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An expression is obtained for the dissipated energy of a linear viscoelastic body with a continuous relaxation spectrum in the case of an arbitrary law of variation of the strains with time. Lower bounds for the total and dissipated energies are constructed by the method proposed in [3]. The calculated values of the dissipated energy are compared with experiment.

The mechanical properties of polymers have been investigated at medium impact velocities. The various experimental methods of constructing stress-strain diagrams are compared.

A procedure is proposed for calculating relaxation spectra from experimental data on uniaxial tension over a broad range of strain rates. The relaxation spectra are calculated for low-density polyethylene and for a fabric-reinforced glass laminate in three directions relative to the reinforcement.

Constraints on the coefficients of the equations of state of anisotropic linear viscoelasticity are obtained using the positive definiteness of two quadratic forms—the potential energy and the energy dissipation rate.