Problems in Fracture Mechanics

Fracture mechanics becomes a new subject focusing on studying the stress, strain, and crack extending pattern near the crack acme. In linear elastic fracture mechanics, the simplest method to calculate stress intensity factor of crack tip by the finite element method is the direct method. Bueckner proved that the elastic potential energy caused by crack developing only depends on strain energy in difference condition. This chapter introduces several energy methods to calculate the stress intensity factor. In order to calculate stress intensity factors by distributed crack model, Bazant put forward blunt crack zone model. For plane crack problems, the so-called J-integral method put forward by J. R. It should be noted that if singular isoparametric elements are adopted around the crack tip, the accuracy can still increase. The chapter finally presents the examples of stiffness derivative method.