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Various methods have been used for introducing fire retardant additives into polymers. Deposition of thick fire retardant coatings directly onto polymer substrates is an alternative technique. An important Advantage of the coating technique is the preservation of the physical and chemical integrity of the polymer material. Moreover, the fire retardancy of the polymer materials can be achieved following their production. Suitable coating materials are inorganics, intumescent, char-forming, oxygendiluting, and cooling or radical quenching layers. The most important problem is to achieve sufficient coating thickness to withstand the direct attack of flame and to protect the polymer bulk from pyrolysis, otherwise blistering of coating, caused by emitted pyrolysis gases, is often observed.
To avoid blistering of coating, the adhesion between polyolefin Substrate and fire retardant coating has to be extraordinarily high.
In order to achieve such a high level of adhesion, the polymer surface has to be modified with adhesion-promoting functional groups. The deposition of thin plasma polymers as adhesion-promoting layers with NH2, OH or COOH groups has been the most suited method. These functional groups are able to form covalent bonds and other interactions between the fire-resistant coating and the plasma-modified polyolefin substrate.
Additionally, the plasma polymer counteracts the strong mechanical stresses in the laminate on exposure to high temperatures by its flexibility. The thick fire retardant coatings were chosen based on “green” ecological aspects to avoid flame-initiated emission of toxic or corrosive gases and remains of toxic char.
In impact simulations, the instantaneous change of velocity in the contact area can lead to artificial oscillations. These oscillations might significantly influence the results, especially when nonlinear and rate dependent constitutive formulations are used.
In this work, a nonlinear penalty formulation similar to a soft contact formulation is presented.
Within the TF-project SiVi the BAM occupies itself interdisciplinary with the safety of traffic infrastructures considering extremely severe damage events. Therefore, a scenario of fire inside a traffic tunnel induced by a gas cloud explosion is chosen as representative. Additionally, a dangerous goods transporter shall be involved in the scenario.
As further aspect which shall be investigated is the use of liquefied natural gas (LNG) as fuel support in transport vehicle like trucks in future. The main component of LNG is methane as a flammable gas. To transport a sufficient amount of fuel the methane is cooled down at -161°C, its boiling point. In liquid phase LNG is compressed 600 times more than in gas phase.
The issue of department 2.4 is to identify the hazards for people and the tunnel structure located in the surrounding whilst a potential release of LNG out of a leaking tank occurs. Therefore, the temporal and spatial distribution of the gas cloud within the tunnel structure shall be recorded.
Basis for this will be experiments in 1:1 at BAM test rig TTS as well as numerical analysis within ANSYS CFX. On top ignition tests of the distributed gas cloud in a down scaled model allow statements on the emerging maximum pressure and temperature.
Das Poster stellt ein Konzept zur Bewertung der strukturellen Integrität von havarierten Tankbehältern vor. Es wurde ein dehnungsbasiertes Konzept eingeführt, welches einen Brückenschlag zwischen duktiler Schädigung und dem Integritätszustand des Behälters herstellt. Diese Thematik entspringt aus einem Kooperationsvorhaben der Organisationseinheiten 5.2 und 3.2.