An efficient lightweight construction for crash-relevant structural parts through intrinsic hybridizationWednesday (29.04.2020) 10:20 - 10:40 Room 1
Hybrid structures offer a combination of weight reduction with improved mechanical properties in contrast to monolithic constructions. Parts made of fiber reinforced polymer (FRP) and ductile metal can for example bear high operational loads on the one hand. On the other hand, the resulting parts enables high energy dissipation capabilities within crashes. A key requirement for the utilization of these hybrid parts within large-scale production routes is the availability of efficient manufacturing processes. This contribution presents a novel intrinsic manufacturing approach for hybrid composite parts, optimized for crash applications. The production of the geometry as well as the hybridization are realized in one combined manufacturing step.
The mechanical properties of the hybrid part strongly depend on the interface be-tween its single components. A combination of mechanical form fit and adhesive bonding significantly improves the interface performance. An additional coating, which is based on an organically modified silicate, on the metallic insert functions as an adhesive promoter and a corrosion barrier between the thermoplastic matrix of the FRP and the metal. The form fit is directly created during the part manufacturing process. Hereto, an innovative metallic insert is designed. Due to its geometry, out-of-plane deformations are induced by a tension force and result in the generation of form fit elements. During the global forming process, these form fit elements penetrate the molten polymer and the form fit arises.
Aiming for an efficient dimensioning process, the mechanical behavior of the parts is modeled and simulated having regard to the manufacturing history. To capture the properties of the applied components, nonlinear material models at large strains are developed based on directly connected rheological elements. Moreover, the complex inner and outer geometry, which are influenced by the manufacturing process, are taken into account by simulating sub steps of the fabrication process. Consequently, requirements on the process control can be deducted from finite element simulations with varied process parameters.
Additionally, the rate-dependent deformation behavior of the hybrid composite is experimentally investigated. To this end, a specimen geometry is developed to especially characterize the interface between the FRP and the metal at high strain rates in a Split-Hopkinson Pressure Bar.