Vibration Of Viscoelastic Plate Resting On Viscoelastic Foundation Based On ANSYS

The elastic thin plate and thick plate resting on viscoelastic foundation have been widely applied in engineering area.Since most materials possess of viscoelasticity,many researches have studied the plates with viscoelastic foundation by approximately processing the viscoelastic material into elastic material,which can satisfied the engineering demand in some condition.However,in some cases the viscoelasticity must be considered so that it can meet the precision of engineering application.Because of the complexity of the dynamic equation of viscoelastic thick plate and the difficulty of boundary condition,it is impossible to get the analytical solution of viscoelastic thick plate resting on viscoelastic foundation,and no previous work has been done on the relevant theoretical research.In this thesis,the vibration properties of viscoelastic plate resting on viscoelastic foundation are analyzed based on the finite element method and the ANSYS software,then the effect of thickness of plate on the vibration performance is discussed.Since the viscoelastic material is a sort of rate-dependent material,the complex damping theory is used in ANSYS to solve the vibration problem and only the harmonic response analysis can be conducted.Therefore,the constitutive equation of viscoelastic material is disposed so that the modal analysis and transient dynamic analysis can be achieved from ANSYS.In chapter 1,the fitting formula of experiment results of dynamic modulus is derived,and the parameters of viscoelastic materials are obtained.In chapter 2,considering the ANSYS is unable to carry out the modal analysis and the transient dynamic analysis of viscoelastic material in harmonic loads,a solution is proposed by processing the viscoelastic structure into elastic structure with large damping,and some relevant theoretical basis are provided.In chapter 3,three-dimensional models of an elastic plate resting on viscoelastic foundation,a viscoelastic plate resting on elastic foundation and a viscoelastic plate resting on viscoelastic foundation are established in ANSYS to get the modal analysis respectively,comparing results with each other,the effect of thickness of plate on the vibration performance is discussed.Then the influence of modulus ratio of foundation to plate on dynamical characteristic of structure is investigated,which provides theoretical basis and reference for engineering application.In chapter 4,harmonic response analysis and transient dynamic analysis under sinusoidal load for viscoelastic plate resting on viscoelastic foundation are performed.Based on outcomes,the effect of thickness of plate on the sensitivity frequency,dynamic displacement and dynamic stress are discussed.In chapter 5,summaries of this dissertation are concluded.