Experimental study of composite T-joints under tensile and shear loading

Abstract

An experimental study of a new type of composite T-joint with transverse stitching was conducted under tensile and shear loading. Fixtures were designed to load the T-joint specimens under simple support and fixed support boundary conditions, respectively. During experimentation, load–displacement and strain–load measurements were recorded and post-failure analysis was accomplished on failed specimens using optical microscopy. T-joint behavior under simple-support tension boundary conditions was shown to be linear up to initial failure. Specimens failed initially due to matrix cracking at the fillet region of the web-to-flange interface. Onset of ultimate failure was attributed to fiber insertion bridging leading to insertion breakage and pullout. The mechanical behavior under an applied shear load was marked by nearly linear behavior up to ultimate failure. Specimens fail by interfacial matrix cracking at the web-to-flange interface leading to T-joint catastrophic failure with complete separation of the web and flange.