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Eingeladener Vortrag
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The interaction of the vehicles with the pavements imply damaging effects on both systems, as a function of the operating conditions and design characteristics of both systems. These effects influence the road pricing as well as the maintenance costs of the vehicles. In this paper, a simulation scheme has been proposed to analyze such interaction in massive way, involving a multivehicle models was the uncoupling of the roll and pitch responses. Results suggest that the damaging effects on the pavement and the vehicle, depends on the position along the road profile. However, the vertical design of the road would mainly affect the pavement damage, while the turning maneuvers would strongly influence the damage of the vehicle. Many uses can be identified for the proposed simulation scheme, involving different design and operating conditions for both systems.
Rear-end crashes involving heavy trucks as the leading vehicle, and cars as the impact vehicle, cause many deaths and permanent injuries to car´s occupants. Measures have been thus taken in the trucks to prevent underride crashes, including the mounting of stiffer underride guards, set at car´s bumper height. In this respect, an active acceleration system(AAS), installed in the truck, could also contribute to mitigate the effects of These crashes, through the decrease of the relative Speed of the vehicles at the instant of the crash. In this paper, an AAS system is proposed, under the principles of ultrasonic sensors and an actuator for the truck´s accelerator mechanism. Simulation results of the operation of this AAS system, suggest that such a system could decrease the relative impact speed around 8% for an initial relative speed of 10 m/s.
A dynamic simulation model for a tanker ship along the Rhine River has been proposed, based on a simplified computational scheme, involving a two-degree-of-freedom roll plane multibody system, subjected to lateral accelerations estimated on the basis of measured data. The resulting equations of motion are solved through the transition matrix approach. The results suggest that many contributing factors were involved in the capsizing of the ship, including the relatively high speed of the river water and the meandering path of the infrastructure, further affected by dynamic effects derived from the behavior of the payload and from the steering maneuvers performed.
A novel deign of test equipment has been commissioned to investigate thermal stratification and boiling during fire exposure of pressure vessels. Extensive temperature measurements and video of the internal conditions during fire exposure are possible, and the equipment has been designed for future compatibility with laser-based velocity measurement techniques. It is expected to generate data large quantities of data that will be of use in validation of two- and three-dimensional CFD models for the prediction of pressure vessel behaviour in fire. Future work will seek to characterize the boundary layer conditions in detail for a range of test fluids, fill levels and fire-induced thermal boundary conditions.
Initial tests undertaken during commissioning may indicate that fire exposure of the vessel wall just above the liquid level can have a notable influence on the pressurization rate, by increasing the degree of superheat. Further experimental and modelling work is required to confirm and quantify this effect, or to rebut this conclusion.
The application of lightweight materials for tanks for transportation appears promising. Besides saving weight and therefore transportation costs, new complex geometries that depart from common cylindrical shapes of steel tanks can be manufactured. For transportation of dangerous goods, fire and explosion safety must be maintained to prevent accidents with serious consequences. In this work the fire behavior of lightweight tanks made from glass fiber reinforced plastics (GFRP) with complex geometries is investigated. Pretests on intermediate scale GFRP plates are conducted to identify suitable fire protection systems and surface treatments for composite tanks. The fire resistance is shown to be improved by addition of fire protective coatings and integrated layers. Finally, a complex rectangular GFRP tank with a holding capacity of 1100 liters is fire protected with an intumescent fire coating. The tank is filled up to 80 % with water and burned under an engulfing fully developed fire. It was shown that the intumescent layer could expand before the decomposition of the resin occurred. Furthermore, the adhesion between tank surface and coating was maintained. The structure could withstand a fire for more than 20 min.
The vessel wall response shows a good agreement between the numerical predictions of and experimental data using the limit load approach. Further work is continuing to understand the thermohydraulic response and the boundary conditions for material modelling. As shown in figure 2 there was one BLEVE of a bare tank containing a PRV, highlighting the risk of serious consequences if models are inaccurate. The behavior of partly coated tanks were similar to the bare tank.
A simplified model, based upon physical principles, is proposed the simulate the effect of sloshing on the pressure developed in the tanker chambers. The model has been validated in good extent, with experimental data from full scale testing. The characteristic that mostly affects the pressure developed with the chambers of the tanker is the length of the chamber. While a reduction in this property could decrease the pressure developed within a given chamber, the analysis should take into account an overall approach, as a shortening of the individual chambers would influence the number of chambers necessary to carry a certain amount of product. Consequently, the resulting model could be used to study different effects of the sloshing cargo on the carrying vehicles, including the length and position of the chambers along the tanker body.