Experimental failure investigation of pull-off tests of single T-stiffened composite specimens

This paper investigates the initiation and progression of interlaminar failure complying with characteristic postbuckling deformation patterns using single T-joint specimens with different geometric definitions and laminate disposals. The analysis herein conducted addresses the role of these aspects regarding the characteristic failure behavior in terms of: (i) damage initiation location, and (ii) progression path within the specimen. A thorough qualitative discussion concerning the damage initiation and subsequent progression path at the skin-stringer joint is supported by the development of a simple analytical model based on the Classical Laminate Theory denominated as 3-spot-joint model. These results provide a valuable insight into the principal mechanisms that govern such interlaminar damage events, which usually provoke the structural collapse in actual carbon fiber reinforced polymer composite stiffened panels.