The Research Of Resistance To Low Energy Impact Properties Of Carbon Fiber Reinforced Plastic Under Hygrothermal Environment

Carbon fiber reinforced plasticresin(CFRP), which has an extensive application in aerospace industry, as a result of its excellent comprehensive performance. But the environmental condition and void have an effect on the mechanical properties of CFRP laminated plates, and the impact resistance and the other mechanical properties would suffer great changes after impact. So this study of the effect of void and impact on performance of CFRP laminated plates is provided with theory research significance and practical application value.Through the experimental investigation, the paper investigated the sorption and desorption properties of CFRP laminated plates with different porosity, there is also a comparison of morphology of voids, before and after sorption, effect of wet state, desorption and porosity on tensile strength, flexural strength, Brinell Hardness and degree of cure were carried out; after low enegy impact, the impact damage properties and the change of morphology of voids, the damage characteristic of tensile and bending samples, the effect of impact on tensile and bending properties of CFRP laminated plates were also discussed.The experimental study indicates that the majority voids in the CFRP laminated plates are roughly spherical and elongated oval, most of them were distributed in resins areas and interface between laminates. Metallographic observation and SEM analysis showed that microcracks coused by sorption were found near the voids and sorption also lead to debonding between the resins and fiber, the debonding can not be recovered after desorption, the sorption properties of CFRP laminated plates obey Fick's second diffusion law, the secondary water absorption would occur during absorption, the required time of the wet-saturated samples dehydrated to engineering dry condition is far lesser than absorption to saturation, the larger the porosity is, the faster the adsorption and desorption rate is, adsorption would remarkable reduce the tensile strength, flexural strength and Brinell Hardness, meanwhile, the degree of cure would be improved, after desorption, the tensile strength, flexural strength and Brinell Hardness would be improved, but the degree of cure would decrease, after the low-energy impact, by means of magnifier observation, ultrasonic C-scan and thermal deply technique, the damage and fracture of back was found to be more serious, there were more cracks near the voids, the fiber would be fracture when the impact enegy was higher, inflection point would be occur to the damaged area-impact enegy curve, the depth of the concave-impact enegy curve and the damaged area depth of the concave curve, the mechanics of the laminates drop more quickly and the impact resistance was worse when the porosity, impact energy is larger and absorption time is longer.