Effect Of Temperature And Humidity On Interlaminar Aging Characteristics Of Vehicle CFRP Plates

In recent years,with the gradual improvement of automotive lightweighting requirements,lightweight composite materials such as CFRP have been applied to actual manufacturing by more and more automobile manufacturers.The most widely used is planar orthogonally laminated carbon fiber.The mechanical properties in the plane are generally stable and not easy to break,but the lack of fiber reinforcement between layers is the weakest direction.Moreover,the automobile is often used in an aging environment such as severe temperature and humidity,and the carbon fiber interlayer structure on the automobile is more susceptible to aging damage in this environment.Therefore,this paper mainly studies the influence of the aging environment of automobile on the Interlayer structure of carbon fiber,finds the variation law of the structure of under different aging conditions,and proposes a method for predicting the Interlayer structure performance of carbon fiber after aging.It provides a theoretical basis for the wider application of carbon fiber composites in automobiles.The details are as follows:(1)In combination with the actual automotive operating environment,this paper designs high temperature(80°C),low temperature(-40°C),high and low temperature cycle(-40°C~80°C)artificial temperature aging environment,and the corresponding carbon fiber interlayer tensile,Shear and bending aging performance test experiments,the carbon fiber interlayer performance after different temperature aging time was tested by corresponding experiments,and the curve of carbon fiber interlayer performance change with aging time was established,which was combined with macroscopic observation and chemical property test.The method reveals the aging mechanism of interlayer performance and compares the degree of influence of different temperature aging environments.(2)Based on the study of temperature aging,this paper studies the wet-heat coupling aging of carbon fiber interlayer structure.Combined with the actual automotive operating environment,this paper designs high temperature and high humidity(80°C/95%RH)and humidity-temperature cycle(-40°C/30%RH 80°C/95%RH)Artificial aging environment,and the carbon fiber interlayer performance after different wet-heat aging time was tested by the corresponding carbon fiber interlayer performance test to establish the carbon fiber interlayer performance variation curve with wet-heat aging time.and reveals the aging mechanism of interlayer performance through the combination of macroscopic cross-section observation and chemical property test.The effect of different aging environments on the performance of carbon fiber interlayers was compared horizontally.(3)Because the high temperature aging environment has a great influence on the interlayers performance of carbon fiber,this paper takes high temperature aging as an example to establish a carbon fiber interlayer performance prediction model with aging time.In this paper,the curve of carbon fiber interlayer performance change under the high temperature aging environment is introduced into the secondary stress criterion of the cohesive model,and the secondary stress criterion response surface with high temperature aging time is established.The high temperature response surface is established.And calculating the cohesive model parameters by the aging degradation factor after different high temperature aging time,and brings the above aging parameters back to the cohesive model to complete the carbon fiber interlayer performance prediction model after high temperature aging.Through the above research methods,this paper clarifies the variation law of carbon fiber interlayer performance and its aging mechanism under different environmental aging conditions,and effectively establishes a prediction model that can analyze and calculate the carbon fiber interlayer performance after high temperature aging.