid composite material. Not only have this conventional material failed to meet the requirement of high technology applications, like space applications and marine applications and structural applications in order to meet the above requirements new materials are being searched. Hybrid composites materials found to the best alternative with its unique capacity of designing the materials to give required properties and light weight. This paper aims to preparing hybrid composite using artificial fibers. Epoxy as resin and glass fiber as fiber for artificial hybrid composite to make a laminate for preparing leaf spring.
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
2017-01-1890
Xingyu Zhang, Bo Yang, Manchuang Zhang, Sanbao Hu
Abstract H-Bahn ("hanging railway") refers to the suspended, unmanned urban railway transportation system. Through the reasonable platform layout, H-Bahn can be easily integrated into the existing urban transit system. With the development of urban roads, the associated rail facilities can be conveniently disassembled, moved and expanded. The track beam, circuits, communication equipment, and sound insulation screen are all installed in a box-type track beam so that the system can achieve a high level of integration and intelligence. The carriage of the modern H-banh vehicle is connected with the bogies by two hanging devices. The vehicle is always running in the box-type track beam; therefore there are less possibilities of derailment. Consequently, the key work focuses on the running stability evaluation and curve negotiation performance analysis.
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
2017-01-1829
Guillaume Loussert
Abstract The new fuel efficiency and emission standards have forced OEMs to put emphasis on different strategies such as engine downsizing, cylinder deactivation… Unfortunately these new technologies may lead to increased powertrain vibrations generated by the engine and transmitted to the chassis and the car cabin, such that their reduction or elimination has become a key topic for the automotive industry. The use of active engine mounts, acting directly on the fluid of an hydromount, or active vibration dampers, acting as an inertial mass-spring system, are very effective solutions, particularly when using electromagnetic based actuators. Nevertheless, all electromagnetic actuators technologies are not equals and the choice of such actuators must be considered carefully by taking into account the full performances and the overall cost of the solutions.
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
2017-01-1819
Cyril Nerubenko, George Nerubenko
Abstract The problem of crankshaft torsional vibrations for heavy car engines is important for the V8 engines. The paper describes the results of the dynamical study of the new patented Torsional Vibration Dampers mounted on a crankshaft in V8 engines. Design and structure of Torsional Vibration Damper is based on author’s US Patent 7,438,165 having the control system with instantaneous frequencies tuner for all frequencies of running engine. Analysis and disadvantages of conventional rubber and viscous Crank Dampers are shown. The focus of the study is on Torsional Vibration Damper having the mechanical self-tuning structure applicable for V8 engines. Mathematical model based on the system of ordinary differential equations describing the rotation and vibration of mechanical components has been used for the analysis of the dynamic behavior of V8 engine crankshaft system having proposed Torsional Vibration Damper.
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
2017-01-1879
Pranab Saha
Abstract Traditionally, the damping performance of a visco-elastic material is measured using the Oberst bar damping test, where a steel bar is excited using a non-contacting transducer. However, in an effort to reduce the weight of the vehicles, serious effort is put in to change the body panels from steel to aluminum and composite panels in many cases. These panels cannot be excited using a non-contacting transducer, although, in some cases, a very thin steel panel (shim) is glued to the vibrating bar to introduce ferrous properties to the bar so it can be excited. In the off highway vehicles, although the panels are made of steel, they are very thick and are difficult to excite using the Oberst bar test method. This paper discusses a measurement methodology based on mechanical impedance measurements and has the potential to be a viable/alternate test method to the Oberst bar testing. In the impedance method, the test bar is mounted to a shaker at the center (Center Point method).
2017-06-05
Technical Paper
2017-01-1752
Kapil Gupta, Arun Choudhary, Rakesh Bidre
Abstract At present, a Dual Mass Flywheel (DMF) system is widely known to provide benefits on driveline induced noise, vibration and drivability over a Single Mass Flywheel (SMF). A well-tuned DMF provides nice isolation of torsional vibrations generated in periodic combustion process of automobile IC engines. Similarly, a torsional vibration damper mounted on driveline component reduces the torsional excitation and results a lower torsional vibration at driveline components. Noise and vibration issues like boom noise and high vibrations at low engine RPM range drive are often resulted due to high engine firing order torsional excitation input to the driveline. More often, this becomes one of the most objectionable noise and vibration issues in vehicle and should be eliminated or reduced for better NVH performance. A 4 cylinder, 4 stroke small diesel engine equipped with SMF is found to have high engine firing order torsional excitation.
