Study On The Mechanical Behaviors Of Viscoelastic Ring And Spherical Shell

In recant years, with the development of the voyage and aviation technology, the viscoelastic material has been applied more and more widely in engineering. This kind of material is time-dependence and temperature-dependence, it will relax and creep even at the normal temperature, so it may bring large error if one conducts the analysis of viscoelastic structure with the theory of classic elasticity. The thorough studies of the mechanical behavior and stability of a viscoelastic structure, which are an important content of the viscoelastic mechanics, have important theoretical and applicable value. Confined bucking means that the bucking configuration of a structure cannot be evolved freely due to presence the external obstacles. This kind of problem has many applications in industry, while the research papers about the confined buckling of viscoelastic structures are seldom seen.In this paper, Based on Boltzmann's viscoelastic model and assumed the system is elasticity at beginning, a system of pre-stressed double-rings, a system of pre-stressed double-bolls and a system of tpre-stressed double- rings under the state of constant temperature dispersion are analyzed. The solution of the problem is obtained analytically. The viscoelastic effects, such as creep and relaxation are investigated. The time evolution rules of displacement and pre-stressed load are also discussed. The influences of the geometrical sizes and the material parameters on the steady values of displacement and pre-stress load of the system state are analyzed. Finally, the problem is expanded to the single layer viscoelastic system with the rigid restriction.Besides, based on Boltzmann's viscoelastic model and assumption of the elasticity for the initial structure, the critical bucking load and the stability of the solution are investigated by use of assuming mode method, Galerkin method and numerical computation. The system of the confined bucking mode of a viscoelastic ring is developed. It is found that not only instantaneous critic load exists, but also a durable critic load for the bucking of viscoelastic ringing under uniform pressure. While only does an instantaneous critic load exists for the confined bucking mode of a viscoelastic ring when the temperature difference is constant. At last, based on numerical method, further investigations are carried out into critic load, bucking configuration and the influences of structural size and material parameter.The present studies are very valuable to the mechanical behavior and life prediction of viscoelastic structures.