Simulation of an airbag deployment in out-of-position situations

The commonly used 'uniform pressure method' (UP) is a well-tried method to simulate an airbag deployment in accident cases. Nevertheless, this method indicates rather heavy inadequacies at the examination of the airbag deployment in the first milliseconds. A solution is the airbag deployment calculation by using computational fluid dynamics (CFD) methods, wherein the calculated gas flow pressure may be applied 'correctly' to the airbag shell elements.

This CFD simulation is integrated in LS-Dyna with the so-called Arbitrary Lagrangian Eulerian (ALE) method and in this review the result's accuracy will be discussed. According to the FMVSS 208, an OoP model will be built-on and comparisons with simulations and tests are done. Another important detail in this labour is the airbag cover examination and the tear seam modelling, as a trivial FE modelling cannot be done due to the very fine mesh. So two possible solutions for tear seam modelling are introduced and discussed. Furthermore considerations concerning the gas generator combustion will also be revealed and an analysis about the impossibility of the direct comparison between gas generator tank test and airbag deployment will be done. At least some parameters, which take effects in the simulation, are researched and evaluated, so finally an optimised simulation model can be made available for further examinations.     

High performance installation for drill and blast advance Mitholz, Switzerland

The section Mitholz of the L tschberg Alp - Transit tunnel consists basically of 3 drill & blast advances with a cross section of 63 - 69m2 and a total length of 25 km.The high - performance back - up installation in use distinguishes itself by the following substantial innovations:The joint venture SATCO ( STRABAG AG, Rothpletz, Lienhard & Cie. , Walo Bertschinger AG, Vinci Construction,Skanska Europe AB), the c ontractor in charge, is achieving very high rates of advance, thanks to the high - performance back - up installations.- The chosen heading system has a positive effect on the entire construction program. Supplementary work can be done within the planned time schedule - Owing to the excellent performance, the joint venture SATCO is ahead on the construction program by about 700m.- The high rates of advance result for the customer in a positive return on investment - The installed equipment results in a higher safety at the workplace for the workers