Numerical Analysis Of Energy Dissipation And Vibration Reduction Performance Of STF Materials

Shear Thickening Fluid(STF)is a new type of smart material,which characteristic is the viscosity changes nonlinearly with the change of shear rate,and some stages show a "power law"growth trend.After the shearing effect is applied to it and the critical shear rate is reached,the state of the STF is transformed from a fluid state to a solid-like state,and a large amount of energy is absorbed during this transformation process.Therefore,STF is widely used in vibration damping,earthquake resistance,human body protection and other fields.The current research on STF focuses on the properties of materials,but there is serious lack of practical research in the field of engineering vibration reduction and energy consumption.This article mainly studies the basic characteristics of STF materials through the preparation and performance testing of STF materials,and is based on two different Constitutive energy dissipation models,by applying these two models to energy-consuming STF composite components in the field of civil engineering and mechanical vibration reduction and noise reduction,through finite element analysis,the energy dissipation and vibration reduction characteristics of STF materials based on different viscoelastic constitutive models are demonstrated.Based on the above thoughts,the main work of this article is as follows:1.In this paper,nano-SiO2 is used as the dispersed phase particles,polyethylene glycol(PEG)is used as the dispersion medium,and the STF material is prepared by a combination of ultrasonic dispersion and mechanical stirring.At the same time,steady-state performance analysis and dynamic performance analysis of the prepared STF material are carried out.The analysis results show that:(1)In the steady-state performance test,the STF material formulated in this paper has good shear thickening,thixotropy,good steady-state performance,and conforms to the basic characteristics of shear thickening fluid;(2)The dynamic performance of STF with a mass fraction of 30%and a particle diameter of 20nm through frequency scanning and strain scanning,the storage modulus and energy dissipation modulus under each state are obtained,indicating that the shear thickening fluid has excellent vibration reduction effect.2.According to the requirements of low-frequency and high-frequency energy dissipation and vibration reduction of STF materials,combined with the extrusion energy dissipation model and vibration energy dissipation model based on the viscoelastic constitutive relationship and the performance of the formulated STF material,the establishment of the above two Simplified numerical analysis models were established respectively:(1)Based on the extrusion energy dissipation model of extrusion or large-scale shear deformation,the paper uses the spring model as the prototype,and establishes the STF unit body through the parameter setting of stiffness and damping.Set the initial viscosity and the maximum viscosity to determine the stiffness,and determine the damping by setting the relationship ratio between the storage modulus and the energy dissipation modulus,and simulate the nonlinear force change of the STF system,thereby establishing a more reasonable STF material unit.(2)The vibration energy dissipation model takes the frequency domain viscoelastic body as the model for parameter setting.Due to the lack of stress-strain relationship in STF materials,the frequency domain response of dynamic viscoelasticity is used for analysis.Taking the storage modulus and dissipation modulus of the STF material as the basic parameters,they are set in a dimensionless manner in the finite element,so as to connect the STF and the frequency domain viscoelastic material to achieve the purpose of simplifying the STF material unit.3.Based on the extrusion energy dissipation model,the STF composite steel beam is established.Through numerical simulation,the low energy dissipation capacity of the composite steel beam under low-cycle reciprocating load is analyzed.The analysis results show that:(1)The Jeffreys model with multiple Hertz models in parallel is more consistent with the spatial continuity of the squeeze energy dissipation model.(2)Perform a finite element simulation analysis on the STF composite beam model,demonstrate the damping characteristics of STF materials and composite beams through the energy method,and define the effective damping parameter S of the STF composite system to meet engineering calculation requirements.(3)Different thicknesses of materials and different variable damping affect the effective damping parameters of STF composite beams.4.Based on the vibration energy consumption model,STF is used to reduce the vibration and noise of the communication cabinet by simplifying the settings of the storage modulus and energy dissipation modulus and the viscoelastic parameters in the frequency domain of ABAQUS.Through the finite element harmonic response analysis,a comparative analysis of the vibration and noise reduction of the cabinet under various working conditions shows that:(1)When STF is used for high-frequency vibration,it has a good effect on the vibration and noise reduction of the communication cabinet.,which meets the test requirements;(2)The effect of arranging STF material on the vertical side plate is better than that of arranging it on the transverse diaphragm,which provides a test design and a strong theoretical basis for the subsequent project;(3)Increasing the thickness of the STF material within a certain range can enhance the structure’s vibration and noise reduction effect.At the same time,the heat energy generated by the cabinet is absorbed by the STF system,which can enhance the energy absorption characteristics.