Einfluss der Faserarchitektur auf die mechanischen Eigenschaften und die Schadenstoleranz von Geflechtlaminaten

Translated title of the contribution: The effect of fiber twisting on mechanical behaviour and damage tolerance of biaxial braided composites

Isabelle Jacqueline Berger

Research output: ThesisMaster's Thesis

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Abstract

The development of simulation models for aircraft components made with biaxial braided carbon fiber composites is limited by an inadequate material property database. Due to the braid properties of an individual design it is very unlikely to find existing data which exactly matches the actual configuration so that material data has to be determined by suitable material tests. This is why the aim of this thesis was to investigate the effect of fiber twisting on me-chanical properties and damage tolerance of a biaxial (±60°) braided carbon fiber epoxy composite. For this purpose specimens with twisted and untwisted yarns were loaded in tension and compression, all of these in both, longitudinal (0°) and trans-versal (90°) test direction. Additionally, standardized compression after impact tests and monotonic shear tests in longitudinal (0°) test direction were done. As expected, the results showed that the investigated tensile and compression properties for the transversal test direction were significantly higher compared to the lon-gitudinal test direction. Concerning the influence of fiber twisting an increase in ten-sile and compression modulus by loading in transversal test direction could be ob-served. For the longitudinal test direction tensile strength values showed a slight increase with increasing yarn twisting. Furthermore compression after impact strengths were found to be less affected by yarn twisting. Based on preliminary shear tests characteristic values of the investigated braid were determined using a modified H-notched specimen.
Translated title of the contributionThe effect of fiber twisting on mechanical behaviour and damage tolerance of biaxial braided composites
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
  • Wolfahrt, Markus, Co-Supervisor (external)
  • Pinter, Gerald Gerhard, Supervisor (internal)
Award date27 Mar 2015
Publication statusPublished - 2015

Bibliographical note

embargoed until null

Keywords

  • biaxial braided composite
  • fiber twisting
  • mechanical behaviour
  • damage tolerance

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