In the project OPAL, supported by the German Federal Ministry of Educa
tion and Research, we seek to understand and improve the production process as well as material properties of non–woven materials which play, for example, an important role as light weight damping material in cars. For this project departments of the Fraunhofer ITWM Kaiserslautern, TU Kaiserslautern and FAU Erlangen, along with the industrial partners Autefa Solutions Germany GmbH and IDEAL Automotive GmbH, worked together to describe the fibre flow in a turbulent air stream, the lay down and material building as well as virtual tensile tests on the simulated material.
Our particular role in this project within the department of Industrial Mathematics at TU Kaiserslautern is to simulate non–woven materials in the lay-down area. A very interesting aspect in this research is to include the non–intersection property of the fibres. Existing surrogate models do cover the main basic features of the lay–down behaviour of fibres on the transport belt. However, those models do not account for the fibre thickness and therefore allow for unrealistic intersections. To realise that the fibres do not intersect, we extend the existing lay–down models by introducing an interaction potential, which accounts for the non–intersection property of real fibres along the whole fibre paths. This naturally leads to a strongly coupled system of Stochastic Functional Differential Equations with delay. To analyse the influence of this new interaction part with delay, we consider the model on different levels of the model hierarchy.
The other important aspect within this project is the simulation and virtual construction of three dimensional non–woven materials incorporating original fibre properties, machine and CT data and to couple our simulation to the fibre distributions in the lay–down area which we seek from detailed computer simulations for a representative group of staple fibres in a turbulent air stream performed by Fraunhofer ITWM. Finally, on the basis of such virtual materials, virtual tensile tests can be performed at FAU Erlangen.
For more information contact Christian Neßler (nessler@mathematik.uni-kl.de).