Postbuckling behaviour of a blade-stiffened composite panel loaded in uniaxial compression

The postbuckling behaviour of a panel with blade-stiffeners incorporating t apered flanges was experimentally investigated. A new failure mechanism was identified for this particular type of stiffener. Failure was initiated by mid-plane delamination at the free edge of the postbuckled stiffener web a t a node-line. This was consistent with an interlaminar shear stress failur e and was calculated from strain gauge measurements using an approximate an alysis based on lamination theory and incorporating edge effects. The criti cal shear stress was found to agree well with the shear strength obtained f rom a three-point bending test of the web laminate. (C) 2000 Elsevier Scien ce Ltd. All rights reserved.