Influence Of Installation And Manufacturing Process Of New Type High-lock Bolt On Quality Of Interference Connection

Bolt connection is the main connection mode used in aircraft,and it is the main part of fatigue damage of aircraft structure.The fatigue life of the structure can be effectively improved by interference fit strengthening.High-lock bolts increase structural fatigue strength by interfering with the holes.Therefore,a large number of high-lock bolts are used for connection in the aerospace industry.However,it has been found the high-lock bolt interference connection causes protuberance in the connection plate,which can’t be applied to composite connection plate.Therefore,a new type high-lock bolt is designed in this paper.And the interference installation of new type high-lock bolt and its influencing factors are systematically studied systematically by theoretical analysis and finite element simulation.The best range of values for interference installation process parameters,reasonable manufacturing process and manufacturing deviations of affecting the quality of interference connection are obtained.Basing on the development status of the subject at home and abroad,following research has been done:(1)The new type high-lock bolt connection structure is designed,and in which the amount of interference is defined.Based on this structure,a interference installation model of new high lock bolt is established,and the force analysis of interference installation process is carried out.(2)The relationship between the installation interferences and the design interferences is studied by using the finite element simulation method,and the limit range of the design interferences is given.A new type of high-lock bolt interference installation two-dimensional axisymmetric finite element model is established.By comparing the elongation of the sleeve,the contact force between the sleeve and the hole,the uniformity of the actual interference amount after installation of different connecting plate materials,the influence law of the material of the connecting plate on the optimal design interference of the structure is obtained.(3)By finite element simulation,the best design interference of the structure is obtained,and the influence of lubrication state of the high-lock bolt rod,radius of the central hole of the top iron,number of layers and thickness of the connecting plate and installation mode on the installation quality is analyzed.(4)The influence of the rolling process on the fatigue strength of the structure under the corner of the high-lock bolt head was analyzed by the SWT equivalent stress method.Based on the finite element model of interference installation of new type high lock bolts,the influence of the deviation between high lock bolt and sleeve and between sleeve and hole on quality of interference connection of the structure is analyzed.