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Viewing 1 to 30 of 462
2011-04-12
Journal Article
2011-01-0162
Ming Jiang, Huaizhu Wu, Kebing Tang, Minsuk Kim, Sivapalan Senthooran, Heinz Friz, Yingzhe Zhang
The engineering process in the development of commercial vehicles is facing more and more stringent emission regulations while at the same time the market demands for better performance but with lower fuel consumption. The optimization of aerodynamic performance for reduced drag is a key element for achieving related performance targets. Closely related to aerodynamics are wind noise and cabin soiling and both of them are becoming more and more important as a quality criterion in many markets. This paper describes the aerodynamic and aero-acoustic performance evaluation of a Dongfeng heavy truck using digital simulation based on a LBM approach. It includes a study for improving drag within the design of a facelift of the truck. A soiling analysis is performed for each aerodynamic result by calculating the accumulation of particles emitted form the wheels on the cabin. One of the challenges in the development process of trucks is that different cabin types have to be designed.
2013-09-24
Technical Paper
2013-01-2368
Harish Harinarayanan
Commercial vehicle payload depends on the client for which the vehicle fleet owner is operating. Load carriers like flatbed trailer offer the flexibility to be loaded with a large number of light payloads or a few numbers of massive payloads. Such load carriers have to be evaluated for various possibilities of loading patterns that could happen in the market. The objective of this work is to evaluate flatbed trailer for its structural strength for different customer application cases, using computer simulation. Structural load cases due to payloads like containers, steel coils and cement bags are arrived at. Static structural analysis using MSC Nastran is performed to evaluate for the worst customer loading pattern from structural stress point of view. This paper also describes a simplified method for simulating the effect of trailer suspension, tractor suspension and the fifth-wheel coupling in the analysis whose detailed modeling is not possible at the concept level.
2004-03-08
Technical Paper
2004-01-1207
Terry D. Day
SIMON is a new 3-dimensional vehicle dynamic simulation model. The capabilities of the model include non-linear handling maneuvers and collision simulation for one or more vehicles. As a new model, SIMON must be validated by comparison against actual handling and collision experiments. This paper provided that comparison. Included in the validation were lane-change maneuvers, alternate ramp traversals, limit maneuvers with combined braking and steering, vehicle-to-vehicle crash tests and articulated vehicle handling tests. Comparison against other models were included. No metric was provided for handling test comparisons. However, statistical analysis of the collision test results revealed the average path range error was 6.2 to 14.8 percent. The average heading error was -4.7 to 0.7 percent. Delta-V error was -1.6 to 7.5 percent. VEHICLE SIMULATION has many uses in the vehicle design and safety industries.
2004-10-26
Technical Paper
2004-01-2673
Jean-Claude Ossyra, Monika Ivantysynova
A new control concept was developed to minimize the power losses of a hydrostatic drive line for off-road vehicles. The drive line control concept is based on two separate closed loop controls, one for the hydrostatic transmission and another for the combustion engine. The command values for both control loops are calculated under consideration of the characteristic curves of the combustion engine and the losses within the hydrostatic transmission, using an on-line optimization procedure. This paper discusses the benefits of this control concept based on a comparison of typical realistic driving manoeuvres. Objective of the investigations for different output powers is the potential of fuel savings under different operating conditions. A hardware-in-the-loop test rig for the investigated hydrostatic propel drive is used for the experimental validation.
2004-10-26
Technical Paper
2004-01-2714
Katrin Strandemar, Boris Thorvald
This paper presents the ride diagram, a new way of evaluating and presenting ride comfort Furthermore, a simplified methodology is suggested to test and correlate objective measures of vehicle ride with subjective driver impressions. The ride diagram is calculated from measured cab accelerations resulting from increased levels of excitation. The basic idea is to graphically visualize how ride comfort changes with excitation. Test drivers are then asked to pair the set of tested vehicles with corresponding curves in the ride diagram. This step assures that the selected measure captures how drivers apprehend changes in vehicle ride. The suggested methodology is illustrated on trucks with different cab suspension settings. For a given test track increased vehicle speed is used to increase the excitation level. The trucks are also placed in a road simulator to enable easy variation of both excitation type and level.
2004-10-26
Technical Paper
2004-01-2694
Stefano J. Cassara, David C. Anderson, J. Magnus Olofsson
The accurate prediction of commercial-vehicle ride and handling performance with computer simulation tools is dependent on the level of correlation between the computer model and experimental data. Correlating vehicle attributes to physical test data is often challenging due to the large number of degrees of freedom - and, correspondingly, the large number of tunable parameters - typically required to accurately model vehicle behavior. A high level of interaction between input parameters and vehicle attributes further complicates the task. As a result, this type of correlation is a multi-objective optimization exercise in which the judicious planning of supporting test activity is critical to achieving the right level of model accuracy with an acceptable amount of resource investment. This paper discusses the methodology implemented in the validation of a tractor-semitrailer ADAMS model for both ride and handling simulations and presents the results obtained.
