On the linear viscoelasticity of thin-walled laminated composite beams

An analytical model to predict the linear viscoelastic behavior of thin-wal led laminated fiber-reinforced plastic (FRP) composite beams is presented. Using the correspondence principle, this new model integrates micro/macro-m echanics of composites and mechanics of thin-walled laminated beams to perf orm beam analyses in the Laplace or Carson domains. The analytical expressi ons for beam relaxation coefficients are obtained. Using a collocation meth od, the flexural creep behavior of beams in the time domain is numerically solved. Predictions by the present model are compared favorably with experi mental data for glass fiber-reinforced plastic structural laminates under t ension and a box-beam under bending. The influence of beam fiber architectu re and fiber volume fraction on the linear viscoelastic response for a wide -flange beam is examined to show that this model can be efficiently used in the flexural creep analysis and design of FRP structural shapes.