Analysis And Research Of Stress Intensity Factor For Cylinder Surface Elliptical Crack By Means Of Finite Element Method

In light of the theory of the fracture mechanics, the stress intensity factorof cylinder surface elliptical crack has been analysed and researched bymeans of finite element method:Domestic and foreign present state of making researches on the stressintensity factor for surface crack is discussed, the merits and drawbacks ofvarious methods in researching into stress intensity factor of surface crack arecompared .It can be seen the advantages of the finite element method are thatthe layout of elements and nodes is flexible and it has no special restrict to theshape and position of crack.General and basic problems are discussed when problems are analysedby using ANSYS parametric design language APDL. The application of bothANSYS command stream and language of APDL in numerical simulation ofthe fracture mechanics is researched.The study of the dimensions of singularity element affecting results hasbeen done. The best dimensions scope of singularity element are selected soas to make versatility and accuracy of the method very high.The research indicates that the biggest value of stress intensity factor ofcrack tip in cylinder surface elliptical crack presents in the deepest point orthe surface point, it also presents in some center points (the radian value ofseparation angel from line which ties center point to the middle point ofellipse to semi-minor axis is at 1.066-1.327).Through analysis, change regularity of stress intensity factor of thedeepest and surface point in the cylinder surface elliptical crack have beenobtained and the variety curve of stress intensity factor of advancing edge in cylinder surface elliptical crack have been described.The results obtained in this paper are consistent well with theexperimental results. It provides the important reference value towards thefracture mechanics applying in engineering practice.