The Metal Structure Design Verification And Safety Assessment For General Overhead Traveling Crane

For a long time the method of structural design of General Overhead traveling crane is the allowable stress method.Allowable stress method using a single safety factor to measure the metal structure to withstand the loads,material uncertainties,and this method has drawbacks which both theoretical and practical structural design calculations.Metal structure is a "skeleton" which is the main load-carrying parts for Lifting crane.In order to achieve the function of various requirements during the life of the structure,studying a suitable design for the structure is essential. "GB/T3811-2008 Design Rules for Cranes"[5] which issued newly in china introduced the limit state method. The limit state method which based on probability theory and statistics is using partial factor instead of safety factor, it gives full consideration to the load and material uncertainty. From Allowable stress design to limit state is making the design value method transition to the probability method of the structure.According to the report of the State General Administration of Quality Supervision, the accident caused by the crane structure is constant and showed upward trend year by year. These incidents caused a huge loss of the state's infrastructure and personnel.The designers are facing a major issue that how to reduce the occurrence of such incidents effectively. Domestic and international experts found that if makes safety assessment for the structure of scientific and effective evaluation, to identify risk factors and potential safety problems and take measures timely can effectively reduce accidents.In the early stage of safety evaluation of the domestic crane metal structure, mainly used the fault type and effect analysis, fault tree analysis and other traditional methods of AHP.These methods are simple in statistically, but the analysis of the accident is too simple. With the advances in biology and computer technology, Artificial Neural Networks development has been rapid. This is the first application of the BP neural network to the general overhead traveling crane metal structure of the safety evaluation in the papers. Building the safety assessment model based on the BP network theory for the structure and combining with AHP to establish the common security Evaluation System for the Metal Structure, Using the samples collected in BP network training which based on BP network's self-organization, self-learning and the characteristics of a high degree of parallelism. Using Matlab7.0 software development the corresponding program, the security evaluation results and expected results of error is small through authentication the BP network. The convergence and the error precision of better high of the BP network, so this network is fully meet the needs of crane structure safety evaluation.Using visual C + +6.0 as development platform to develop" The general overhead traveling crane metal structure design verification system based on the limit state method"in thesis, through verification by an engineering example, the system of verification results is consistent with the actual results, and the limit State method results larger than the allowable stress method, so the design makes the structure more Margin and more economical.