Friction Vibration Characteristics Of Rubber Materials And Vibration Suppression Mechanism Of Textured Surface

Rubber material is a kind of high elastic polymer material,which plays an important role in a variety of high precision mechanical systems.However,due to its characteristics of low elastic modulus and high surface adhesion energy,obvious frictional vibration phenomenon will occur when it contacts and slips with hard surface.The surface texture design of rubber material is an effective method to suppress friction vibration,but the mechanism of vibration suppression is not clear.Therefore,the study of friction vibration characteristics of rubber materials and the vibration suppression mechanism of textured surface is an important subject to be solved in the development of high precision mechanical systems.PDMS samples with micron surface texture are prepared by photolithographictransfer technique,and the results of confocal microscopy confirmed that the prepared samples met the design requirements.The tensile mechanical properties and viscoelastic properties of rubber materials are characterized by uniaxial tensile test and dynamic mechanical test(DMA),respectively.The Yeoh hyperelastic constitutive model and Prony series model are established to accurately characterize the mechanical properties of rubber materials.The interfacial tensile strength and shear strength of rubber materials are obtained by testing the interfacial strength,and the adhesion energy density of rubber materials is obtained by using JKR theory.The results showed that the interface strength and adhesion energy density increased with the increase of the ratio of PDMS materials.A three-dimensional friction simulation model based on Coulomb's friction law is established,and in-situ high-speed friction experiments are carried out.The simulation and experimental results elucidate the nucleation and propagation process of Schallamach wave.The first Schallamach wave forms on both sides of the contact area when the rubber material is rubbed on a smooth surface.In the process of propagation,the velocity and wavelength of the wave show the law of increase-reduce-increase,and the amplitude gradually increases.The appearance of Schallamach wave cause friction and vertical force fluctuations.There are differences on time for the peak of friction and vertical force,while the trough is synchronous.And the maximum contact area is synchronized with the peak of vertical force.A three-dimensional friction model of rubber material is established based on the principle of adhesion and peeling,and the surface deformation and friction fluctuation characteristics of the material are obtained when the irregular Schallamach wave is generated.The effects of viscoelasticity on interface deformation and friction fluctuation are revealed by using a two-dimensional friction model considering viscoelasticity of materials.An in-situ microscopic test platform for rubber material texture friction is designed and developed.The effects of texture shape,material properties,compression and slip velocity on the friction and vibration characteristics of surface texture of rubber material are studied by using the test platform.It is found that the bionic hexagonal texture is the most stable.For PDMS samples with higher surface adhesion energy and lower modulus,different deformation characteristics of texture and contact interface appear with the increase of compression during friction.There are four vibration modes: bending vibration and stretch-springback vibration,overall stretching and springback vibration,and local interface stretching and springback vibration.The vibration amplitude and frequency of the texture are in a random state,and the random vibrations of multiple textures merge into a stationary vibration spectrum.For PDMS samples with small surface adhesion energy and high modulus,the textured contact interface is very stable and vibration free when the friction is in a large range of vertical compression.Under the same compression,the friction force,vibration amplitude and vibration frequency of a single texture increase with the increase of slip velocity.