One-dimensional models and thermomechanical properties of solids

We use open-ended chains of oscillators, like those introduced by Fermi, Pasta, and Ulam, to mimic thermomechanical properties of crystalline solids, such as thermal expansion and the change of elasticity and quality factors with temperature. We employ molecular dynamics and theoretical arguments, separately. Features of real solids are reproduced, such as the positiveness of the coefficient of thermal expansion and the decrease of the modulus of elasticity and of the quality factor with temperature. The results depend strongly on the interparticle potential at energy levels much higher than the average energy of the chain, with the Lennard-Jones potential yielding the most realistic cases.