2017-03-28
Technical Paper
2017-01-1480
Zhenfeng Wang, Mingming Dong, Yechen Qin, Feng Zhao, Liang Gu
Abstract The study of controllable suspension properties special in the characteristics of improving ride comfort and road handling is a challenging task for vehicle industry. Currently, since most suspension control requires the observation of unmeasurable state, how to accurately acquire the state of a suspension system attracts more attention. To solve this problem, a novel approach interacting multiple mode Kalman Filter (IMMKF) is proposed in this paper. Suspension system parameters are crucial for the performance of state observers. Uncertain suspension system parameters in various conditions, e.g. due to additional load, have significant effect on state estimation. Simultaneously, state transition among different models may be happened on the condition of varying system parameters.
2017-03-28
Technical Paper
2017-01-1483
Jia Mi, Lin Xu, Sijing Guo, Mohamed A. A. Abdelkareem, Lingshuai Meng
Abstract Systematic research on dynamic model, simulation analyses, prototype production and bench tests have been carried out in recent years on the most popular energy-harvesting shock absorbers-the mechanical motion rectifier (MMR), and the hydraulic-electromagnetic energy-regenerative shock absorber (HESA). This paper presents a novel application of the HESA into bogie system of railway vehicles. In order to study the differences of suspension performance and energy harvesting property between first suspension system and second suspension system of the application, simulation models are built in AMESim to make comparison studies on the different department suspensions caused by the nonlinear damping behaviors of the HESA. The simulation results show that the system can effectively reduce the impact between wheel and rail tracks, while maintaining good potential to recycle vibratory energy.
2017-03-28
Technical Paper
2017-01-1561
Anton A. Tkachev, Nong Zhang
Abstract Rollover prevention is one of the prominent priorities in vehicle safety and handling control. A promising alternative for roll angle cancellation is the active hydraulically interconnected suspension. This paper represents the analytical model of a closed circuit active hydraulically interconnected suspension system followed by the simulation. Passive hydraulically interconnected suspension systems have been widely discussed and studied up to now. This work specifically focuses on the active hydraulically interconnected suspension system. Equations of motion of the system are formalized first. The system consists of two separate subsystems that can be modeled independently and further combined for simulation. One of the two subsystems is 4 degrees of freedom half-car model which simulates vehicle lateral dynamics and vehicle roll angle response to lateral acceleration in particular.
2017-03-28
Technical Paper
2017-01-1562
Junyu Zhou, Chao Liu, Jan Kubenz, Günther Prokop
Abstract This paper describes a new hybrid algorithm for multibody dynamics in vehicle system dynamics which combines the advantages of both embedding technique algorithm and augmented formulation algorithm. An approach to vehicle dynamics modeling based on the hybrid algorithm is presented. Embedding technique algorithm has relatively small number of equations of motion. With help of this technique, an enhanced parametric vehicle dynamics model can be built, representing characteristic curves of suspension comprised in kinematic and compliance. Small number of equations enables the vehicle dynamics model to be simulated very efficiently. In comparison to embedding technique algorithm, the main benefit of augmented formulation algorithm is relatively simple for computer programming. With help of augmented formulation algorithm, the structure of the vehicle dynamic model can be easily extended.
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
2017-01-0348
Mani Shankar, I V N Sri Harsha, K V Sunil, Ramsai Ramachandran
Abstract In an automobile, road loads due to tire-road interaction are transferred to vehicle body through suspension. This makes suspension a critical component from the body durability perspective. During vehicle design and development, optimization of suspension parameters to suit ride and handling performance is a continuous and iterative process. These changes on suspension can affect vehicle body durability performance. This paper tries to establish a process to evaluate the effect of changes in suspension parameters on body durability, thus helping in understanding the impact of these changes. The process starts with virtual model building in Multi Body Dynamics software. The base line model is correlated with testing using fatigue at some critical locations on Body in White (BIW).
