Institute of Dynamics and Vibration Research (IDS) of Leibniz Universität Hannover is part of the faculty of mechanical engineering with a staff of 30 PhD students. One of their fields of interest is the surface modification of technical components to tailor friction, wear and contact properties. They collaborative on different applications in European and national funded projects as well as bilaterally with industrial companies.
About the role in the CO-VERSATILE project:
Most of the protective equipment is on the one hand in direct contact to the body and on the other hand it has to fulfil a technical function, e.g. gloves – grabbing and holding, mask – sticking in place with as much comfort as possible, parts of respirators or filters need a defined friction in contact to its counterparts. In order to optimize these functions, the surface properties of medical products play an important role, i.e. roughness, texture, adhesion. Also wear resistance plays an important role for certain products. Partner LUHs main task is to define the surface properties for a component or a product to optimize its function based on materials used and operating conditions such as contact pressure, desired friction behaviour and fluids in contact. The surface properties are then translated into Laser Surface Texturing (LST) parameters together with mould laser expert SME ML Engraving. At LUH we use simulation tools covering the component’s geometry and material (FEA) as well as contact and friction models to predict its interaction with contact partners. In terms of friction of rough and textured surfaces, we are able to describe adhesion, mixed friction and (elasto-)hydrodynamic regimes, in terms of wear we transfer laws derived from rubber tire and plastic seal industry onto medical products. Another task of LUH will be (virtual) testing of products in terms of friction and wear as well as durability under typical operating conditions. For this issue we create a technical digital twin of the product with the help of our FEA and friction/wear tool mentioned above. As an innovation we will only need data information from our project partners (drawing, material selection, surface definition of product/mould, operating conditions from customer), which is a big lead time advantage compared to sending samples between partners. In case of radical new product development, when the build-up of a digital twin will not work due to lack of data, we will make use of in-house rapid prototyping with a combination of additive manufacturing (LSR or all kinds of plastic parts). Surface finishing is applied as a post-process (shot peening, multi-stage grinding, lapping, laser texturing), so that we can directly replicate the surface finish of moulded parts of our project partners. These prototypes can be tested in our test rigs in terms of friction, wear, compatibility, durability under all relevant operating conditions.