Experimentelle Basischarakterisierung einer neuen Fügetechnologie mit erhöhter Schadenstoleranz für endlosfaserverstärkte Kunststoffe

Translated title of the contribution: Experimental investigation of new joining technologies for enhanced damage tolerance of fibre reinforced polymers

Thomas Unger

Research output: ThesisMaster's Thesis


In recent years there has been a growing trend towards the heightened utilization of structural components made of endless fibre reinforced polymers. The continuous development of production technologies and the increasing degree of automation, simultaneously reducing costs, lead to an increased application of this technology in the energy, the automotive and the aviation industry. Highly durable connections, which fullfill the conditions decreed by the “fail safe” principle, can only be implemented with the present joining technologies like riveting, screwing and adhesive bonding at the cost of high material expenditure. This paper focuses on a new joining technology in regards to optimized specific joint strength between the structural components made of carbon fibre reinforced polymers (CFRP). For joining, metal insert layers with vertical pins, composed of steel or titanium, were used. These metal inserts have been placed in the overlap area between the CFRP laminates. To allocate the specific processes, responsible for the mechanical failure of the connections, the test pieces were tested with static load. The quality of those experiments was further enhanced via the testing of the interfaces under different load scenarios. To research the delamination characteristics of this new joining technology, double cantilever beam (DCB), end notched flexure test pieces (ENF) with metal inserts composed of steel or titanium and different surface pretreatments were produced. Experiments under pure mode I and II loading conditions on test specimens with titanium inserts displayed a higher energy release rate G, than those with steel inserts. The different surface pretreatment had an impact on the crack growth behavior, but the influence was not as substantial as the selection of the base material. To review the reinforcement of the connections with z-pins, single lap shear (SLS) and double lap shear (DLS) were chosen as test specimens. In this study, three different pin formations, which reinforce the overlap area, were analyzed. The one with the two pin rows on each end of and the arrangement with pins all over the overlapping area were able to bear the highest shear stresses. The design with the pins at the corners of the overlapping area provided the smallest values. Additionally, an optical system was used to measure the strains on the interface. With this information, the failure behavior was evaluated. The exact type of failure mechanism was allocated through the characterization of the fracture surface.
Translated title of the contributionExperimental investigation of new joining technologies for enhanced damage tolerance of fibre reinforced polymers
Original languageGerman
  • Pinter, Gerald Gerhard, Supervisor (internal)
  • Stelzer, Steffen, Co-Supervisor (internal)
Award date22 Mar 2013
Publication statusPublished - 2013

Bibliographical note

embargoed until 25-02-2018


  • CFRP
  • z-Pin
  • delamination
  • damage tolerance
  • Double Lap Shear
  • Single Lap Shear
  • Double Cantilever Beam

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