Ostos O. Coupled thermomechanical behaviour of prestressed elastomeric structural elements under cyclic loading

The thesis is devoted to solving the problems of forced resonant vibrations and dissipative heating of hinged viscoelastic elastomeric rectangular plates and cylindrical shells with account of membrane prestresses. The problem statement is based on the standard Kirchhoff-Love hypotheses and concept of complex moduli that are used to describe the cyclic response of a viscoelastic material to harmonic loading. Mechanical stationary and thermal behaviour of both steady-state and transient thermal response of plate and shell are investigated. As a typical representative of elastomeric materials in the work under conditions of harmonic loading polyethylene was chosen. Weller diagrams are used to estimate the endurance at overcritical load values for different prestressing values, which relates the load level to the number of cycles of vibrations before failure. These diagrams are constructed for different values of overcritical loading and prestressing. It is established that the prestresses significantly affect the performance of the structure, shifting the AFC, i.e. changing the dynamics of the problem, and shifting the Weller diagrams to or from the origin.