Variable Curved Profiles made of Fiber-Plastic Composite


Compared to conventional structural profiles made of steel or aluminum, profiles made of fiber-plastic composites exhibit both, high lightweight potential and excellent resistance to corrosion. However, widespread use is hindered by the fact, that the prevailing thermoset processing methods only allow the production of straight profiles or those with predefined radii of curvature, with a separate mold being required for each new profile shape.

Together with the Chair of Forming Technology at Siegen University and the industrial partners Gustav Gerster GmbH & Co. KG and Bilsing Automation GmbH, Leibniz-Institut für Verbundwerkstoffe is researching on material and process technologies, that aim at enabling the variable bending of initially straight structural profiles made of fiber-plastic composites. In “Curved Composites” project (funded within the Zentrales Innovationsprogramm Mittelstand (ZIM)), profiles made of textile-reinforced acrylic resin are produced with established series processes, such as resin transfer molding. Acrylic systems, like the one in use, can be processed in the same way as thermoset resin systems, but once polymerization has taken place, they exhibit all the processing advantages, that are known from thermoplastics. In addition to formability and weldability, these include an improved recyclability in particular. Profiles with variable radii of curvature - and thus subsequent adaptation of the profile shape in respect to the load situation - can therefore be achieved by means of a downstream hot forming technique.

The design of the textile reinforcements is of great importance for the formability of FRP-profiles. While largely retaining their mechanical properties, these shall neither tear nor wrinkle during subsequent profile forming. In this context, Gustav Gerster GmbH & Co. KG is working on new textile concepts for fiber reinforcements, that can be further processed with high elongation and drapeability.

Leibniz-Institut für Verbundwerkstoffe is researching on process parameters, that ensure a safe and complete impregnation of these textiles with the acrylic resin. Permeability measurements and injection simulations accompany these investigations. In addition to developing an injection strategy for the acrylic resin system, the research focuses on the forming behavior of the textile reinforcements. The objective is to draw conclusions from the behavior of the textiles in the dry state about the extent of the forming capability of the composite.

The Chair of Forming Technology at University of Siegen (UTS) is responsible for the investigation of heating and bending behavior in the composite and the design of the bending process - taking heat input, forming behavior and the process kinematics into account. The investigations of the forming behavior of the profiles are carried out in close coordination with Bilsing Automation GmbH, which will develop a process-automated plant technology with a suitable handling unit for profile forming as part of the “Curved Composites” project.

The project “Curved Composites - Development of materials and processes for the production of subsequently formable profiles made of fiber-plastic composites; investigation of subsequently formable textiles and combination of these with subsequently formable resin systems in an injection process” is funded by the Federal Ministry of Economic Affairs and Energy (BMWi) on the basis of a decision by the German Bundestag (funding reference ZF4052336KI9).

Further informationen:

M.Sc. Alexander Faas
Scientific Staff Impregnation & Preform Technologies
Telephone: +49 631 2017 434

M.Sc. Jan Janzen
Scientific Staff Impregnation & Preform Technologies
Telephone: +49 631 2017 461


Figure 1: Reinforcement textiles for the production of bendable FRP-profiles (Gustav Gerster GmbH & Co. KG)

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