Overhead Traveling Crane Metal Structure Allowable Stress Method Validation And Safety Assessment

The main objective of crane structure design is to make the structure satisfy all kinds of prospective functions in scheduled service period on the premise of economy, namely, possess enough reliability. With the development large scale, high speed and specialization for crane, general overhead traveling crane's status and function are paid much more attention, and metal structure is 60%～70% in total weight of a crane. In large harbor machinery such as a quayside container crane, metal structure is even 80%～90% in total weight of a crane. Result of stat, indicates that harbor crane accidents is usually the result of metal structure inactivation. Now some general overhead traveling cranes are used adjacent or exceeding twenty years in existing cranes, which leads to safety problem. Design plan and production technology of these old machines do not always accord with the need of current production because of temporal condition limit. There are important theory meaning and biggish engineering application when I study security evaluation technique about the structure of existing crane verification and safety assess.Because the steel bar rusts away, environment, climate, the load factor and so on change influence, the crane structure performance degenerates gradually along with the time, causing some elements of metal structures damaging, which will cause the failure of the overall structure of cranes. Therefore the structure of existing crane verification and safety assessment has aroused the engineers and technicians'widespread interest.The structure of existing general overhead traveling crane verification and safety assessment is a question which our crane engineering urgently awaits to be researched. To solve this problem in this paper, we use the allowable stress method to verify the structure of existing general overhead traveling crane from the design point of view——strength stiffness and stability. On this basis a Structure Safety Assessment Method for General Overhead Traveling Crane based on Bayesian Network is presented which in combination with the other appearance factors.A structure verification system of basing on allowable stress method for general overhead traveling crane was built based on software Visual C++ and Access database which has powerful storage capacity for all of the evaluation process above. We begin by analyzing the factors of general overhead traveling crane which influence the structure safety, this paper will analyze the causes of the structure crane accidents and the implicit factors of insecurity. By considering and analyzing strength factors, stiffness factors, stability factors and appearance factors, which have impact on the structure safety of general overhead traveling crane, it will be established a more practical evaluation index system of the structure safety, according to the internal causal relations. First, It introduces the Bayesian network when evaluating the structure safety of general overhead traveling crane. Then, it determines the Network node and its range. Finally, it establishes the topology of Bayesian network. Simultaneously, it determines the conditional probability distribution of node. and at the end, constructs the crane structure safety evaluation model of Bayesian network. After the simulation with Bayesian network analysis package, GeNIe Software, we will know that it is feasible to evaluate the structure safety of general overhead traveling crane by Bayesian network.