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Viewing 1 to 30 of 2528
2010-04-12
Technical Paper
2010-01-0384
Aref M. A. Soliman
This paper deals with an investigation of the road roughness on the vehicle ride comfort using semi-active suspension system. A mathematical model of quarter vehicle for semi active suspension system is developed to evaluate vehicle ride comfort. The rolling resistance and power losses are also investigated. The power consumed in rolling resistance and power dissipation in suspension for passive and semi-active suspensions are evaluated. The obtained results showed that ride comfort increases as the road roughness is decreased. Comparisons between passive and semi-active suspensions systems in terms of ride performance and power dissipation are also discussed.
2010-04-12
Technical Paper
2010-01-0496
Praveen Halepatali, Christopher Ha, Ronald C. Averill
Faced with competitive environments, pressure to lower development costs and aggressive timelines engineers are not only increasingly adopting numerical simulation techniques but are also embracing design optimization schemes to augment their efforts. These techniques not only provide more understanding of the trade-offs but are also capable of proactively guiding the decision making process. However, design optimization and exploration tools have struggled to find complete acceptance and are typically underutilized in many applications; especially in situations where the algorithms have to compete with existing swift decision making processes. In this paper we demonstrate how the type of setup and algorithmic choice can have an influence and make optimization more lucrative in a new product development atmosphere. We also present some results from a design exploration activity, involving linkage and structural development, of an earth moving machine application.
2011-04-12
Technical Paper
2011-01-0269
Adam Bryant, Joseph Beno, Damon Weeks
Battlefield reconnaissance is an integral part of today's integrated battlefield management system. Current reconnaissance technology typically requires land based vehicle systems to observe while stationary or, at best, significantly limits travel speeds while collecting data. By combining current Canadian Light Armored Vehicle based reconnaissance systems with the Center for Electromechanics (CEM) electronically controlled active Electromechanical Suspension System (EMS), opportunities exist to substantially increase cross-country speeds at which useful reconnaissance data may be collected. This report documents a study performed by The University of Texas Center for Electromechanics with funding from L3-ES to use existing modeling and simulation tools to explore potential benefits provided by EMS for reconnaissance on the move.
2011-04-12
Technical Paper
2011-01-0438
Ahmet Kanbolat, Murathan Soner, Tolga Erdogus, Mustafa Karaagac
The parabolic leaf spring plays a vital role in suspension systems, since it has an effect on ride comfort and vehicle dynamics. Primarily, leaf spring endurance must be ensured. Presently, there are two approaches to designing a leaf spring. In the traditional method, fatigue tests should be repeated for each case, considering different material, geometry and suspension hard points. However, it takes a long time and requires a heavy budget to get the optimized solution. In the contemporary method, a numerical approach is used to obtain the fatigue life and the leaf geometry against the environmental condition on the basis of material properties. This paper presents a more precise method based on non-linear finite element solutions by evaluating the effects of the production parameters, the geometrical tolerances and the variations in the characteristics of the material.
2011-04-12
Journal Article
2011-01-0437
Mina M.S. Kaldas, Roman Henze, Ferit Küçükay
Due to the importance of the fast transportation under every circumstance, the transportation process may require a high speed heavy vehicle from time to time, which may turn the transportation process more unsafe. Due to that fact the truck safety during braking and the ride comfort during long distance travelling with high speeds should be improved. Therefore, the aim of this work is to develop a control system which combines the suspension and braking systems. The control system consists of three controllers; the first one for the active suspension system of the truck body and cab, the second one for the ABS and, the third for the integrated control system between the active suspension system and the ABS. The control strategy is also separated into two strategies.
2011-04-12
Journal Article
2011-01-0435
Yan Cui, Thomas Kurfess, Michael Messman
High fidelity mathematical vehicle models that can accurately capture the dynamics of car suspension system are critical in vehicle dynamics studies. System identification techniques can be employed to determine model type, order and parameters. Such techniques are well developed and usually used on linear models. Unfortunately, shock absorbers have nonlinear characteristics that are non-negligible, especially with regard the vehicle's vertical dynamics. In order to effectively employ system identification techniques on a vehicle, a nonlinear mathematical shock absorber model must be developed and then coupled to the linear vehicle model. Such an approach addresses the nonlinear nature of the shock absorber for system identification purposes. This paper presents an approach to integrate the nonlinear shock absorber model into the vehicle model for system identification.
