Determination of Water Diffusion Coefficients and Dynamics in Adhesive/Carbon Fiber Reinforced Epoxy Resin Composite Joints

To determinate the water diffusion coefficients and dynamics in adhesive/carben fiber reinforced epoxy resin composite joints, energy dispersive X-ray spectroscopy analysis（EDX） is used to establish the content change of oxy- gen in the adhesive in adhesive/carbon fther reinforced epoxy resin composite joints. As water is made up of oxygen and hydrogen, the water diffusion coefficients and dynamics in adhesive/carben fiber reinforced epoxy resin composite joints can be obtained from the change in the content of oxygen in the adhesive during humidity aging, via EDX analy-sis. The authors have calculated the water diffusion coefficients and dynamics in the adhesive/carbon fiber reinforced epoxy resin composite joints with the aid of beth energy dispersive X-ray spectroscopy and elemental analysis. The de- termined results with EDX analysis are almost the same as those determined with elemental analysis and the results al- so show that the durability of the adhesive/carbon fther reinforced epoxy resin composite joints subjected to silane cou- pling agent treatment is better than those subjected to sand paper burnishing treatment and chemical oxidation treat- ment.

600 Mesh Silicon Carbide Corona Protection Varnish with EPOXY/OMMT Nano-composite Adhesive

A new corona protection varnish was prepared by using epoxy/montmorillonite nanocomposite and pure epoxy resin as adhesives respectively.The adhesive with different amounts of organic montmorillonite（OMMT） was mixed with 1200 mesh silicon carbide（Si C） by different weight ratios.The surface states of the varnishes with various adhesives were observed by powerful optical microscope.Some properties of the varnishes were analyzed during the enduring time under 5kV/cm DC,such as the relation of change in nonlinear coefficient,natural surface resistivity,and surface temperature variation.The results showed that the amounts of OMMT had little effect on the natural surface resistance of the varnish but had important influence on the nonlinear property of the varnish.When the range of the OMMT content was 2wt% to 6wt%,the nonlinear coefficient of all materials with epoxy/OMMT nano-composite adhesive was higher than that with pure epoxy resin adhesive.The surface temperature of the varnish with epoxy/OMMT nanocomposite adhesive was all lower than that with the pure epoxy resin adhesive under high electrical field strength.

Design and Research of a New Type of Ultrasonic Vibration De-Gluing Device

In this paper, a new type of ultrasonic vibration de-gluing device has been designed to remove the cured epoxy resin adhesive that overflowed from the aluminum alloy structural parts in the high-speed train carriages. At present, manual removal is used to remove the cured epoxy resin adhesive that overflows at the bonding site. This method has low removal efficiency and leads to poor surface quality of the parts. The new type of ultrasonic vibration de-gluing device can solve these problems. Modal analysis and harmonic response analysis are carried out on the ultrasonic vibration oscillator system in the ultrasonic vibration de-gluing device, and the reasonable structure parameters and resonance frequency of the ultrasonic vibration oscillator system are determined. Finally, the impedance test and de-gluing effect test are carried out on the prototype of the ultrasonic vibration de-gluing device to verify the feasibility and practicability of the new type of ultrasonic vibration de-gluing device. The results show that the ultrasonic vibration de-gluing device’s stable resonant operating frequency is 28,270 Hz, and the average error between the simulation and experimental results of the resonant operating frequency is less than 3%, which validates the simulation model.