Strength Analysis Of Rack And Pinion Of Jack-up Platform

The largest number of Jack-up platforms have been being used in the offshore oil exploration and development. Rack and pinion lifting system is widely used on Jack-up platform. Lifting systems are to be imported at present. The strength of rack and pinion is one of the key technologies in our independent development of lifting system of Jack-up platform. The major works include the following:1,Rack and pinion meshing is a dynamic process. This paper uses ANSYS software to build a two-dimensional numerical model of rack and pinion, based on this model, the study on the stress variation of the tooth surface and tooth root of rack and pinion is carried on, when the platform is in the process of lifting operation under preload condition;2,According to the result of two dimensional dynamic analysis of rack and pinion, the critical locations in the process of rack and pinion meshing are confirmed, and a three dimensional part numerical model of rack and pinion is built, using this model the stresses of the tooth surface and tooth root are studied in detail. By analyzing the Von mises stresses and contact stresses on tooth surface for rack and pinion under different engagement positions, and comparing them with those calculated according to the formula, it is considered that the results based on FEM simulation could be used to evaluate the strength of rack and pinion;3,Based on the results of three dimension analysis, the optimizations are carried on rack and pinion from tooth width and tooth root fillet radius. Results showed that an appropriate increment on tooth width of rack could reduce the contact stress of rack and pinion, and increasing the tooth root fillet radius of rack and pinion could improve the bending strength of them;4,Considering the super high stresses of rack and pinion, some regions of them have entered into the plastic stage, so a three dimension elastic-plastic numercial model with hardened layer is built. Another model without hardened layer is also built for hardening treatment failure gears and the ones whose hardened layer have been worn out. For both models, the strength is analysed baseded on ANSYS,the study on the plastic zone and plastic deformation are also carried on, and compered them with the results of elastic contact analysis. This provides foundational mechanics datas for structure design of rack and pinion.