2011-04-12
Journal Article
2011-01-0431
Mina M.S. Kaldas, Kemal Çalışkan, Roman Henze, Ferit Küçükay
Following the developments in controlled suspension system components, the studies on the vertical dynamics analysis of vehicles increased their popularity in recent years. The objective of this study is to develop a semi-active suspension system controller using Adaptive-Fuzzy Logic control theories together with Kalman Filter for state estimation. A quarter vehicle ride dynamics model is constructed and validated through laboratory tests performed on a hydraulic four-poster shaker. A Kalman Filter algorithm is constructed for bounce velocity estimation, and its accuracy is verified through measurements performed with external displacement sensors. The benefit of using adaptive control with Fuzzy-Logic to maintain the optimal performance over a wide range of road inputs is enhanced by the accuracy of Kalman Filter in estimating the controller inputs. A gradient-based optimization algorithm is applied for improving the Fuzzy-Logic controller parameters.
2011-04-12
Technical Paper
2011-01-0430
Aref M. A. Soliman
In this study, LQR control design is presented for the control of a vehicle active suspension system. Seven degrees of freedom, full vehicle model is used. LQR control system is prepared as well as adaptive LQR control system (gain scheduling strategy) to study the effect of each control system using the active suspension on ride performance. The acceleration and dynamic tyre load are evaluated. For the time domain analysis, different road conditions are considered in order to reveal the performance of the two controllers. The simulation results showed that adaptive LQR control system gives a better ride performance compared with LQR control system. Also, the comparison between these control strategies are discussed.
2011-04-12
Technical Paper
2011-01-0429
Mathew Kuttolamadom, Joshua Jones, Laine Mears, John Ziegert, Thomas Kurfess
For incorporating titanium components onto a vehicle in place of existing iron/steel components, there is a need for a methodical procedure to ensure successful and efficient integration. This involves a refinement over standard lightweight engineering procedures. In this paper, a suitable procedure is developed for replacing a structural component with titanium and the method realized. Design and manufacturing issues associated with integrating titanium are identified and addressed. The importance of justifying component replacement in terms of life-cycle costs rather than purely by the manufacturing cost alone is also emphasized.
2010-04-12
Technical Paper
2010-01-1143
Joerg Neubrand, Andreas Lindner, Robert Brandt, Christian Junker
For more than 20 years Mubea strives to develop and produce highly stressed suspension springs and other lightweight automotive steel products. Despite continuous increase of load stress levels of suspension springs it was possible to significantly reduce the weight of suspension springs while increasing robustness. As a successful supplier the company needs to address the continually increasing requirements of the automotive industry for reduced vehicle weight and CO₂ emission through strong efforts in design and process optimization. Targeted now is a weight reduction of another 10% while further enhancing coil spring robustness. In order to achieve these targets Mubea has again optimized the already established High Performance Process (HPP) and has developed a new and innovative method of designing coil springs. To optimize coil spring design customized Finite Element (FE) software was developed and successfully implemented.
2010-04-12
Journal Article
2010-01-0639
M. Gobbi, P. Guarneri, G. Mastinu, G. Rocca, L. Castignani
The paper presents a method for the indoor testing of road vehicle suspension systems. A suspension is positioned on a rotating drum which is located in the Laboratory for the Safety of Transport at Politecnico di Milano. Special six-axis load cells have been designed and used for measuring the forces/moments acting at each suspension-chassis joints. The forces/moments, wheel accelerations, displacements are measured up to 100 Hz. Two different types of test can be performed. The tire/wheel unbalance effect on the suspension system behavior (Vibration and Harshness, VH) has been analyzed by testing the suspension system from zero to the vehicle maximum speed on a flat surface and by monitoring the forces transmitted to the chassis. In the second kind of test, the suspension system has been excited as the wheel passes over different cleats fixed on the drum.
2010-04-12
Technical Paper
2010-01-0723
Xiaobin Ning, Bin Meng, Jisheng Shen, Xizhuang Dong, Xiaolin Zi, Jie Zhang
Chassis platform is usually supplied for several types of cars which have their individual requirement for handling stability and ride comfort. Therefore the stiffness, damping and the dimension of the guide mechanism of the suspension have to be adjusted to meet the different performance requirements of different styles of cars. In this paper a module exclusively used for handling stability analysis of chassis platform is developed based on ADAMS/Car. With this module chassis engineers can easily adjust the parameters of suspension such as stiffness, damping and locations of hard points to match the front and rear suspension suitably and then predict and optimize the performance of the suspension system. Therefore different types of cars that using chassis platform can fulfill their own handling stability and ride comfort requirements.
