An Investigation on Thermomechanical Flexural Response of Shape-Memory-Polymer Beams

Abstract

In this paper, the predictions of different beam theories for the behavior of a shape memory polymer (SMP) beam in different steps of a thermomechanical cycle are compared. Employing the equilibrium equations, the governing equations of the deflection of a SMP beam in the different steps of a thermomechanical cycle, for higher order beam theories (Timoshenko Beam Theory and von-Kármán Beam Theory), are developed. For the Timoshenko Beam Theory, a closed form analytical solution for various steps of the thermomechanical cycle is presented. The nonlinear governing equations in von-Kármán Beam theory are numerically solved. Results reveal that in the various beam length to beam thickness ratios, one of the beam theories provides the most accurate results. In other words, employing the Euler–Bernoulli Beam Theory for developing the governing equations, especially in the large and small beam length to beam thickness ratios, leads to erroneous results.