Paper number 354
|DELAMINATIONS UNDER PURE MODE II LOADING SHOW SIGNIFICANT LOCAL MODE I BEHAVIOUR|
Isabelle Paris and Anoush Poursartip
Composites Group, Department of Metals and Materials Engineering The University of British Columbia, Vancouver, B.C., Canada, V6T 1Z4
http://www.composites. ubc. ca/
|Summary||In order to study delamination crack tip behaviour, several specimens have been tested under pure mode II loading inside a scanning electron microscope. One of the most interesting findings is the presence of crack opening displacements, even though the global loading has been independently confirmed to induce only pure shear. COD profiles have been measured for different applied mode II strain energy release rate values and their magnitude is very significant. The local crack opening is the result of the crack faces being moved apart as surface features slide over each other, and therefore the amount of opening varies with the surface roughness. For this reason, there is less opening when the crack is grown from an insert than when it has already been grown beyond the insert. Moreover, the variability in the amount of mode I opening can explain the higher scatter in GIIc data in the literature.
||Keywords|| fracture mechanics, delamination, in-situ, crack tip behaviour, crack opening displacement, crack shear displacement, Scanning Electron Microscope (SEM).
Theme : Mechanical and Physical Properties ; Fracture Mechanics and Failure
[ HOME ] [ BACK ]