Tire Crane Safe Operation Of The Metal Structure (boom)

Port enterprises mainly load and unload cargo with large port machines, lots of which are extremely old, and even on the edge of expiry. So accidents usually happen, which badly disturb the regular production and need strict regulation. This paper takes the arm structure of the two different types of truck crane in my company (namely Tianjin Harbor Second Stevedoring Co. Lid) as research object. In the paper, we systematically discuss and evaluate the stability of the structure in combination of the actual testing data of QLY25 and UC25.The safety of structure includes static strength, dynamic strength, fatigue and stability; in this paper we mainly discuss the stability of the boom. According to former records, accidents usually happen to both the boom structures of QLY25 and UC25, so we can make the conclusion that these accidents of boom breaking are caused by the invalidation of structure stability. On the basis of structure stability we analyze the reason of the boom breaking in comparison of the actual testing results in order to adopt suitable measure.We begin the paper with the stability of the boom, discussing the stability of the chord rod and the ventral rod. In the paper we also give the general graph, which is jointed by the line formula, the yield limit and the Euler's formula.In the paper we also introduce the parabola formula that is used when it goes out of the limit of proportionality and the applied calculation of the decreasing coefficientφ.Compared with the critical stress we get from the parabola formula, the stress of the actual testing is far lower than it, but why the failure of the stable equilibrium still happens? We turn to the stability of the whole boom in the Chapter 4. There we mainly discuss two problems.One is how to calculate the critical stress when the boom is with the cone in the two ends and the same section in the middle.The other is the influence of the cut deformation on the critical stress of the crib.From the results of the general stability analysis we know: because of the consideration of the cut deformation, the critical stress of different length all...