Research On Evaluation Method And Application Of Structural Health State Of Quayside Container Crane

Quayside container cranes are the main equipment of modern port handling operations,metal structure as its main load-bearing structural components,due to the harsh working environment,load conditions are complex,with the increase in service life,there will be damage failure problems,resulting in very serious safety risks.In order to ensure the safe and reliable operation of equipment,this paper addresses the complex system of shore-side container crane metal structure,load spectrum measurement,fatigue life assessment and comprehensive health state assessment and other research,the main contents are as follows.(1)Through on-site research and finite element analysis to determine the location of the test points,according to the crane operating conditions,operating environment characteristics of the combination of test conditions to carry out structural fatigue dynamic load testing;to reduce the noise interference in the test process,the test data to eliminate trend terms,remove burrs and filtering noise reduction and other pre-processing to extract the effective information in the test results;on the basis of the traditional rainflow counting method,by adjusting the data docking method to get an improved three-peak valley rainflow counting method,and statistical analysis of the pre-processed data to obtain the corresponding test points of the two-parameter stress spectrum,as the load basis for fatigue life assessment.(2)On the basis of the existing nominal stress method and damage tolerance fracture mechanics method,the traditional fatigue life estimation method is modified by introducing a double probability spectrum reflecting the working characteristics of container cranes to take into account the randomness of the lifting container weight and trolley operation amplitude.According to the non-destructive testing technology,the container crane detection results are divided into the case with cracks and the case without cracks,and the proposed modified calculation method is applied to estimate the fatigue remaining life of the crane under the two cases respectively,and the inspection period of the crack extension part is calculated accordingly to provide threshold conditions for the safety risk management and repairability assessment and decision making of metal structures.(3)To address the problem of ambiguity and randomness in the process of structural health assessment of container cranes,a comprehensive structural performance assessment method based on cloud model and extension analytic hierarchy process(EAHP)is proposed.Based on the cloud model theory,the determinacy of each evaluation index belonging to different evaluation levels is calculated,and its restricted distribution and transition potential between different grading criteria are quantitatively analyzed.The EAHP method is used to improve the judgment matrix of traditional point-value representation and generate indicator weights with higher credibility.Based on the determinacy and weights of each layer of indicators calculated layer by layer,the comprehensive determinacy of the assessment target is obtained,and the grade corresponding to the maximum of which is determined as the health grade of the whole structure to achieve the health state assessment of the in-service container crane structure under the coupling effect of multiple failure factors.