The ARMA Model Of Forecasting And Analysis For Fatigue Residual Life Of The Main Girder In Bridge Crane

The hoisting machinery is the indispensable production equipment in the modern production process, and it is playing vital role in the economic development. However the hoisting machinery actually is a kind of special equipment with most danger factors and biggest accident probability. A mass of accidents were caused by the hoisting machinery, and they have created the massive property damage and person hurt.In allusion to the main destruction form of metal structure of the hoisting machinery--fatigue crack,taking bridge crane's welded box girder as the object, based on the previous related experimental data and results ,apply the non linear regression theory to fit the fatigue crack extended distribution function of the bridge crane's welded box girder,and set up the the autoregressive moving average (ARMA) models of time series model to predict the fatigue crack length of the main bridge crane's welded box girder. Compile the software for special calculation of modeling time Series by VB and apply it in engineering examples. It shows that it is of high value in application. According to the fatigue fracture problem of the in-service bridge crane's welded box girder, base on the operating state of prsent in-service bridge crane's welded box girder, adopt time sequence forecast method of random process theory to forcast the future operating state of in-service bridge crane's welded box girder.Because of the scarcity of experimental data of fatigue failure, there is no an universal theory of fatige damage tile time.But, in this paper, the method of prediction of the ARMA Model with the non-linear fitting theory can solve the problem of scarcity of test data effectivly.And it can offer a new good prediction and evaluation method of fracture damage for the other special equipments'design. It shows that this forecasting theory is feasible, and the result of this method is comparatively accurate. In addition, prediction theory in this paper is widly used of engineering, like the prediction of fatigue breakage for metal component (most of the prediction of fatigue breakage for machine parts). So, this forecasting theory is also important meaning to design and application of other structures in engineering.