Study On The Visco-hyperelastic Behavior Of Polysiloxane Rubber And Mechanical Behavior Of Porous Structure

Polysiloxane rubber is a kind of typical polymer material which is usually colorless and transparent.The molecular structures of Polysiloxane rubber consist of Si-O bonds as the main chain and organic groups directly connected to the silicon atoms,respectively.Owning to the outstanding hyperelastic property derived from the intertwined molecule chains,the polysiloxane rubber is widely used for fabrication of damping structures and stretchable electronics.In engineering application,it is crucial to precisely describe the visco-hyperelastic behavior of materials under dynamic and large deformation for the design of polysiloxane rubber based damping structures and flexible electronic devices.In addition,porous structural materials have excellent shock absorption performance and great potential in electronic materials due to its unique internal structure.However,structural geometric parameters have a great impact on the shock absorption performance of porous materials.Therefore,it is necessary to optimize the geometric parameters of the porous structure to achieve the requirements.The mechanical behavior of polysiloxane rubber is studied by the methods of theoretical,experimental and numerical simulation analysis as well as the optimization of the geometric parameters of the porous structure.The main research contents and results are summarized as follows:In the aspect of constitutive model,for the first step,the hyperelastic behavior and viscoelastic effect are decoupled to propose the basic forms of the visco-hyperelastic constitutive model.Secondly,the hyperelastic model of the material is established based on quasi-static tests,respectively.Then,the strain rate effect is quantified by Hopkinson pressure bar tests,based which the viscoelastic model is established.Accordingly,the nonlinear visco-hyperelastic constitutive model is finally proposed by combing the two decoupled models.Besides,the proposed visco-hyperelastic constitutive model is used to simulate the drop-weight impact behavior of polysiloxane rubber specimens by finite element method.In the aspect of porous structural materials,firstly,the direct writing printing technology is used to print the polysiloxane porous materials.Secondly,the static and dynamic mechanical properties are studied by uniaxial compression test and drop-weight impact test.Besides,the reliability of the viscoelastic constitutive model is verified by numerical analysis method.Finally,the influence of structural parameters on the mechanical properties of the porous materials is studied by finite element method.Based on the above research,visco-hyperelastic constitutive model of polysiloxane rubber under large strain and large strain rate is established.The influence of structural geometric parameters on the mechanical properties of polysiloxane porous materials is studied.The energy absorption efficiency diagram and energy absorption diagram are established.The results obtained in this paper provide a theoretical and applied basis for the optimal design of polysiloxane rubber based shock absorption structure and flexible electronic devices.