Study On Fatigue Behavior Of Carbon Fiber Reinforced Composites Under High And Low Cycle Lodas

Carbon fiber reinforced composite material is one of the most advanced composite materials,its development and application has always been one of the important contents of contemporary high technology,and is widely used in aerospace and other projects.Due to the particularity of the material,it has a good resistance to fatigue,at the same time due to its light quality characteristics,so more and more aircraft engine blades use composite materials to replace the alloy,so it is very necessary to study the fatigue properties of the composite material.At present,many of literatures pay much attention on studying constant load fatigue of the material.But when the aircraft works in actual situation,the fatigue load it supports is mutative even random.So it is very necessary to start the study of fluctuating fatigue.In this paper,the theoretical and experimental studies on the high and low cycle fatigue are carried out,including the residual stress of composite fatigue and the prediction formula of life.The specific methods are as follows.1.Introduce the basic fatigue theory,give the equal life curve.At the same time,we use the single-level residual strength model to derive the two-level or even multi-level residual strength model formula,and give the li fe prediction formula.Two methods of deriving damage of materials are proposed which based on the damage criterion2.Start the static tensile test and the constant fatigu e test and find the S-N curve.Start the residual strength test and find the residual strength curve.Analysis the broken section of the material.3.Start the high and low cycle fatigue test and find the regular pattern of the material under different stress ratios and different frequency.Start the life test about a perforated plate and use the USDFLD subroutine and ABAQUS to verify the applicability of the life prediction method.