Vasilij K., Igor S., Jaroslav Z.

Plastic dampers provide an effective defense of structures, technological equipment, pipelines etc. from extremal loading among them the cyclic one is very important. Principle of it operating is based on essential dissipation of mechanical energy during inelastic deformation of metallic damper components. Investigation of the cyclic problem within properly formulated viscoplastic dynamic statement is very difficult. In the paper presented a simplified government equations of the problem based on complex moduli approach is justified. The value sought are amplitudes of displacements, stresses, total and inelastic strains as well as selfheating temperature. Complex moduli are calculated either by the methods of harmonic linearization or using experimental cyclic diagrams and hysteresis loop data. Because of the material nonlinearity the complex moduli are the function of appropriate strain or stress invariants. Bodner-Partom viscoplastic model is used as a basis complete one. An accuracy of simplified approach is evaluated by comparison of solutions obtained both in simplified and complete formulations. The problem of vibrations of such dampers as multilayered beams and discs are considered numerically with using of finite element method. Excellent adjustment of results relatively dissipation rate, stored energy, amplitudes of displacements, stresses, total and inelastic strains, loss factor as well as selfheating temperature is established.