Study On Interface Properties Of Carbon Fibers Reinforced Composites By Ultrasonic Surface Treatment

CFRP(Carbon Fiber Reinforcement Plastic) is one of the most advanced composites, it has been widely used in the field of spaceflight. But there are many disadvantage on the interface of composites, which effect in the mechanics capability directly, especially the ILLS(Interlaminar shearing stress), which restricts high-powered using of carbon fibers. It can enhance the correlative capability of composite effectively by mechanical and cavitation effects of power ultrasonic. We use power ultrasonic treating the interface of CFRP to enhance its ILLS.By learning the basic theory of composites` interface and ultrasonic effect factor, we concluded the main point of ultrasonic surface treatment for composites: ultrasonic degassing, cavitation corrosion, ultrasonic separating and so on. It provides us theoretical reference for vibratory system and experiment.We manufactured an ultrasonic vibrancy system, whose vibratory speed rate reached 25. We made a optimal round transition at the unequal section joint of stepped ultrasonic transformer to avoid its break; at the end of the solid horn, we made baffle to avoid carbon fiber fall off while working. We analyzed and calculated the variation law of the node position due to the variation of resonance frequency, and ascertained the thickness and position of fixed node. The design frequency of ultrasonic vibrancy system is 21 KHz, the measured frequency is 20.76 KHz, the distinction is 1.1%, which achieved the design request well.Study on the law of ILSS and variation coefficient on swing of ultrasonic, the twist speed of carbon fiber, and environment temperature, show that: when the ultrasonic swing during 30-40μm, the ILLS of CFRP enhanced 10%, variation coefficient reduced 50%, and the stability of composites elevated; the twist speed of carbon fiber increased from 5m/min to 10m/min, which increased work efficiency; that ultrasonic effect on composites at the temperature of 20℃, equivalent to originally effect at the temperature of 50℃, which reduced the working energy consume.