Effects Of Hygrothermal And High Temperature Environment On Properties Of T800 Carbon Fiber Composites

Composite materials are widely used in aerospace and various industries due to their many excellent properties.However,composite structures will suffer different degrees of damage during use and service,such as low-velocity impact damage.At the same time,composite materials will also be affected by the natural environment,leading to serious degradation of their performance.With the increasing variety and application of composite materials,it is necessary to study the change of properties of new domestic composite materials in typical service environment.This article was based on the National Defense Key Laboratory Open Fund Project.Discussed the influence of environments on the properties of undamaged T800 carbon fiber composite.Through low-velocity impact test and post-impact compression test,the damage characteristics of low-velocity impact and compression failure behavior were clarified.Finally,hygrothermal and high temperature aging tests were carried out to study the compression properties of damaged composites after impact by environmental factors.Mainly carry out the following aspects:Firstly,the undamaged T800 carbon fiber composites were subjected to hygrothermal aging test at 70?,high temperature aging test at 185? and corrosion aging test at 70?with mass fraction 3.5%NaCl solution.Through mass change curve,interface morphology,infrared spectrum and dynamic mechanical tests,the effects of environments on the aging behavior,interface morphology and mechanical properties of T800 carbon fiber composites were discussed.Secondly,the low-velocity impact test and CAI test were carried out for T800 carbon fiber composite.By the curve of impact energy and pit depth and c-scan damage morphology,the low-velocity damage characteristics of composite materials were analyzed,and the residual strength and compression failure behavior after low-velocity impact were discussed.Finally,the hygrothermal and high temperature aging tests of T800 carbon fiber composites with visual invisible low-velocity impact damage were carried out,explored the effects of environments on the damage morphology and damage area,and carried out environmental research on the compression characteristics of composite materials containing low-velocity impact damage after impact.At the same time,the macroscopic observation of the compression fracture morphology after impact was carried out to explore the influence of different damage aging states on compression failure behavior.