Reasearch On Security Evaluation Method Of Port Crane Metal Structure

Now, shipping is in the trend of larger and more professional, which makes harbor cranes more heavy-duty, high-speed and professional, 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. The age of metal structure is pivotal to that of a crane. A larger harbor crane is often costly and maintenance charge is larger. Along with the fast development of cargo thruput in ports, equipment collocate does not accord with the need of harbor developing. Now some harbor portal cranes are used adjacent or exceeding twenty years in some small-and-medium-size ports, 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 metal structure of harbor cranes. Following study work is done based on experiment research of structural metallic materials, fault statistical analysis and evaluation technique about the metal structure in existence.1. Q345 steel is used widely in metal structure of harbor machinery at present. The material constants and fracture toughness are confirmed through experiments in the paper. It has filled the blank of crack growth parameters. It has established a base for crack research of structural member used Q345 steel in harbor machineries and the scientific gist has been provided for supervisor control and evaluation of Q345 steel cracks.2. Aiming at problems about security evaluation of metal structure of old port portal crane, fault tree analysis charts and a fault analysis model of Bayes net based on Fault tree of several portal cranes was been established based on in-depth analysis. The method that a fault tree is changed into a Bayes net has been studied in order to accounting for the problem that fault tree of a polymorphic system is complex and calculating amount is larger. Generic rules of fault types and occuring position of metal structure of port portal cranes in common use have been gotten through fault tree and Bayes net analysis. It was validated by method of finite element. A reference is supplied for confirming the detection positions of metal structure faults of a crane.3. A security evaluation system frame has been established that is multilayer, multivariate and multi-index. Aiming at the phenomena that well-balanced members and fault members coexisted, it was put forward that well-balanced members and fault members were evaluated respectively by well-balanced indexes and fault indexes. Confirming methods and limiting values were studied and summarized about well-balanced indexes and fault indexes. Zero dimension formulaes were established after security evaluation index characteristic of metal structure had been analyzed. A base was established that confirming the evaluation value of each layer.4. Laminary confirming weighting was put forward after weighting characteristic of security evaluation system and evaluation object characteristic of each evaluation layer were analyzed. In order to stand out fault indexes affecting the evaluation result, I have studied variable weight method based on punishing type variable weight. In order to use the reference of experts, I have studied a confirming weighting method to confirm weighting of subsystems based on mending single rule AHP method and weighting self-study of Bayes net.5. Using a mix synthesizing method and combining fault characteristicof crane metal structure, synthesizing principle and established synthesizing formula of each evaluation layer were put forward in order to settle a problem that evaluation value of few indexes were neutralized. Partly the function of softer of security evaluation of crane metal structure was developed and realized. It was used to evaluate security of a portal crane metal structure and validated applied value about key technology of evaluation security of crane metal structure.