Strength Analysis And Dynamics Of Rack And Pinion For Self-elevating Offshore Platforms

Gear and rack lifting system is one of the key devices of the jack-up platform,the bearing capacity and dynamic characteristics are the key factors influencing the safe and stable operation of jack-up platform.Based on the latest research results of the jack-up platform of foreign,the lifting system of jack-up platform is designed in this paper;By means of finite element analysis and dynamic analysis,the strength analysis and dynamic analysis of the gear and rack device of the lifting system are carried out respectively;The effects of different cracks on the strength of rack and pinion are analyzed.The main contents of this paper are as follows:First of all,the gear and rack lifting device is designed from the aspect of structure,and the three-dimensional model of the lifting device is established by using the three-dimensional modeling software Pro/E;Through the analysis of the force,the feasibility of the lifting device is proved;The modeling method of the large modulus gear is written,and the 3D modeling of all the components of the lifting device is completed and assembled.Secondly,the finite element analysis software is used to analyze the gear and rack mechanism of the lifting system.The stress distribution of the key areas of gear and rack is analyzed;The contact stress and bending stress of gear and rack under the condition of pressure angle and modulus change is analyzed respectively.Thirdly,the method and steps of gear dynamic analysis based on ADAMS are studied.The dynamic analysis of the lifting device is carried out by using ADAMS software,and the curves of the meshing force of the gear and rack under different load conditions are obtained.The meshing force of the gear and rack under the condition that the gear is not completely broken and the tooth is completely broken is analyzed respectively.The dynamic analysis of the rotary gears is carried out.As a result,the meshing force curves of the pinion and the ring gear are obtained under different load conditions and different speed conditions.Finally,based on the previous finite element analysis,the gear tooth root crack model with different length,depth and width is established established respectively.The influence of the length,depth and width of the crack on the maximum concentrated stress,contact stress and bending stress of the rack and pinion is studied.