The Study, Based On Reliability Theory Of Fatigue Testing Of Metal Structures Of Bridge Cranes

Metal structure is the most important part of the overhead travelling crane, so, the aim of the paper is researching it's fatigue test and reliability theory. The paper combines test with mechanical fatigue statistics, probability fracture mechanics, engineering structure reliability theory and application theory, completes the following researches:1.The paper proves that the overhead travelling crane welding box beam logarithmic fatigue life meets normal distribution and fixed Miner linear accumulative damage law under the variable amplitude load, establishes the index function under the invariable amplitude load.2.The paper establishes the damage accumulation reliability analysis model for the existing overhead travelling crane welding box beam under the invariable amplitude and the variable amplitude loads.3.The paper firstly deduces the formula of C in paris under the variable amplitude load, and applies mechanical fatigue statistics, calculates C meets lognormal distribution.4. The paper establishes the probability fracture mechanics reliability analysis model for the existing overhead travelling crane welding box beam under the invariable amplitude and the variable amplitude loads.5. The paper applies the measuring fracture toughness of weld bead of welded box beam using stain method, and gets the fracture toughness through combining the test.