Charakterisierung eines im RTM-Prozess hergestellten CFK-Metall-Leichtbauwerkstoffes

Translated title of the contribution: Characterization of a CFRP-metal hybrid material produced in a single-step RTM-process

Dominik Brandstetter

Research output: ThesisMaster's Thesis

Abstract

The key to the success of lightweight construction concepts is building up hybrid structural elements using different materials. The intention is to combine the advantages of the single components, as well as to compensate for their disadvantages. The production procedures of such hybrid materials are only economically viable if there is a high level of automation and the cycle times are short. This is the aim of project "HybridRTM". Among other things, the project attempts the production of an assembly carrier for the rear flap of a car made out of carbon fibre reinforced polymer (CFRP) and metal in a one-step process. In this process, the assembly carrier (with his metallic inserts and onserts) is manufactured by means of Resin Transfer Moulding. This thesis investigates this hybrid material according to the maxims of material testing. The experiments targeted the mechanical, thermal and thermo-mechanical characteristics of the material at -40 °C, 23 °C and 90 °C. In order to validate these values with theoretical models, each component was characterized individually. Three equally thick CFRP laminates (V1, V2 and V3) of different fabric types were investigated. V1, being a combination of V2 and V3, was also used for the hybrid material. The metal type was a microalloyed flat steel with high yield strength. The expected temperature dependence of the hybrid material was confirmed in all tests. With increasing temperature the modulus in fiber direction acquired in tensile and bending tests decreased by up to 20 %. In (±45) orientation the level dropped by up to 50 %. The temperature sensitivity of the interface was examined by apparent interlaminar shear strength and interlaminar fracture toughness tests. Both test methods showed a certain correlation in temperature sensibility. Yet, the mode I tests reacted stronger to the temperature rise and showed a drop of the level of up to 60 %. The results also showed that at a very low temperature the interface between the CFRP and the metal has a very strong adhesion. Because of that, cohesive failure appeared in the CFRP laminate. At high temperature, however, pure adhesive failure was observed. The thermal analyses proved an about 70 % increase in heat conductivity in thickness direction with a rise in temperature. The thermal expansion coefficient in fiber direction was five to six times lower than in thickness direction.
Translated title of the contributionCharacterization of a CFRP-metal hybrid material produced in a single-step RTM-process
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
  • Stelzer, Steffen, Supervisor (internal)
  • Pinter, Gerald Gerhard, Co-Supervisor (internal)
Award date16 Dec 2016
Publication statusPublished - 2016

Bibliographical note

embargoed until 11-11-2021

Keywords

  • RTM
  • Resin Transfer Moulding
  • carbon
  • carbon fibre reinforced plastic
  • CFRP
  • composite
  • fibre reinforced plastic
  • FRP
  • lightweight construction
  • hybrid
  • material testing
  • adhesives
  • metal
  • resin

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