2004-10-26
Technical Paper
2004-01-2667
Timothy J. Milburn
Product development and manufacturing organizations are moving from the traditional, multiple and serial design-build-test cycle approach to an integrated, concurrent task and systems engineering paradigm, led by upfront planning, analysis and simulation, supported by credible product test data. This “paradigm shift” includes a move from a predominance of physical testing for product prototype validation to simulation-led problem solving and performance validation, using Computer Aided Engineering, and Design (CAE and CAD) tools. Supported by use of Computer Aided Testing (CAT), physical testing capabilities have comparably grown in accuracy and application range. The role of testing is moving from mostly pre-production validation to include support of product design decisions throughout the development process, including upfront planning.
1999-11-15
Technical Paper
1999-01-3705
Thomas D. Gillespie, Michael W. Sayers
The use of computer simulation of vehicle dynamics as a development tool has come into its own over the past few decades. “Simulated” testing on a computer makes possible a degree of control and repeatability that allows the automotive engineer to determine the influence of design variables on different aspects of dynamic performance in ways that would be difficult or impossible by experimental methods. One of the software tools receiving wide acceptance for simulating trucks and combination vehicles is Truck-Sim™. The attraction of this program arises in part from its foundation of truck modeling methods developed at the University of Michigan Transportation Research Institute over the past two decades, and the use of an advanced graphical user interface to make the software both easy to understand and easy to use by design and development engineers.
1999-11-15
Technical Paper
1999-01-3778
Thomas Spoerl, Charles Nesser
Electronic Control Unit (ECU) networks should be tested as a system to ensure efficient and accurate results. Often, testing of ECU networks is performed with specially equipped test vehicles. In–vehicle testing is particularly costly, time–consuming, and inefficient with heavy–duty trucks. Also, complete code coverage is typically not achieved with in–vehicle testing. This incomplete testing can lead to numerous problems including an increase in warranty costs and the failure to meet regulatory requirements. A scalable Hardware–in–the–Loop (HiL) system can provide a means to test such large ECU networks in a laboratory environment.
1999-11-15
Technical Paper
1999-01-3737
R. Happee, J. Loczi
Both RAMSIS and MADYMO are widely applied for computer aided vehicle design. Both programs are used to simulate occupant-vehicle interactions where RAMSIS focuses on ergonomics in normal driving conditions and MADYMO focuses on passive safety in impact conditions. This paper describes simulations of human seat interactions using RAMSIS and MADYMO. An interface has been developed to convert RAMSIS human models and postures to MADYMO. Static seat interaction was first simulated using RAMSIS. This provided an estimated posture and a qualitative assessment of comfort. Then the posture as estimated by RAMSIS was analyzed in MADYMO. The seat was modeled in MADYMO as an arbitrary surface, and the combined surface compliance of seat and human tissues was defined in terms of stress versus penetration. The MADYMO analysis of the posture estimated by RAMSIS provided for instance joint loads, seat contact pressures and seat friction.
1999-11-15
Technical Paper
1999-01-3734
A. Costa Neto, L.C. Ferraro, V.L. Veissid, C.A.M. Freitas, M.A. Argentino, O.T. Perseguim, R.R. Ripoli
The present work describes the modeling and analysis processes of a medium sized truck manufactured in Brazil with regard to comfort behavior. The vehicle model includes Hotchkiss suspensions front and rear with shackle and with a double stage with bump stops at the rear. It is also included frame flexibility in ADAMS in an approximate manner based on a Finite Element Analysis of the frame. Nonlinear shock absorber curves are also represented for the vehicle and cab suspensions. Viscoelastic bushings for cab and powertrain suspension are also included. Random track profile is generated as input and vehicle comfort is described in terms of the ISO 2631-85 Standard. The effect on vehicle comfort of changing a design parameter can be predicted in the model and verified experimentally.
1999-11-15
Technical Paper
1999-01-3707
Mark A. Bennett, William P. Amato
The accuracy of existing rotational wheel dynamics models has been found to be insufficient for heavy vehicle Antilock Braking System (ABS) and Electropneumatic Braking System (EBS) simulation, specifically when wheelspeeds are at or near zero but the vehicle speed is not. Control strategies specific to ABS and EBS, the low frequency response of pneumatic actuation, and the practice of using fewer modulators than braked wheels require that a vehicle model be able to handle lockedwheel scenarios accurately. Commercially available models have been found unsatisfactory in this regard, and technical literature has not been found to address this issue.
