Dynamic Simulation And Fatigue Analysis Of Elastic Damping Leaf Damper

Elastic damping leaf damper plays an important role in reducing the torsionalvibration of ship propulsion shafting. It can reduce torsional vibration of the shaft bychanging the natural frequency of the shaft. Due to the damping effect of the damper,elastic damping leaf damper can be effectively protect the engine crankshaft, camshafts,intermediate shafts and propeller shaft, the critical frequency of the shaft can beeliminated, Thus avoiding the diesel engine crankshaft work within the scope ofprohibited speed. Elastic damping spring shock absorber is usually mounted at the freeend of the engine crankshaft, It mainly consists of two parts consisting of the innermember and the outer member, spring pieces are set between the two groups. In thecourse of the operation of elastic damping spring shock absorber, main spring and reedgroup bending repeatly and bearing alternate load, Fatigue life of the elastic dampingleaf damper must be attention. Therefore, carrying the dynamics simulation and fatiguelife analysis of the elastic damping leaf damper, has very important theoretical andpractical value to improve the reliability of operational safety shock absorbers.This paper integrated application of multi-body dynamic simulation theory, thefatigue life analysis method and finite element numerical simulation technology, themechanical property of elastic damping leaf damper was studied, on this basis, thefatigue life of the leaf damper is calculated. The research work in this thesis can besummarized as follows:①First researches the propulsion shafting torsional vibration calculating,establishing the ship shafting vibration mathematical model and lumped parametermodel of a diesel engine crankshaft torsional vibration system. On this basis, usingHolzer table method to calculate the free vibration of shafting, using the transientdynamic method to compute the crankshaft system forced vibration respectively.②The modal analysis model of elastic damping leaf damper is established byANSYS. Using block Lanczos method to analyse the modal characteristics. Through thefinite element based modal analysis of damper, the natural frequency and normal modeof the elastic damping leaf damper are obtained③With the help of ANSYS/LS-DYNA, the solid models of elastic damping leafdamper are discretized, and then the contact finite element model can be created.Through the dynamic contact finite elements simulation, the stress contour of elastic damping leaf damper, dynamic contact force of between the spline shaft and the mainspring, and the max von Mises stress curve can be obtained.④Taking up the dynamic contact force of spline shaft and main spring duringrotation as the load spectrum，calculating the S-N curve of damper material based onGL standard, combining the stress strain result from static simulation of damper,fatigue life analysis can be conducted to elastic damping leaf damper byANSYS/FE-SAFE, then the logarithmic fatigue life and the fatigue safety factors ofelastic damping leaf damper can be obtained.