2017-03-28
Technical Paper
2017-01-0347
Yat Sheng Kong, Dieter Schramm, M. Zaidi Omar, Sallehuddin Mohd. Haris, Shahrum Abdullah
This paper presents the study of a relationship between objective vertical vibration and coil spring fatigue life under different road excitation to shorten suspension design process. Current development processes of vehicle suspension systems consist of many different stages of analysis and time consuming. Through this vertical vibration and durability characterisation, the vehicle ISO weighted vertical accelerations were used to describe fatigue life of coil spring. Strain signals from various roads were measured using a data acquisition and then converted into acceleration signal. The acceleration signals were then used as input to multibody suspension model for forces time history on spring and acceleration signal of sprung mass extraction. The acceleration signals were then processed for ISO weighted indexes while the force time history was used for coil spring fatigue life prediction respectively.
2017-03-28
Technical Paper
2017-01-0410
Aref M. A. Soliman
Abstract Although active suspension improved vehicle ride comfort, their two main drawbacks are the required high component costs and energy input levels for active suspension. The semi-active and twin accumulator suspensions are proposed which addresses these two drawbacks. Ride performances for passive, twin accumulator and semi-active are examined theoretically using half vehicle model. The power consumed in rolling resistance and power dissipation in suspension for passive, twin accumulator and semi-active suspension systems are evaluated. The effect of road disturbance on the vehicle ride performance for twin accumulator and semi-active suspension systems is studied. The rolling resistance power losses are also investigated. The results showed that the optimum twin accumulator suspension system over all road roughness/speed conditions would have adaptable spring stiffness and damping coefficients which could be changed depending on the road conditions.
2017-03-28
Technical Paper
2017-01-0402
Zhigang Zhang, Shi Xiaohui, Ye Bin
Abstract Based on the formation mechanism of engaging force of clutch, the engagement was divided into four stages: idle stage, cushion spring stage, diaphragm spring stage and locked stage. The mechanism of transmitted torque in each stage was analyzed and the transmitted torque model of clutch was deduced. Multi-load step analysis method based on finite element was used to analyze the coupling load-deformation characteristics of diaphragm spring and cushion spring in engagement, and the change laws of engaging force, diaphragm spring force and release bearing force were achieved and their coupling interaction were studied. And then change of friction coefficient of clutch with oscillating temperature was measured on friction test rig, and effect of temperature on transmitted torque was further discussed. Finally, simulation results of transmitted torque were validated by the experiment. Results indicate that the transmitted torque in clutch engagement has a nonlinear characteristic.
2017-03-28
Technical Paper
2017-01-0430
Bangji Zhang, Kaidong Tian, Wen Hu, Jie Zhang, Nong Zhang
Abstract This paper introduces a vehicle model in CarSim, and replaces a portion of its standard suspension system with an HIS model built in an external software to implement co-simulations. The maneuver we employ to characterize the HIS vehicle is a constant radius method, i.e. observing the vehicle’s steering wheel angle by fixing its cornering radius and gradually increasing its longitudinal speed. The principles of the influence of HIS systems on cornering mainly focus on two factors: lateral load transfer and roll steer effect. The concept of the front lateral load transfer occupancy ratio (FLTOR) is proposed to evaluate the proportions of lateral load transfer at front and rear axles. The relationship between toe and suspension compression is dismissed firstly to demonstrate the effects of lateral load transfer and then introduced to illustrate the effects of roll motion on cornering.
2017-03-28
Technical Paper
2017-01-1494
Weinan Tao, Bingzhao Gao, Hongqing Chu, Mengjian Tian, Hong Chen
Abstract The steer-by-wire system has been widely studied due to many advantages such as good controllability. In the system, the steering column is cancelled and the driver can't feel the feedback torque (also called steering feeling) coming from the ground. Therefore a steering feeling feedback system is needed. In this paper, we propose a simple method to calculate desired feedback torque based on a nonlinear 2DOF vehicle model. The vehicle model contains the nonlinearity of tire. So that the proposed method is also appropriate for big acceleration conditions. Besides that, the properties of steering system such as friction and stiffness are also taken into consideration. As for conventional steering system, driver can only feel part of the feedback torque due to the power assist system. In order to provide steering feeling similar to conventional steering system, a weighting function is proposed to compensate the influence of power assist system.
