Failure analysis of reinforeced glulam beams by a layer-wise theory

A progressive failure analysis for glulam beams reinforced with glass fiber-reinforced plastic (GFRP) composite materials is presented in this paper. The failure analysis is accomplished with a Beam finite element with Layer-wise Constant Shear (BLCS), which can accurately compute stresses on each layer for any type of laminate. The progressive failure algorithm makes use of material degradation factors (DFs) and the Tsai-Wu and Maximum Stress Failure criteria. This is the first study that accounts for tensile, compressive, and shear failures of laminae and finger joints in glulam-FRP beams. Guidelines are given for the selection of material DFs, and both load- and displacement-controlled schemes are used to trace the response to failure. The experimental results of full-scale (0.1 x 0.34 x 5.79 m) yellow-poplar glulam beams reinforced with pultruded GFRP correlate closely with predicted values. The present model accurately predicts ultimate load and displacement of glulam-GFRP beams and qualitatively describes the failure accumulation and propagation through the laminate.