2011-04-12
Technical Paper
2011-01-0182
Sujay J. Kawale, John B. Ferris
The accuracy of computer-based ground vehicle durability and ride quality simulations depends on accurate representation of road surface topology as vehicle excitation data since most of the excitation exerted on a vehicle as it traverses terrain is provided by the terrain topology. It is currently not efficient to obtain accurate terrain profile data of sufficient length to simulate the vehicle being driven over long distances. Hence, durability and ride quality evaluations of a vehicle depend mostly on data collected from physical tests. Such tests are both time consuming and expensive, and can only be performed near the end of a vehicle's design cycle. This paper covers the development of a methodology to synthesize terrain profile data based on the statistical analysis of physically measured terrain profile data.
2011-04-12
Technical Paper
2011-01-0090
Wei Liu, Wenku Shi Sr
In this paper, a Magneto-Rheological (MR) fluid semi-active suspension system was tested on a commercial vehicle, a domestic light bus, to determine the performance improvements compared to passive suspensions. MR fluid is a material that responds to an applied magnetic field with a significant change in its rheological behavior. When the magnetic field is applied, the properties of such a fluid can change from a free-flowing, low viscosity fluid to a near solid, and this change in properties takes place in a few milliseconds and is fully reversible. A quarter suspension test rig was built out to test the nonlinear performance of MR damper. Based on a large number of experimental data, a phenomenological model of MR damper based on the Bouc-Wen hysteresis model was adopted to predict both the force-displacement behavior and the complex nonlinear force-velocity response.
2011-04-12
Journal Article
2011-01-0058
Giles Bryer, Christopher Eccles
As mass reduction becomes an increasingly important enabler for fuel economy improvement, having a robust structural development process that can comprehend Vehicle Dynamics-specific requirements is correspondingly important. There is a correlation between the stiffness of the body structure and the performance of the vehicle when evaluated for ride and handling. However, an unconstrained approach to body stiffening will result in an overly-massive body structure. In this paper, the authors employ loads generated from simulation of quasi-static and dynamic vehicle events in ADAMS, and exercise structural finite element models to recover displacements and deflected shapes. In doing so, a quantitative basis for considering structural vehicle dynamics requirements can be established early in the design/development process.
2013-05-13
Technical Paper
2013-01-1975
Xingyu Liang
This paper presents a method to identify the radiation noise source of diesel engine based on a Cepstrum Analysis (CA) and Analytic Hierarchy Process (AHP). Through measuring noise and surface vibrations of a diesel engine, cepstrum analysis is applied to the measured signals. In an investigation of the radiation noise source, the hierarchy tree and judgment matrix are given. Through identification, the main noise source is found. The results show that the left body contributes maximally to non-harmonic spectral characteristics of noise. Therefore, in order to reduce engine vibration and noise effectively, we should optimize and improve left body. In addition, optimizing and improving gear chamber casing, oil pan, inlet pan and valve chamber cover can decrease harmonic vibration and noise of engine.
2013-04-08
Journal Article
2013-01-1357
W. Bradley Cwycyshyn, Joseph Fedullo
With deflected-disc dampers, digressive force-velocity shapes are achieved via the combined effects of disc stack stiffness and hub-offset. The degree of digressiveness can be adjusted to alter vehicle performance by changing the proportion of these parameters. Optimizing this relationship can yield substantial vehicle performance improvements, but the time consuming iterative process of developing a new disc stack for each hub-offset discourages experimentation. To enable more efficient digressiveness comparisons, a regression-based computational method has been developed which converts disc stack stiffness from one hub-offset to other offsets directly, without iteration. Once an initial disc stack for one offset has been tuned by traditional methods, stacks for other offsets can be calculated that maintain overall damper control.
2013-09-24
Technical Paper
2013-01-2382
Venkatesh Narayanan, Karalmarx R, Sai Sankaranarayana, Kalyankumar Hatti
The Bogie suspensions ensure better stability at higher loads and also give the utmost reliability under extreme climatic conditions with minimum maintenance. Many vehicle manufactures have adopted for the bogie suspension at rear based on its advantages. The noises generated from the vehicle in the field includes engine noises and flow noises and hence it is very difficult to clearly discern the noise generated from suspension system of the vehicle [1]. Most suspension system noises do not come from a single part but they are caused by the coupling action between related parts, making it difficult to clearly identify the exact cases. This paper details the overall approach to identify the bogie suspension noise on a commercial vehicle and countermeasures to reduce the same.
