Abstract (EN):
Machines capable of individually controlling fibre tows and placing them onto the surface of a laminate with curvilinear topology are available nowadays. Due to the variation of properties along their surface, such structures are termed variable-stiffness composite panels. Experimental research demonstrated that properly designed tow-steered panels buckle at higher loads than traditional straight-fibre laminates. Also, numerical analyses by the authors demonstrated that first-ply failure of these designs is remarkably postponed. The focus of this paper is to extend those analyses into the postbuckling progressive damage behaviour and final structural failure. A user-developed continuum damage model implemented in the finite element code ABAQUS® is employed in the characterisation of damage initiation and propagation. As with damage initiation, failure of curvilinear-fibre panels is remarkably postponed as compared with straight-fibre laminates. Tow-steered panels also show to be more tolerant to notches than traditional laminates. By taking into account the residual thermal stresses, not only predicted and experimented buckling loads show remarkable agreement but also predicted final failure loads of tow-steered panels in postbuckling are within 12% of the experimental results.
Language:
English
Type (Professor's evaluation):
Scientific