2017-03-28
Technical Paper
2017-01-1495
Srinivas Kurna, Ruchik Tank, Krishna Srikanth Achanta
1. Abstract At the time of invention of road coaches, the vehicle consisted only of an axle with wheels and a body attached. Smooth roads were built for a better ride comfort however they were not consistent. The road coaches were too bumpy and uncomfortable for the passenger along with the driver who was not able to control the vehicle. That's why the engineers had to shift their attention to the suspension system for a better ride comfort and handling. The technology has advanced with time so as the suspension system. Rubber ended type leaf spring is one of the suspension system types available in the industry. The main function of a suspension in order of importance is as below: 1 Acts as a cushioning device ensuring the comfort of the driver and passengers;2 Maximizes the contact between the tires and the road surface to provide steering stability with good handling;3 Protects the vehicle itself and any cargo or luggage from damage and wear.
2017-03-28
Technical Paper
2017-01-1490
Silvia Faria Iombriller
Abstract The air suspension development and its applications have becoming increasingly relevant for commercial vehicles to provide dynamic ride comfort to driver and reduce the load impact onto driver and or cargo. This paper shows the analysis and application of an air suspension system for commercial tractor vehicles and its dynamic influence. A special focus was given to pneumatic actuation system, responsible for leveling and control of suspension´s stiffness under different conditions of usage, laden and unladed. The project was conducted starting with the vehicle dynamic performance analysis, evaluating the pneumatic suspension circuit modifications in order to obtain vehicle dynamic behavior improvement, ensuring directional stability under different maneuvering conditions.
2017-03-28
Technical Paper
2017-01-1491
Manish Kumar Seth, Jens Glorer, Ralf Schellhaas
Abstract For long automakers around the globe are trying to reduce weight and cost of the components in order to make vehicles more cost and fuel efficient. This paper deals with same problem for rear twist beam for an upcoming vehicle, the task was to reduce the weight and cost of the twist beam structure without compromising on attributes as compared to the surrogate part. This problem was solved by inventing a new torsion profile and gusset combination which uses shape instead of thickness to use material more efficiently thereby reducing weight and cost. This invention has been successfully patented as well.
2017-03-28
Technical Paper
2017-01-1488
Srinivas Kurna, Ruchik Tank, Riddhish Pathak
Abstract The job of a suspension system is to maximize the friction between the tires and the road surface, to provide steering stability with good handling and to act as a cushioning device ensuring the comfort of the driver & passengers. The suspension also protects the vehicle itself and any cargo or luggage from damage and wear. Almost all heavy duty vehicles use inverted type suspension system which is also called as bogie type suspension system. The design of this type of suspension is a complex and difficult science which has evolved over many years. It was recognized very early in the development of suspensions that the interface between vehicle body and wheel needed some sort of cushioning system to reduce the vibration felt as the vehicle moved along. This was already part of road coach design and took the form of leaf (laminated) steel springs mounted on the axles, upon which the vehicle body rested.
2017-03-28
Technical Paper
2017-01-1058
L.V. Pavan Kumar Maddula, Ibrahim Awara
Abstract Increased focus on fuel efficiency and vehicle emissions has led the automotive industry to look into low weight alternative designs for powertrain system components. These new design changes pose challenges to vehicle attributes like NVH, durability, etc. Further, the requirement of high power applications produces even more complexities. The present work explains how a potential design change of half shafts driven by a desire to reduce weight and cost can lead to NVH problems caused by half shaft resonances and explains how using multiple dynamic vibration absorbers can solve the issue to meet customer expectation while improving efficiency. With the aid of Finite Element Analysis (FEA) & optimization software, interactions between multiple DVA’s on a system was understood and optimal damper parameters for effective damping was identified. The final DVA design was tested and verified on the vehicle for optimal attribute performance.
2017-03-28
Technical Paper
2017-01-1284
Khushal Ahmad, Monis Alam
Abstract With the ever increasing number of vehicles on road and the rise of the electric and automated vehicles, it is important to minimize the consumption of energy by each vehicle, regenerative braking is in wide use today, however, the research in the field of regenerative suspension is limited. The regenerative suspension has huge capabilities in power generation especially on third world roads having rather bumpy rides. A huge amounts of energy is wasted in shock absorbers due to friction. This study emphasizes on the implementation of the energy present in the suspension system by replacing the Shock Absorber with a Energy transfer system Involving Hydraulic cylinder, Hydraulic Motor and Dynamo. The energy which is usually lost as heat due to friction in conventional Suspension is used to drive a dynamo through Hydraulic System designed in this paper and electricity is generated.
Viewing 1 to 30 of 2182