Thermomechanical Dissipation Analysis of Thermoviscoelastic Solids by Finite Elements

摘要

The thermomechanical dissipation function for thermorheologically simple materials, which is derivable from a rational theory of thermodynamics, is examined for the special case of oscillatory motion. It is demonstrated that in most practical applications the dissipation function can be adequately represented by the expression for the total work. Dissipation effects in thermoviscoelastic materials are discussed. A solution to a boundary value problem involving twisting of a solid circular cylinder of viscoelastic material with temperature dependent material properties is obtained by use of the finite element method. Two dimensional heat transfer is permitted. The theoretical results are compared with experimental measurements of the temperature in a solid polyurethane cylinder being twisted in an oscillatory manner. The comparisons indicate that isothermal dissipation theory overestimates the amount of heat generated while the thermorheologically simple theory underestimates the heat generated. In the frequency range of 100-1000 cpm and at small strains, temperature changes of about 30F were recorded. (Author)