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- Zeitschriftenartikel (21) (entfernen)
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- Fire (3)
- Experimental methods (2)
- Experimental modelling (2)
- GFRP (2)
- LNG (2)
- Lightweight design (2)
- Liquid cargo (2)
- Load transfer (2)
- Road tankers (2)
- Simulation (2)
- Sloshing (2)
- ABS (1)
- BLEVE (1)
- Bogie´s yaw friction (1)
- Bogie´s yaw stiffness (1)
- Braking in a turn manoeuvre (1)
- Braking-in-a-turn maneuver (1)
- Carburizing (1)
- Cargo shifting (1)
- Cargo sloshing (1)
- Centre plate (1)
- Continuous wavelet transform (1)
- Cryogenic Vessels (1)
- Decarbonization (1)
- Drag resistance (1)
- Driving style (1)
- Dry friction (1)
- Dynamic loads (1)
- Empirical mode decomposition (1)
- Energy efficiency (1)
- Energy losses in transportation (1)
- Environmental assessment (1)
- Filling procedere (1)
- Finite element method (1)
- Fire safety composite tanks (1)
- Frequency analysis (1)
- Friction energy (1)
- Fuel consumption (1)
- Furnace design (1)
- GPS data (1)
- Gravity response (1)
- Health monitoring (1)
- Hunting phenomenon (1)
- JetFire (1)
- Jetfire (1)
- LH2 (1)
- LPG (1)
- Lateral load transfer (1)
- Liquefied Hydrogen (1)
- Liquefied Natural Gas (1)
- MLI (1)
- Mechanical fatigue (1)
- Mechanical modelling (1)
- Mechanical prtoperties (1)
- Multilayer Insulation (1)
- Particle emissions (1)
- Pendulum analogy (1)
- Pendulum-analogy (1)
- Pressure vessel (1)
- Prüfstand (1)
- Prüftstand (1)
- Rail damage (1)
- Rail tankers (1)
- Rail vibrations (1)
- Railroad (1)
- Railway braking forces (1)
- Railway vibration measurements (1)
- Receptacle (1)
- Roll reactions (1)
- Rolling resistance (1)
- Safety (1)
- Selective carburizing (1)
- Self-centering mechanism (1)
- Stored energy (1)
- Substructure failures (1)
- Tank (1)
- Test (1)
- Thermal properties (1)
- Tiefkalt (1)
- Transfer function (1)
- Transport efficiency (1)
- Transport safety (1)
- Transportation energy (1)
- Turning (1)
- Turning forces (1)
- Turning maneuvers (1)
- Vibration signal analysis (1)
- Wheel forces (1)
- Wheel-rail friction coefficient (1)
- Wheel-rail tangential forces (1)
Organisationseinheit der BAM
- 3.2 Gefahrguttanks und Unfallmechanik (21) (entfernen)
Hunting is a potentially dangerous phenomenon related to the lateral oscillation of the wheels that impacts the rails and causes the wear of the infrastructure’s components. Therefore, the analysis and timely detection of hunting can lead to the application of corrective maintenance tasks, reducing damages, and costs and even derailments as a result. In this work, the vibration response of a finite element model of a rail with hunting-induced loads by a single wheel is analyzed in three directions: longitudinal, lateral, and vertical. The contact patch forces are calculated by means of Simpack® using the Kalker linear theory and the contact Hertz theory. The system is solved by using the Newmark-_ approach. The results of the deflection and vibration analysis, following the proposed methodology, show how the different characteristics of the loads impact the rail.
The objective of this paper is to describe and to validate a simplified pendulum-analogy model to simulate the interaction of a liquid cargo with ist carrying vehicle. The resulting testing rig consists of a rectangular container, spring supported on a two wheelset-bogie having a scale down of 1/10 with respect to a full-size equipment. The testing rig is used to validate a simple pendulum-based, simplified three degree-of-freedom mathematical model of the response of a partially filled container to lateral accelerations. The length of the pendulum is set according to validated methodologies. The resulting mathematical scheme reveals a high correlation with the experimental output, on the order of 99%, while some other performance measures, related to the peak forces and the range of variation of the wheel-rail forces, also show good concordance with the experimental results.
A methodology is proposed for the experimental analysis of the liquid cargo effect under combined orthogonal accelerations. To simultaneously subject the vehicle-cargo system to longitudinal and lateral accelerations, the vehicle is set obliquely on a tilt table. The experimental outputs suggest that there is a significant effect of the liquid cargo on the lateral load transfer ratio (LTR), on the order of 20%, which is attributable to the resulting shifting of the liquid cargo’s centre of gravity. That is, the peak LTR values due exclusively to sloshing were not significant, in such a way that the liquid cargo would only pose a safety risk under a steady acceleration input.
Also, the inverse of the product of the magnitude of the acceleration times the free surface length, correlates with the liquid cargo effect. That is, the magnitude of the input acceleration is not fully determinant for greater load transfers.