2011-01-19
Technical Paper
2011-26-0048
Aymeric Rousseau, Ram Vijayagopal
Other than in Japan, medium and heavy duty vehicles (MHDVs) are not regulated despite accounting for a significant portion of the fuel consumed (about 26% in the US in 2008). Government agencies worldwide are currently evaluating options to address that issue. Due to the large number of vehicle applications, some of them being “one of a kind”, vehicle modelling and simulation offers an attractive solution to medium and heavy duty regulations. This paper discusses the advantages and challenges of vehicle simulation to support regulations.
2011-01-19
Technical Paper
2011-26-0092
Vikas Yadav, Gerardo Olivares
Public transportation system and specifically transit bus systems are key element of the national transportation network in United States. Buses are one of the safest forms of transportation. Nonetheless, bus crashes resulting in operator injuries and fatalities do occur. According to National Transportation Statistics from 1990-2002, the number of transit motor buses in the U.S. has increased by 30% [1]. The majority of fatal crashes involving transit buses result from frontal crashes which could be fatal for bus operators. Therefore, crashworthiness research is a continuing effort. Research has been performed to analyze and improve the safety of transit bus operators. This paper describes the design, analysis and testing of an inflatable restraint system for a bus operator. At present a three point restraint is the only safety feature implemented on transit buses. The primary objective was to study the level of safety provided by the present safety system.
2010-10-06
Technical Paper
2010-36-0264
Alaor J. Vieira Neto, Claudio G. Fernandes, Rafael Pedroso, Eduardo Vianna
In order to improve the product development efficiency, nowadays, the usage of simulation tools has become almost mandatory. The number of different settings, tested during the suspension tuning, for example, can grow reasonably in the same amount of time. Such a situation would be impossible experimentally. In this context, this work presents a truck model carried out in a multi-body environment (Adams) in order to evaluate aspects of vehicle ride comfort. The model was created with all project information available. Typical tracks, used for ride subjective evaluation, are modeled as track profiles and added to the multi-body model. The model is then validated against experimental data. The measurement setup used as well as the test conditions are fully detailed, as well as the comparison of the data acquire with the simulation results. Once with the validated model, it can be explored in order to extract all information required for a robust project.
2012-05-16
Technical Paper
2012-36-0020
Vinicius de Almeida Lima, Leandro Garbin, Carlos Rodrigues dos Santos Neto
Due to the practice of lifting the rear suspension of heavy trucks, adopted by some end-users in Brazil, and in order to supply theoretical propositions to the manufacturers of suspension components for product improvement, this work describes stability and lateral dynamics tests simulations of a 4×2 rigid truck with 15000 kg of gross vehicle weight (GVW) and with changes in its originals leaf springs, predicting its dynamics responses in cornering and safety against rollover when unloaded and loaded at its GVWR limit.
2012-05-16
Technical Paper
2012-36-0018
Andre Carneiro Couto Alvarez, Everton Corte, Leandro Garbin, Vinicius de Almeida Lima
This paper discusses the benefits of truck simulation for ride and handling tuning at product development. Virtual simulation can guide the conception of new vehicles to a better "first guess" of dynamics characteristics, providing calibrated options to define parameters for springs, dampers and anti-roll bars, closer to the desired condition. TruckSim™, from Mechanical Simulation, was the chosen software due to its user-friendly interface, fast modeling and post-processing that matches with challenging product time-to-market. The scope of analysis is to evaluate/compare virtual results against subjective/objective tests on real prototypes, in order to proof software correlativity. The first step was to develop the vehicle model, using 3D CAD models information, data acquired from real prototypes and product specifications. The chosen vehicle was a 9-ton 4X2 rigid truck.
2016-04-05
Technical Paper
2016-01-0571
Guillaume Bernard, Mark Scaife, Amit Bhave, David Ooi, Julian Dizy
Abstract Internal combustion (IC) engines that meet Tier 4 Final emissions standards comprise of multiple engine operation and control parameters that are essential to achieve the low levels of NOx and soot emissions. Given the numerous degrees of freedom and the tight cost/time constraints related to the test bench, application of virtual engineering to IC engine development and emissions reduction programmes is increasingly gaining interest. In particular, system level simulations that account for multiple cycle simulations, incylinder turbulence, and chemical kinetics enable the analysis of combustion characteristics and emissions, i.e. beyond the conventional scope of focusing on engine performance only. Such a physico-chemical model can then be used to develop Electronic Control Unit in order to optimise the powertrain control strategy and/or the engine design parameters.
