Design Of 250t Crawler Crane Boom

Crawler Crane is a lifting equipment which is applied to each field of national economy widely, with characteristic of small ground pressure, large grade ability, load traveling, etc. And with the help of other auxiliaries, multi-purpose function can be achieved, which leads to wide application in fields of electric construction, bridge construction, petrochemical industry, hydroelectric power and so on. With the growth of national economy, higher safety and quality are required. In the future, the development trend of the crane is safety design and control, extending more fields with large tonnage products as well as modularization, systemization and humanization.The core content of crawler crane's designing is overall design, including scheme selection, parameter determination, general layout, large structure strength and stability, overall stability, mechanism design and so on. The paper presents principle of overall layout and calculation method through research and analysis. Market availability should be fully considered in the overall design. Simple structure, easy installation, transportation and operation are also demanded, so are high commonality and high standard.Boom is one of the important load-bearing structures in crane working condition and its mechanical property influences safe use of the crane directly. In luffing plane, boom foot is connected to superstructure with shafts, which can be seen as fixed hinge support of the boom and the top pulled by rope as movable hinge support of the boom. Therefore, in luffing plane, the boom can be simplified to hinged-hinged simple beam. In slewing plane, the shafts installed to right and left of boom foot section can be simplified to fixed and movable hinge support separately. So the boom can be described as cantilever beam with fixed foot and moved top in slewing plane. Boom calculation method is determined and computation model is established through research and analysis in the thesis. The principle of load calculation and safety assessment is also determined in accordance with the specification. And then, loading mode and equivalent analysis of pulley unit are investigated using Finite Element Analysis (FEA) program in the paper. Analyses about the stress of each boom unit and stress assessment are performed combining with instances, and overall and local stability of the boom are analyzed as well. For the present boom designing, there is no explanation for global out-of-plane instability of the boom in the existing codes. The thesis provides analysis and discussion on the problem by examples.Crawler crane's lifting performance is determined by anti-overturning stability, structure strength and mechanical lifting capacity. Lifting capacity which meets the requirements of strength and stability is selected as the rated load in relevant I mode. Determination method of performance chart is obtained through experimental research and analysis. Close-up curve and suitable intersection indicate that strength and stability of the crane is fully utilized. The curve is drawn through computer program which is in favor of realizing the crane optimization. And the performance curve of 250t crawler crane is introduced as an example in the paper.