Inge Lehmanns Gade 10
bygning 3210, 05.093
8000 Aarhus C
PhD project description:
Fiber composites loaded in tension have high stiffness and strength, but when loaded in compression the critical stress is considerably lower than in tension. Structural components loaded in bending are exposed to both tension and compression and since the critical stress is lower in compression this is the failure mode which should be used as a design load.
Several studies have been made in mapping the different failure modes of fiber composites in compression. The most frequently observed failure is do to plastic microbuckling which is a material instability and results in kink band formation. These are bands of material where the fibres inside the band have rotated relative to fibres outside the band. Kink band formation as a failure mechanism is observed in unidirectional fibres as well as in multi layered composites with different layups inside the individual layers.
The critical stress for kink band formation is known to be sensitive to structural imperfections such as misalignments of the fibres relative to the load direction. This make theoretical investigations of kink band formation challenging as they must involve full, non-linear finite element simulations allowing for all possible non-linear behavior of the constituents as deformation evolve.
Project title: Modelling of Failure in Composite Materials
Project period: May 2016 - Jan 2020
Superviser: Prof. Henrik Myhre Jensen