| Shear thickening fluid（STF）is a highly concentrated particle suspension.Under proper shear,its viscosity will rise rapidly with the increase of shear rate,and this increase has the characteristics of non-linearity and fast response.In recent years,with the deepening of theoretical research and the development of experimental technology,researchers have made significant progress in many fields such as STF micro-mechanism research,material manufacturing,and application.How to further optimize the performance of STF and make it better used in practical engineering applications has become an increasingly concern for researchers.To this end,this paper first prepares STF materials and optimizes their performance,then establishes a viscosity model based on the non-linear characteristics of STF material performance,and designs a torsional STF damper structure.It lays the foundation for the preparation of high-performance STF materials and the further development of high performance STF energy-consuming and vibration-damping devices.In order to obtain STF,STF and its performance optimization system were prepared,and its rheological properties were studied.First,shear thickening fluid was prepared,and then its rheological properties under differen t conditions were tested,and the influence of changes in different parameters（dispersed phase concentration,ambient temperature）on its rheological properties was analyzed.On this basis,the monodisperse STF system prepared by the treatment of high-performance structural ceramic material Si3N4 to obtain an optimized STF performance system,and the mechanical properties under steady and dynamic conditions were tested and compared with the rheological test results of the monodisperse STF.The results show that the addition of Si3N4 can effectively improve the mechanical properties of the Si O2-based monodisperse STF and reduce the temperature sensitivity of the original STF.In order to better describe the viscosity characteristics of the shear thickening fluid,a constitutive relationship model was established.Based on the phenomenological theory,the power function,logistic function and exponential function are used to represent the three different characteristic regions of the STF viscosity curve,and a shear thickening fluid constitutive relationship viscosity model is established.Through the viscosity test data of the STF under different materials,different mass concentrations and different temperatures,the Levenberg-Marquardt algorithm was used to fit the specific values of the model parameters to verify the rationality of the model.After preparing the STF and establishing the viscosity model,an experimental study on the mechanical properties of the STF damper was conducted.Based on t he non-linear mechanical performance characteristics of STF,the torsional damper structure is adopted to design and manufacture the torsional STF damper,and the theoretical model of the STF damper is established.By applying static loads with different rotation speeds,the influence of loading rotation speed and loading time on the mechanical properties of torsion STF damper is analyzed.The results show that the mechanical properties of the torsion-type STF damper change significantly with the change of loading speed and loading time.Using the mechanical performance test results,the validity of the theoretical model of the STF damper is verified.The use of a multi-phase STF performance optimization system can further improve the sensitivity of the damper to excitation,and can provide a greater output damping force under a shorter excitation time and a lower loading rate. |
