Interfacial Characteristics And Variable Stiffness Design Of Carbon Fiber-Silicone Rubber Composites

As an advanced technology in the field of robotics research,soft robots have always been the focus of researchers.Among them,carbon fiber silicone rubber composite materials as a new type of intelligent materials for large deformation and small bending stiffness have important application prospects.Based on the research of carbon fiber silicone rubber composite materials,the experimental research and simulation analysis of the interface bonding strength of carbon fiber silicone rubber composites were carried out in this paper,and the fiber curve configuration were designed to make the composite material exhibits variable stiffness characteristics.Firstly,according to the interface failure mechanism of fiber-reinforced rubber materials,the combination of pretreatment,liquid oxidation method and chemical coating method were used to treat the surface of carbon fiber,and the scanning interface electron microscope and mechanical test were used to measure the interfacial adhesion characteristics at the contrast between the original one and the renovated one.The results show that the pretreatment method effectively cleans the impurities on the surface of the carbon fiber,the liquid oxidation treatment obviously etches the surface of the carbon fiber,and increases the contact area of the fiber and the matrix material.After 6 hours of treatment,the interface adhesion increased by about 40%.On this basis,the coating method,silicone coupling agent(KH550),was used to study the influence of time,temperature and concentration factors on the interface adhesion.The results show that the above factors can change the adhesion of the interface,and the effect of the temperature factor is more obvious.Secondly,the finite element analysis software ABAQUS was used to simulate and analysis the mechanical properties of the interface.In order to accurately describe the mechanical properties of the interface during the separation between fiber and matrix,the Cohesive cohesion model was introduced,and the bilinear tensile separation criterion was selected.As the constitutive model of the interface element,the results of the simulation calculation describe the process of interface failure intuitively during the process of pulling out the matrix material.At the same time,the stress data map of the interface element and the damage index along the interface path(SDEG)shows the mechanical characteristics of the interface effectively during the stress process.Finally,the mechanical effect of the fiber placement in the composite on the variable stiffness mechanism of the composite was studied.the discrete modeling model in the finite element analysis software was used to establish a discrete grid model in this paper.though MATLAB,the overall curve trajectory and grid angle change under two angles of <0°|45°> and <0°|60°> were calculated.The results show that the curved shape configuration of the fiber effectively reduces the stress concentration of the composite material and improves the bearing capacity of the material,and the higher the fiber curvature,the more obvious the effect of reducing stress concentration.It provides a certain theoretical basis for the application of soft robot materials.