2004-03-08
Technical Paper
2004-01-0341
Hermann Steffan, Andreas Moser
Due to the increasing number of minivans and sport utility vehicles, rollovers have become more significant. As a result, various accident reconstruction programs have been developed to address this issue. To reconstruct rollover crashes, various requirements have to be fulfilled. These consist of: providing a simple method that is able to model three dimensional environments that often play a major role in rollovers. including suspension, tire and collision models must be provided. This is particularily important in the rollover initiation phase. including proper vehicle geometry and contact stiffness must be available. These are important for simulation of body contacts that affect the vehicle motion. This study focuses on one program, PC-CRASH. This program was developed to allow simulations of vehicle 3-dimensional movements before, during and after the impact. The study also discusses the physical background of the models, their capabilities as well as their limitations.
2004-03-08
Technical Paper
2004-01-0425
Santi Udomkesmalee, Dominik Utama, Michael Nicolls
The Formula SAE (FSAE) racing event is an annual collegiate competition in which student-designed and built, open-cockpit racecars are examined and evaluated via a variety of static and dynamic events. Cornell University has been involved in the competition since 1987, and was the first team to run its own custom-built engine control module (ECM) in 1993. This paper presents the evolution of the Cornell ECM and offers a systems-level overview of the design of the third-generation Cornell ECM 2003 (ECM03) system. The ECM03 was used in the 2003 Cornell FSAE racecar, the ARG03.
2004-03-08
Technical Paper
2004-01-1553
Shinichi Nishizawa, Jason Logsdon, Maiko Ikeda, Tom Sugiyama, Isao Otani, Naoshi Sato, Akihiko Kumagai, Joseph Harralson, Paul Hozian, Toshio Hamano
Today's suspension coil spring design requires not only accounting for one-dimensional force along the coil spring axis, but also exerting a complex multi-dimensional force and torque field between the spring seats [1,2,3,4,5]. This paper describes the design of a 6-DOF parallel mechanism to mimic the force and torque characteristics of a coil spring. This mechanism can physically generate the 6-DOF force and torque field of a coil spring, allowing designers to experimentally evaluate the quasi-static force effects of a coil spring while still at the design stage. Examples are presented for a physically generated force and torque field of a coil spring used in a McPherson Strut suspension, and its effect is correlated to the side force acting upon the suspension strut. As an extension, this mechanism can be widely used to investigate the relationship between spring characteristics and damper friction.
2004-03-08
Technical Paper
2004-01-1548
X. Fan, H. Cai, S. Lin, L. N. B. Gummadi, K. Cao
Stabilizer bars in a suspension system are supported with bushings by a frame structure. To prevent the axial movement of the stabilizer bar within the bushing, several new stabilizer bar-bushing systems have been developed. The new systems introduce permanent compressive force between the bar and the bushing thereby preventing the relative movement of the bar within the bushing. This mechanical bond between the bar and the bushing can eliminate features such as grippy flats, collars etc. In addition, by controlling the compression parameters, the properties of the bushing such as bushing rates can be tuned and hence can be used to improve the ride and handling performance of the vehicle. In this paper, nonlinear CAE tools are used to evaluate one such compressively loaded bushing system. Computational difficulties associated with modeling such a system are discussed.
2004-03-08
Technical Paper
2004-01-1547
Ramesh Edara, Shan Shih
Multibody Dynamics Simulation (MDS) studies are valuable in providing guidance in suspension systems design and reduce product development cost and time. These studies are used in various stages of suspension system design and development. In both concept study and detailed design the subsystem kinematics, dynamics and full vehicle dynamics studies are used. In this paper, four case studies for suspension system performance optimization using MDS studies are presented.
2004-03-08
Technical Paper
2004-01-1557
Asghar Ramezani, Shahram Shahriari
In this paper, the governing equations on the progressive rate coil springs are derived and implemented as a software package. The spring is divided to conical elements and deformation of each element under gradually increasing load is determined, based on which the spring shape under an arbitrary load is extracted. Gradual load increase results in deactivation of the coils, which causes the stiffness variation. The stress calculations and fatigue life cycle estimation is performed based on SAE recommendations. The results are verified using FEM analysis and experiments.
