On the Linear Viscoelasticity of Thin-Walled Laminated Composite Beams

An analytical model to predict the linear viscoelastic behavior of thin-walled laminated fiber-reinforced plastic (FRP) composite beams is presented. Using the correspondence principle, this new model integrates micro/macro-mechanics of composites and mechanics of thin-walled laminated beams to perform beam. analyses in the Laplace or Carson domains. The analytical expressions for beam relaxation coefficieQts are obtained. Using a collocation method, the flexural creep behavior of beams in the time domain is numerically solved. Predictions by the present model are compared favorably with experimental data for glass fiber-reinforced plastic structural laminates under tension and a box-beam under bending. The influence of beam fiber architecture and fiber volume fraction on the linear viscoelastic response for a wide-flange beam is examinedto show that this model can be efficiently used in the flexural creep analysis and design of FRp· structural shapes. *Author to whom correspondence should be addressed. Journal of COMPOSITE MATERIALS, Vol. 34, No. 01/2000 0021-9983/00/01 0039-30 $10.00/0 © 2000 Technomic Publishing Co., Inc. 39 40 PIZHONG QIAO, EVER 1. BARBERO AND JULIO F. DAVALOS On the Linear Viscoelasticity of Thin-WaUed Laminated Composite Beams 41