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Lecture

Damage analyses of cohesive layer of intrinsic aluminum CFRP hybrid composites produced in high pressure die casting with polymer based decoupling layer

Thursday (09.11.2017)
10:35 - 10:55
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Combining aluminum and carbon fiber reinforced plastic (CFRP) has been a key focus in realizing lightweight concepts. The direct joining of these two materials is problematic, though, due to their electrochemical intolerance and the resulting corrosive degradation. The joining technology therefore is at the center of this challenge. In the current work this is to be achieved in a single-step primary shaping process, avoiding conventional joining techniques like adhesive bonding or riveting. To this end, CFRP structures are to be recast with aluminum, creating an electrochemically decoupling layer between the two materials. This decoupling layer can be considered as a key factor for realizing hybrid composites. It also needs to have high process reliability and be long-term and mechanically stable. Polyetheretherketone (PEEK) thermoplast was identified as a suitable material for that purpose, given its stability at high temperatures and electrochemical insulation effect. To under¬stand the failure of the cohesive layer and to find a reliable way to predict the strength of it, finite element simulations are used. With a linear elastic FE model, a stress analysis of the cohesive layer is made to design specimens with different fracture behavior. Specimens with an adherent thickness from 2.5mm up to 10mm for aluminum and 2.5mm for CFRP have been produced with different thicknesses from 0.05 to 0.15 mm of the cohesive layer. Experimental test were carried out on different specimen geometries. The results, observed in the experimental test were taken to identify the parameters of the employed cohesive zone model (CZM). The force-displacement-recordings from the experimental tests are in good agreement with the numerical results.

Speaker:
Adrian Struß
University of Bremen
Additional Authors:
  • Prof. Dr. Thomas Hochrainer
    TU Graz