Study On The Influence Of Bolt Preload On The Non-continuous Rotor Dynamics Of Aeroengine

Aeroengines occupy an important position in the military and civilian fields,and safety and reliability are one of the indicators that must be considered in their design and manufacturing.The vibration level of the whole machine will also directly affect the safety and life of the engine.As the core component of the aero engine,the dynamic characteristics of the engine rotor has always been a concern of researchers.Due to light weight,simple structure,flexible installation and disassembly,etc.,bolted discontinuous rotors are widely used in aero engines.The bolt pretension of the discontinuous rotor will inevitably deviate from the design conditions during installation and operation,which may cause excessive vibration and reduced safety.Therefore,it is meaningful to study the effect of bolt preload on the discontinuous rotor dynamics of aeroengines.Based on discontinuous rotor contact theory,thin-walled element modeling theory and finite element software,a discontinuous rotor model of bolted connection and a discontinuous casing model of bolted connection were established based on the discontinuous rotor of an actual aeroengine.After calculating the equivalent bending stiffness of the contact surface of the discontinuous rotor based on the contact theory,the spring unit with the same stiffness was used to replace the discontinuous rotor contact unit,and the continuou s rotor and discontinuous rotor under different bolt preload conditions were calculated and analyzed.The first four-order modal vibration model and the first four-order forward and reverse precession critical speed,and calculation and analysis of the unbalanced response of the bearing nodes of continuous rotor and discontinuous rotor at working speed By comparing and analyzing the dynamic response of different bolt preload conditions,and comparing with the dynamic response of continuous rotor,the influence rule of bolt preload on discontinuous rotor is obtained.Based on the finite element software and using three-dimensional solid element modeling,the static deformation and dynamic response of the discontinuous rotor under the uniform and uneven circumferential bolt preload force are calculated and analyzed;the bolt preload force size and The influence of the circumferential distribution of bolt preload on the discontinuous rotor.Considering the internal pressure of the engine,the deformation of the thin-walled casing due to the internal pressure of the engine is calculated and analyzed.The deformation of the discontinuous rotor of the engine is integrated.The possibility of dynamic and static collisions between the discontinuous casing and discontinuous rotor caused by the internal pressure of the engine is analyzed.