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| 2. |
- Berghuvud, Ansel, et al.
(författare)
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Consequences of nonlinear characteristics of a secondary suspension in a three-piece freight car bogie
- 2001
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Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 36:1, s. 37-55
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Tidskriftsartikel (refereegranskat)abstract
- Mechanical systems with nonlinear characteristics can show a complex dynamic behavior that should be taken into account when analysing dynamic performance and reliability. The dynamic behavior of the main suspension in a three-piece freight car bogie with constant friction damping is considered in this work. The aim is to investigate the vertical behavior of a specific suspension design due to different driving conditions, weather and wear of the friction wedges. A variation in weather and wear is represented by different friction configurations in the model of the suspension. Models of different levels of detail that are based on experimental data on existing designs are developed. It is found that the suspension performance is very sensitive to variations of the friction configuration and this indicates a possible presence of nonlinear dynamic phenomena at in service like conditions
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| 3. |
- Carlbom, P., et al.
(författare)
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Passengers, seats and carbody in rail vehicle dynamics
- 2002
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Ingår i: Vehicle System Dynamics. - 0042-3114 .- 1744-5159. ; 37, s. 290-300
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Tidskriftsartikel (refereegranskat)abstract
- Reliable models of passengers, seats and carbody are essential in order predict ride comfort of rail vehicles. This paper extends previously presented models of passenger-carbody interaction to include vertical seating dynamics. The proposed basic model is based on experimental modal analysis of a rail vehicle with and without passengers. The nations of human-body normalized apparent mass and seat transmissibility are fundamental an the modelling. The possibility of using reduced and approximate gels is also discussed in the paper. The proposed models are easy to use and implemented in commercial rail vehicle software.
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| 4. |
- Chaar, Nizar, et al.
(författare)
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Experimental and numerical modal analyses of a loco wheelset
- 2004
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Ingår i: Vehicle System Dynamics. - 0042-3114 .- 1744-5159. ; 41:Suppl., s. 597-606
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Tidskriftsartikel (refereegranskat)abstract
- Wheelset structural flexibility is believed to have a major influence on the vehicle-track dynamics. Several studies have related the structural flexibility of the wheelset to fluctuations of wheel-rail forces, rail and wheel corrugation, etc. This paper reports part of an ongoing project that studies the effects of wheelset structural flexibility on the vehicle-track dynamics. The paper focuses on experimental and numerical modal analyses of a loco wheelset in the frequency range of 0-500 Hz. Major issues related to modal analyses and modelling of wheelset are presented along with respective results. The results from numerical modal analysis were in good agreement with those obtained from the experiment. In addition, the wheelset had fairly low eigenfrequencies. Reduced versions of the generated wheelset model will be used in coming work in on-track numerical simulations in order to determine the effects of wheelset structural flexibility on the vehicle-track dynamics. Results from these simulations will be validated against existing experimental on-track results.
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| 5. |
- Drugge, Lars, et al.
(författare)
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Modelling and simulation of catenary-pantograph interaction
- 2000
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Ingår i: Vehicle System Dynamics. - : Taylor & Francis Ltd.. - 0042-3114 .- 1744-5159. ; 33:suppl, s. 490-501
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Tidskriftsartikel (refereegranskat)abstract
- Modelling and simulation of the dynamic behaviour of catenary-pantograph interaction is an important part when assessing the capability of a current collection system for railway traffic. The large variation in infrastructure characteristics in different countries and railway companies, different types of traffic, designs of pantographs etc. makes it almost impossible to develop a final simulation model of such a system. Instead, it would be favourable to have a tool that has the ability to set up models of such systems, choose relevant detail of the models, run simulations and finally visualize the results. To make the tool useful for engineers, design experts as well as simulation experts, the functionality of the tool must be worked out. Aspects on computer simulation such as developed models, simulation methods and computer tools are presented. The aim is to develop a scenario that considers different designs, models, solution methods and user levels. The scenario focuses on how to structure the use of simulation of dynamics in catenary-pantograph development. A scenario is sketched built on different user levels, a modular structure and a structure for information management
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| 6. |
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| 7. |
- Gäfvert, Magnus, et al.
