Analysis Of Biaxial Fatigue Behavior Based On Finite Element Method

Emergence and development of bridge structures fatigue design methods are introduced based on constitutive relationships of materials under biaxial stress states. And the differences of these design methods are also disscussed. Theory and method of fatigue design used in China code,BS5400 and Eurocode 3 are introduced and compared. It is development tendency that shear stress fatigue is considered in the design code of bridge structure faitgue.The main research and analysis contents in this thesis are as follows:1. The uniaxial fatigue criteria. and multi-axial fatigue criteria are introducted. The multi-axial fatigue damage accumulation model and uniaxial fatigue damage accumulation model is also discussed.2. Classical fatigue design theories and conventional fatigue design methods for bridge structures are discussed.3. Ideas and methods for fatigue design of bridge in some countries are analysed, and the difference in specifications are compared.4. The finite element method for multiaxial stress-strain analysis and for material elastic-plastic analysis are discussed5. The mechanical behavior of cross-like test specimen is analysed by finite element method. The differences between biaxial and uniaxial fatigue by common fatigue damage criterions are evaluated. The fatigue behavior of the test specimen in local plasticity status is also calculated using elastic-plastic finite element method.