This paper presents a method for processing acceleration data registered on a train and determining the health condition of a subway’s substructure. The acceleration data was converted into a dynamic deformation by applying a transfer function defined using the Empirical Mode Decomposition Method.
The transfer function was constructed using data produced on an experimental rig, and it was scaled to an existing subway system. The equivalent deformation improved the analysis of the dynamic loads that affect the substructure of the subway tracks because it is considered the primary load that acts on the track and substructure. The acceleration data and the estimated deformations were analyzed with the Continues Wavelet Transform. The equivalent deformation data facilitated the application of a health monitoring system and simplified the development of predictive maintenance programs for the subway or railroad operators. This method better identified cracks in the substructure than using the acceleration data.
Die BAM – Bundesanstalt für Materialforschung und -prüfung führt schon seit vielen Jahren auf zwei Brand- prüfständen Brandprüfungen z.B. an Transport- und Lagerbehältern für radioaktive Stoffe oder zur Prüfung von Brandschutzbeschichtungen durch. Als Brandmedium wird auf diesen Prüfständen Flüssiggas (Propan- Butan-Gemisch C) eingesetzt, mit dem die Prüfobjekte simulierten Unfallfeuern ausgesetzt werden. Mit dem neuen Jetfire – Prüfstand der BAM können seit Anfang 2018 diverse Belastungsszenarien nach den Anforde- rungen der ISO22899-1:2007 [1] simuliert werden.
Wheel forces generate stresses in the rail as a function of several vehicle and infrastructure characteristics and operating conditions. The different components of the wheel forces develop strains in the rail which contain an elastic and hysteretic (irreversible) components. The irreversible deformations of the rail would be associated with locomotive energy losses. In this paper, a testing facility is proposed to indirectly characterize the level of stresses in the rail, in terms of the energy that is lost during tuming maneuvers. Different potentially influential factors are considered, including the friction at the Center plate, the wheelbase length, the distance between bogies and the radius of the curved track. The change
in the potential energy during a U-turn displacement is measured. In this respect, an experimental model under this operating principle, aimed at validating such a principle of Operation, reveals a significant effect of the friction at the center plate on the energy lost during turning maneuvers, and consequently, on the level of stresses in the rail.
An overview of test standards and regulations relevant to the fire testing of pressure vessels
(2021)
Fire exposure of storage and transportation vessels of hazardous materials (including pressure liquefied gases) can result in BLEVEs and other high-consequence incidents with large societal and economic impacts. To reduce risk most countries have numerous regulations, codes of practice and guidance notes covering the design, operation and maintenance of vessels and thermal protection systems. Yet despite such regulations there remains no internationally accepted fire test procedure for pressure vessel and accompanying thermal protection systems that is capable of meeting a range of regulatory requirements. This paper considers some of the regulations in place in the western world and considers the origin of these based on large and medium-scale testing conducted to date. It examines conditions found in these tests to propose a set of recommendations on which to base a standard method of test. These recommendations are proposed as being representative of a credible large pool fire scenario that may occur.
In spite that transport activities do not represent the biggest contributor of pollutants emissions, their reduction has been a priority as some other externalities are associated to such emissions and to the transport itself. A crucial element to characterize the behavior of the vehicles against the environment are the losses that such vehicles exhibit in a passive way, that is, without any involvement of power conditions. The energy loses due to the rolling, the drag and to the friction in mechanical components, have been assessed so far in terms of the stopping acceleration when the vehicle idles on a ramp. However, such a testing procedure produces some uncertainties due to the dynamic conditions that are considered. To avoid such critical limitations, in this paper a testing procedure and facility are proposed, which are based on static conditions of the vehicle at the initiation and at the ending of the test, which are assumed to provide a better reliability to the testing. Some preliminary theoretical analysis should be made in order to validate the operational principles proposed herein for such testing facility.
Different approaches have been attempted so far to reduce fuel consumption and linked pollutants, including vehicle equipment and design, with rational driving style being recognized as a potential source of fuel savings. However, no specific methodology had been suggested so far to assess fuel economy of driving other than the fuel consumed itself. In this paper, the Standard deviation of driving acceleration has been found to be directly associated to fuel consumption, so that the less dispersion of the driving acceleration, produces the lower fuel consumptions and emissions. Such metric could be thus used to assess driving style.
Turning maneuvers originate higher forces exerted on the rail and the loss of locomotive energy, at a rate that is function of several parameters that influence the magnitude of the developed horizontal wheel-rail forces, including the friction at the centre plate and the bogie´s yaw stiffness. However, such a friction at the contact surfaces of the centre plate is needed to mitigate the Hunting phenomenon when the train moves on straight track segments. In this paper, a self-centering centre plate is proposed, consisting of a lubricated centre plate, equipped with a spring- and damper-based self-centering mechanism. Simulation results of the proposed mechanism suggest that the energy performance in turns of a train car equipped with such self-centering centre plate is comparatively better, as the peak friction forces linked to the dry friction at the contact surfaces of current centre plate designs, are avoided. The assessment of the hunting performance of the proposed device in straight track segments is proposed as the continuation of this work.