Study Of Torsional Vibration Characteristic Of Dual Mass Flywheel System

Torsional vibration of power train system is one of the main factors which affects working reliability and life-span of engine, as well as ride comfort. Like other elastic system, it causes torsional vibration under actuating actions such as piston pressure, weight of moving parts, reciprocating inertia force, resistance moment during driving. When the frequences of actuating torque equals or is close to the frequences of natural characteristic frequences, it can cause resonance, endanger vehicle life span, ride comfort, passing ability and so on. With engine development turning to higher speed, lighter size and more powerful direction nowadays, the torsional vibration becomes more serious, on the other hand, the requirements becomes to more strict, as a result, it has great significance of studying torsional vibration of power train system.This dissertation studies torsional vibration of power train system of a type of SUV automobile matching VM disel and Dual Mass Flywheel(DMF), mainly includes 4 aspects: (1) Torsional vibration system model was built; (2) The natural characteristic was calculated, analysis of actuating action and response of forced vibration; (3) A software solving analysis of torsional vibration of power train system was designed and developed; (4) Simulating calculation and test verification.Firstly, the dissertation introduces the development of torsional vibration analysis of power train system at home and abroad, especially about model building method, calculating method, as well as DMF damper. And then the study content and its significance were illustrated.Secondly, theory of equivalent molel building of torsional vibration system was introduced, by means of 3D design software and FEA method, based on equivalent model building principle and structure of VM engine, the equivalent model of power train system under different grade gearshift was built.Thirdly, on the basis of torsional vibration theory and analysis method, natural characteristic of power train system of the automobile matching VM disel and DMF was calculated and analyzed, and harmonic analysis of the engine was done. In light of dynamic magnification factor method, the response of the system with DMF under engine compeling was calculated. Fourthly, torsional vibration theory and analysis method was integrated to design a torsional vibration analysis software of power train system, which can realize efficient calculation, analysis of natural characteristic and engine actuation & response of forced vibration.Finally, simulation of dynamic analysis was done by the software ADAMS, which was compared with the theoretical calculation, both results agreed with very well. Therefore, from the study of this dissertation, we can fully confirm that DMF powertrain transmission system possessses better damping effect than other powertrain transmission system.