Semi-analytical Finite Element Method For Quasi-brittle Material Fracture Analysis Based On Cohesive Force Model

Aiming at the plane elastic-plastic fracture mechanics, a kind of new combination ofanalytical and finite element methods is extended to a series of problems in the planeelastic-plastic fracture mechanics in this contents. Employed the Hamiltonian system theoriesof elastic mechanics, several hyper-elements are formulated to describe the crack tip fieldsaccurately with simplified fracture models for reinforced concrete structures or composites.Implemented the hyper-elements into ordinate finite element system, a kind of semi-analyticalfinite element method is then constructed to analyze the elastic-plastic fracture problems ofreinforced conctete structures considering the bridge tracsaction effect.The thesis deals with the fiber reinforced materials such as reinforced concrete,composites etc. The model of bridge transaction is introduced to the hyper-elements based oncohesive force model. The main work of the thesis is as following:1. Combined with bridging transactions model and Dugdale model, an analyticalelement is built for mode I crack model. Using the semi-analytical finite element method, wecalculate plastics zone and opening displacement for some typical problems with bridgingtractions and cohesive force models.2. Combined with bridging transactions model and Dugdale model, an analyticalelement is built for modeâ…¡crack model. Using the semi-analytical finite element method, wecalculate plastics zone and opening displacement for some typical problems with bridgingtractions and cohesive force models.3. an analytical element is built for modeâ… +â…¡crack model, solution K_â… , K_â…¡and crackangle in situation of complex crack, and gains stress intensity factor and crack angle insituation of complex crack which is concerned in engineering.Numerical results for the above typical problems show that semi-analytical finiteelement method has good precision.