2015-01-14
Technical Paper
2015-26-0036
Marina Roche, Marco Mammetti
Abstract The running costs of heavy-duty trucks are strongly influenced by fuel consumption. Even a small improvement in fuel economy has a big effect on fleet cost savings and pollutant contamination. From the different possible sub-systems to be improved, reducing the rolling resistance of the tires is a cost-effective option due to its relatively high influence on the fuel consumption without negatively affecting the overall performance. Nevertheless, the other causes of resistance forces, such as mechanical friction and aerodynamics must be optimized as well. The focus of the work is to propose an accurate methodology specifically for heavy trucks for the proper evaluation of resistance forces to allow accurate fuel consumption simulation. For this purpose, the results obtained in proving ground were post-processed by applying different resistance forces characterization methodologies and the results were analyzed theoretically and numerically.
2016-04-05
Technical Paper
2016-01-0474
Shukai Yang, Bingwu Lu, Zuokui Sun, Yingjie Liu, Hangsheng Hou
Abstract A low frequency vibration issue around 3.2 Hz occurs during a commercial heavy truck program development process, and it is linked to extremely uncomfortable driving and riding experiences. This work focuses on an analytical effort to resolve the issue by first building a full vehicle MBS (multi-body-system) model, and then carrying out vibration response analyses. The model validation is performed by using full vehicle testing in terms of structural modes and frequency response characteristics. In order to resolve the issue which is excited by tire non-uniformity, the influence of the cab suspension, frame modes, front leaf spring system and rear tandem suspension is analyzed. The root cause of the issue is found to be the poor isolation of the rear tandem suspension system. The analytical optimization effort establishes the resolution measure for the issue.
2016-04-05
Journal Article
2016-01-0310
Xinran Tao, John R. Wagner
Abstract The pursuit of greater fuel economy in internal combustion engines requires the optimization of all subsystems including thermal management. The reduction of cooling power required by the electromechanical coolant pump, radiator fan(s), and thermal valve demands real time control strategies. To maintain the engine temperature within prescribed limits for different operating conditions, the continual estimation of the heat removal needs and the synergistic operation of the cooling system components must be accomplished. The reductions in thermal management power consumption can be achieved by avoiding unnecessary overcooling efforts which are often accommodated by extreme thermostat valve positions. In this paper, an optimal nonlinear controller for a military M-ATV engine cooling system will be presented. The prescribed engine coolant temperature will be tracked while minimizing the pump, fan(s), and valve power usage.
2016-04-05
Technical Paper
2016-01-0312
Robert S. Jane, Gordon G. Parker, Wayne Weaver, Denise M. Rizzo
Abstract Vehicles with power exporting capability are microgrids since they possess electrical power generation, onboard loads, energy storage, and the ability to interconnect. The unique load and silent watch requirements of some military vehicles make them particularly well-suited to augment stationary power grids to increase power resiliency and capability. Connecting multiple vehicles in a peer-to-peer arrangement or to a stationary grid requires scalable power management strategies to accommodate the possibly large numbers of assets. This paper describes a military ground vehicle power management scheme for vehicle-to-grid applications. The particular focus is overall fuel consumption reduction of the mixed asset inventory of military vehicles with diesel generators typically used in small unit outposts.
2016-04-05
Technical Paper
2016-01-0308
Tomasz A. Haupt, Angela E. Card, Matthew Doude, Michael S. Mazzola, Scott Shurin, Alan Hufnagel
Abstract The Powertrain Analysis and Computational Environment (PACE) is a forward-looking powertrain simulation tool that is ready for a High-Performance Computing (HPC) environment. The code, written in C++, is one actor in a comprehensive ground vehicle co-simulation architecture being developed by the CREATE-GV program. PACE provides an advanced behavioral modeling capability for the powertrain subsystem of a conventional or hybrid-electric vehicle that exploits the idea of reusable vehicle modeling that underpins the Autonomie modeling environment developed by the Argonne National Laboratory. PACE permits the user to define a powertrain in Autonomie, which requires a single desktop license for MATLAB/Simulink, and port it to a cluster computer where PACE runs with an open-source BSD-3 license so that it can be distributed to as many nodes as needed.
