Research On Hotspot Stress Monitoring And Fatigue Damage Of Portal Crane In Port

Crane,a kind of special equipment,with the rapid economic development,is used in the fields of metallurgy engineering,mining industry,railway engineering,transportation,hydro-power,shipbuilding industry in recent years.However,due to the large weight,strong operational continuity,mobility,poor environment and other factors,the crane become prone to a variety of accidents,resulting in casualties and property damage.In this paper,the research of monitoring portal cranes hot spot stress and predicting fatigue damages is carried out.The accurate selection of the stress monitoring point is the key factor to effectively carry out the fatigue damage.With the analysis of the weld fracture failure and the factors affecting the crack initiation of the gantry crane,this paper puts forward the way of stress monitoring of the high-risk fractured weld zone of the portal crane.The multi-scale starting point evaluation matrix is established,which are the arrangements of locating the sensor in the stress monitoring of the portal crane,and it has important application value.This article is mainly from the following aspects:(1)Through the investigating and reading a large number of literature searches,the accident cases of the portal crane are counted and analyzed,and the typical structure and working characteristics of the portal crane are described.The present situation of the stress monitoring and fatigue damage research of the portal crane is introduced.The problems facing to the development of gantry crane health monitoring are mentioned.(2)The basic principle,structure and classification of fiber grating sensors and resistive strain gauges are described.The advantages and disadvantages,development trends and application prospects of the two kinds of sensors are introduced.Combined with the characteristics of complex structure of hoisting equipment and changing environment,the reliability of lifting equipment stress monitoring in sensing technology is discussed.The basic theory and method of fatigue damage are introduced and the fatigue analysis is introduced.(3)This paper introduces the basic process and method of fuzzy identification method to determine the high risk fractures,and uses this method to determine the evaluation vectorand weight of each factor and find the high risk fractures of the crane.(4)The paper systematically expounded the initiation factors of fatigue crack in welds,introduced the principle of stress concentration by using magnetic memory method and the basic principle of fracture resistance of indentation method,and put forward the standard and algorithm of stress concentration degree.Fuzzy identification method constructs the evaluation vector and the weight vector of each influencing factor to create the method to determine the multi-scale crack initiation point of the crane.(5)According to the fuzzy recognition and multi-scale initiation point determination method,the key points are found out,and the probability of initiation of these points is calculated.Stress monitoring of the normal working conditions of the lifting equipment is carried out,monitoring data and fatigue damage budget are collected.Compared with the actual monitoring situation,the reliability of the proposed method is verified.(6)The method of determining the location of portal crane and the development of the stress monitoring technology are forecast.The structure of the health and safety system of the lifting equipment based on the sensor monitoring technology are conceived.The main points of this paper are summarized and the shortcomings of the paper are discussed.And the prospect of the next research work is looked ahead.