(författare)
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A 9-DOF Tractor-Semitrailer Dynamic Handling Model for Advanced Chassis Control Studies
- 2004
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Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 1744-5159 .- 0042-3114. ; 41:1, s. 51-82
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes a flexible and modular 9-degrees-of-freedomnonlinear dynamic handling model for a tractor-semitrailer combinationvehicle. The equations of motion are derived from the fundamentalequations of dynamics in Euler's formulation. The primary aim of themodel is simulations of handling scenarios with active yaw control,using unilateral braking and possibly tractor rear wheel steering. Theapplications of the model are not limited to this domain, but mayprove useful in other areas of tractor-semitrailer handling analysisor hardware-in-the-loop simulations. The model is formulated as astate-space model that may be implemented in standard simulationenvironments. A Simulink implementation is presented. Simulationresults are compared with experiments to validate the model.
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| 8. |
- Harell, Pia, et al.
(författare)
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Multiple pantograph operation : effects of section overlaps
- 2004
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Ingår i: Vehicle System Dynamics. - : Taylor & Francis. - 0042-3114 .- 1744-5159. ; 41, s. 687-696
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Tidskriftsartikel (refereegranskat)abstract
- The traffic situation of the future goes towards flexibility of train configurations and increasing speed. There is a need for the ability to adjust the number of passenger cars as well as the energy consumption for trains to run efficiently, leading to multiple pantographs and short pantograph distances. Limitations due to this were studied on an existing catenary system. A model of the pantograph catenary system was developed in a finite element program. To verify the correctness of the model, comparison with full scale experiments was done. Results from the simulations indicates that trailing pantographs suffers from high dynamic effects within the section overlap. Effects of changes in design of the section overlap was studied. The results show that it is possible to get lower dynamic effects in the section overlap, even lower than within an ordinary span.
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| 9. |
- Holen, Peter, et al.
(författare)
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Possibilities and limitations with distributed damping in heavy vehicles
- 2004
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Ingår i: Vehicle System Dynamics. - 0042-3114 .- 1744-5159. ; 41, s. 172-181
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates passive damping performance in heavy vehicles. The objective is comparison of conventional individual dampers and system with modally distributed damping. An analytical model with 7 DOF is first used to derive theoretical damping expressions. Considered degrees of freedom are for sprung mass; bounce, pitch, roll and for unsprung mass; bounce and roll. Vehicle simulations are then performed with a 4x2-tractor semitrailer combination. Load cases of both ride and handling character are used for damping system evaluation and comparison. The vehicle model with conventional individual dampers is validated against measurement data.
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| 10. |
- Jarlmark, Jonas
(författare)
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Modelling and validation of steering system response to road and driver induced forces
- 2004
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Ingår i: Vehicle System Dynamics. - 0042-3114 .- 1744-5159. ; 41:SUPPL., s. 371-380
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Tidskriftsartikel (refereegranskat)abstract
- The driver serves both as a controller for the vehicle direction as well as a sensor for the road induced forces. A vehicle model is developed with both computer simulations as well as driving simulator use in mind. Therefore, the included steering system model was divided into one part below and one part above the steering gear. The presented steering system model focuses on force transmission from the wheels to the steering rack and the rack movements including a friction model. Above the steering gear, the model focuses on servo control through the twist of a torsion bar and includes steering wheel inertia and steering column stiffness and friction. The vehicle model has ten degrees of freedom, includes a Magic Formula 5.1 tyre model and is validated together with the steering system model as well as a geometric road model as a complete vehicle-environment model. The validation is made using data from the KTH experimental vehicle in a number of isolated driving cases performed at the Volvo Hällered test track. The simulations performed with the model are mainly focused on the steering wheel moment, sensed by the driver.
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