Study On Dynamic Mechanical Properties Of Low Shear Modulus Silicone Rubber-base Compounding Materials And Finite Element Application

Earthquakes are natural disasters that human have to face,and the consequences are devastating.The earthquake brings the instability to the safety degree of human living environment,it's also hard to ignore the direct and indirect post-disaster Loss.Using seismic isolation technology to increase the seismic capacity of building structures is currently an important means to reduce earthquake losses.As seismic isolation device,the lead rubber bearings have been widely recognized and applied.Constantly developing new lead rubber bearings with high quality become the trend of seismic isolation technology research.Rubber material is the main factor to influence the hysteretic energy dissipation behavior of lead rubber bearings.In theory,the low modulus rubber material can obtain more plump hysteretic energy dissipation behavior.In the design of lead rubber bearing,now we generally adopts the static test data to calculate the yield shear force,initial shear stiffness and post-yield stiffness.Then the third party sampling inspection and check the accordance with the requirements of the error,and it can be directly applied to engineering practice.This can not only cause a lot of waste of testing resources,but also unable to explore the real performance of the lead rubber bearings under the seismic excitation.In view of these problems above,combined with the current national standards,this thesis analysis and discuss the research of the lead rubber bearings based on a newly developed low modulus silicone rubber-base compounding materials.The thesis is mainly composed of three sections that are arranged as following:1.Testing the dynamic mechanical properties of newly developed low modulus silicone rubber-base compounding materials.Discussing effects of strain amplitude and loading frequency on dynamic mechanical properties under sinusoidal displacement load.And all these tests discover that this material have both characteristics of hyperelastic and viscoelastic.Subsequently,this paper organizes and sums up dynamic mechanical properties changing regularity of this material,and also quantifies some material properties According to the actual situation of earthquake excitation,determining the main mechanical properties is hyperelastic when medium or small earthquakes occurs.2.Appling both hyperelastic theory and viscoelastic theory to describe the dynamic mechanical properties of this silicone rubber-base compounding materials.The mathematical expressions of hyperelastic Bouc-wen model and viscoelastic fractional order Kelvin-Voight model are established respectively by using Simulink tools.Among that,a new shortcut method for identifying simplified Bouc-wen model is proposed,which avoids the instability of the identification result in the traditional identification method,and the problem of locally optimal solution.3.Appling FEM theory and Abaqus/CAE software to set up a three-dimention model of lead rubber bearing based on this silicone rubber-base compounding materials.In order to simplify the calculation,Money-Rivlin model is used instead of Bouc-wen model,and the dynamic behavior of the LRB under sinusoidal displacement load is studied.Finally,through observing the changing regularity of internal force,it is found that the contact part of the material component in the lead rubber bearing is the weak link.