2015-09-29
Technical Paper
2015-01-2733
Samraj Benedicts, Vivek Seshan
Track tensioning assembly is used in tracked vehicles to maintain the tautness of the track. The track tensioning system consists of the rear idler wheel which applies pressure on the track and a mechanism to increase or decrease the tension. This paper is a study of reaction forces and its effects on the chassis due to rear idler position. Rubber track layouts have been focus for most of the research work, here we study the effect of rear idler position on chassis structure through simulated analysis. An agriculture paddy combine harvester with rubber track is considered for the purpose of this work. Firstly the complete chassis structure is modeled in 3D using Creo and exported to Pro Mechanica for simulation. The real time forces, constraints were applied and the results were correlated to actual field results. The simulations were optimized through several iterations to match the field test results.
2015-09-29
Technical Paper
2015-01-2861
Burcu Guleryuz, Martin Raper, Cagkan Kocabas
Abstract Dimensional Variation Analysis (DVA) is a decision-making methodology for tolerance analysis, and is employed to evaluate assembly variations and identify problems in manufacturing assembly processes at early stages of design. In this study, the impact of component tolerances on manufacturing and assembly process variations is presented on a case study. The case study includes the alignment analysis between crankshaft and input shaft for clutch systems. The impact of component tolerances on axial alignment measurements in regard to these applications is discussed. The study shows that when combined with effective tolerance combinations, Variation Simulation Analysis (VSA) facilitates operational visibility; thus improve quality, reduce manufacturing cost, and enable reduction of production release time. The case study presents the impact of component tolerances at two levels: 1. Pre-Design, 2. Optimized Design.
2016-01-05
Journal Article
2015-01-9086
Geethanjali Gadamchetty, Abhijeet Pandey, Majnoo Gawture
The three parameter Ramberg-Osgood (RO) method finds popular usage for extracting complete stress-strain curve from limited data which is usually available. The currently popular practice of assuming the plasticity to set in only at the Yield point provides computational advantage by separating the complete nonlinear curve, obtained from RO method, into elastic and plastic regions. It is shown, with an example problem, that serious errors are committed by using this method if one compares the obtained results with results of complete stress-strain curve. In the present work we propose a simple Taylor series based approach based on RO method to overcome the above deficiency. This method is found to be computationally efficient. The proposed method is applicable for stress-strain curves of materials for which RO method provides a good approximation.
2016-02-01
Technical Paper
2016-28-0231
Kiran Balkrishna Modak, Abir Majumdar, Amit Thakur, Chintamani A Mhaskar, Vikas Bhardwaj, Rajesh Bhangale, Mahadev Pawar, Rajiv Aggarwal
Abstract In this era of engine downsizing, the powertrains with higher power densities are configured on next generation vehicles. The bare four cylinder engine without balancer shaft has higher surface velocities, sound pressure & power levels and nearly 10 to 15% higher base level vibration/forces over older generations. Adapting such engines on a new vehicle platform with stringent NVH targets is challenging. Powertrain mount modal analysis, 6DOF or 16DOF is a primary tool followed for initial mount positioning and stiffness definition. From our earlier experiences we have the knowledge that most of the 6DOF iterations lead to the mount positions which are less feasible as per vehicle architecture and packaging point of view, and further optimization is needed to arrive at suitable mount position through 6DOF analysis.
2016-02-01
Technical Paper
2016-28-0242
Ashwin Vaidyanathan, Aono Noriaki
Abstract This paper reinforces the importance of correlation between CAE Analysis of CAB Bridge and Vehicle test data. CAB Bridge is a structural assembly, bolted to the Frame of a Truck. The initial objective of the study was to evaluate the influence of particular design modification on CAB Bridge. To perform CAE calculations, two different iterations of Boundary & loading conditions, were established and executed using CATIA V5. During Post processing of CAE results, detailed data analysis and interpretation were performed. The results of CAE Analysis and Vehicle test data were compared, to identify the iteration that correlated better with Vehicle test data. The data analysis and interpretation guided in finding key observations and concluding that the Torsion case as the most important loading condition.
2017-03-28
Technical Paper
2017-01-0261
Randolph Jones, Robert Marinier III, Frank Koss, Robert Bechtel, John A. Sauter
Abstract When evaluating new vehicle designs, modeling and simulation offer techniques to predict parameters such as maximum speed, fuel efficiency, turning radius, and the like. However, the measure of greatest interest is the likelihood of mission success. One approach to assessing the likelihood of mission success in simulation is to build behavior models, operating at the human decision-making level, that can execute realistic missions in simulation. This approach makes it possible to not only measure changes in mission success rates, but also to analyze the causes of mission failures. Layering behavior modeling and simulation on underlying models of equipment and components enables measurement of more conventional parameters such as time, fuel efficiency under realistic conditions, distance traveled, equipment used, and survivability.
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