2004-03-08
Technical Paper
2004-01-1582
Richard Romano, Steven Schultz
The United States Research, Development, and Engineering Command's Tank Automotive Research, Development and Engineering Center (U.S. Army RDECOM-TARDEC) laboratories, in accordance with a Science and Technology Objective (STO), are looking for both real-time and non real-time modeling and simulation methods to advance the capabilities and methodologies used in the Army's Modeling and Simulation areas. Advancing technologies require TARDEC to model new components and vehicles that may be significantly different from prior systems. TARDEC's ultimate goal is to develop the capability to model and accurately recreate the behaviors of advance technologies that may present themselves in the Army's Transformation and its Future Combat System (FCS) of vehicles in real-time with the soldier-in-the-loop. This paper discusses TARDEC's effort to accomplish this goal.
2004-03-08
Technical Paper
2004-01-1389
Liyun Zheng, Jeremy Plenzler
Vane type cam phasers have been widely used in internal combustion engines to vary valve timing to achieve purposes such as low emissions, greater torque, and higher horsepower. One of the primary concerns in using a vane phaser is its position holding ability when disturbances are present. Disturbances include cam torque oscillation, cam pulley speed fluctuation, oil pressure fluctuation, and engine acceleration or deceleration. Cam torque disturbance is the biggest contributor to phaser position error. This paper will first present the generic schematic of a variable cam phasing system and its challenges, followed by the characterization of the fluid dynamics of the vane phaser, with an emphasis on the effects of pressure, leakage, and oil aeration on the vane phaser fluid dynamics and its ability to reject cam torque disturbance.
2004-03-08
Technical Paper
2004-01-1226
Xiaoyong Lu, Das Ramnath, Chin-Yuan Perng
In this paper we describe the development and application of a CAE methodology to investigate stresses incurred in the torque converter anti-rattle spring subjected to various static and dynamic loading conditions. The objectives of this study are three-fold. First, develop and demonstrate a dynamic modeling methodology suitable for torque converter rattle analysis. Second, provide insight into the underlying physics in the hardware design and identify key parameters to achieve high-mileage improvement, and third, recommend feasible design and manufacturing parameters for design improvements. Anti-rattle springs have been widely used in torque converter clutch to reduce rattle noise between the spline interface of the cover plate and the piston plate. They are constantly subjected to static and dynamic stresses under various vehicle operation conditions.
2004-03-08
Technical Paper
2004-01-0776
Jounghum Yoon, Kyoungtae Kye
Under driving condition, vehicles undergo various kinds of load, which consequently induces the fracture of automotive suspension system component. Not only to prevent these fractures but also to cut down cost and weight, it is important to predict load conditions and stresses at an early design stage. This paper covers the abuse condition that means extreme load condition such as pothole and curb strike. In this simulation, the limit behavior of car is considered, including non-linearity and large displacement of suspension system, and the method for simulating these events is described as an exemplary application using ADAMS.
2004-03-08
Technical Paper
2004-01-0787
Yuseorg Jeong, Cheehwan Jang
The topology optimization(1) made a great success in pure structural design in various industrial fields: Automobile, Air Craft, Military Vehicle and so on which made structure stiffer or increase of fundamental mode on the basis of limited resource or amount of materials. However, the optimization has been highly oriented in the filed of linear system and single objective function in itself though, in reality, it is necessary to introduce multi-disciplinary optimization due to higher needs of customers and better performance. However, since various factors interact each other in actual engineering fields in highly complicated manner, to the best of author's knowledge, it has not been achieved successfully so far.
2004-03-08
Technical Paper
2004-01-0782
Gary Leevy, Khoa Cao
The fundamentals of multi-leaf spring design as determined through beam theory offers a general perspective on how finite element analysis works. Additionally, the fundamentals of combining dissimilar materials require a basic knowledge of how the combined equivalent modulus affects the overall stiffness characteristics of multi-leaf design. By capturing these basic fundamentals into finite element modeling, an analysis of a steel-composite multi-leaf contact model relative to an idealized steel-composite multi-leaf model shows the importance of contact modeling. The results demonstrate the important differences between an idealized non-contact model relative to a complete contact model.
Viewing 1 to 30 of 2528

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