Three-dimensional X-ray tomography for multiscale characterization and fatigue damage investigations of composites for wind turbine blades. - DTU Orbit
Key mechanical properties of the load carrying composite laminates in
wind turbine blades are the stiffness, fatigue resistance and the
compression strength. While the overall design criteria for glass fiber
composites mainly are stiffness driven, it tends to be more fatigue and
compression strength driven when using carbon fiber or glass/carbon
hybrids. Using lab-source x-ray computer tomography in connection with
ex-situ fatigue testing of quasi uni-directional composites, local fiber
failure has been followed. The material investigated is typical
non-crimp fabric used in wind turbine blades. The fatigue damage
evolutions is studied during tension/tension, tension/compression and
compression/compression fatigue. It is found that the location of the
tension/tension (R=0.1) and tension/compression (R=-1) fatigue damage
are controlled by the bundle architecture, while the
compression/compression (R=10) show up as small shear cracks located in
the matrix between the fibers. In addition to fatigue damage
investigations, the fiber architecture inside the fiber bundle and the
fiber bundle architecture is studied.......
