Research On The Effects Of Explosion Pressure Of 16V240ZJD Diesel's Cylinder On Fatigue Stength Of Transmission Shaft

With the development of heavy load and high speed trains, longitudinal tractive force and impact load acting on the diesel locomotives increase a lot. However, new problems such as the fatigue and fracture problems of key parts always appears, which brings great challenge to reliability and safety of these diesel locomotives. As fracture accidents happen frequently on the transmission shaft of 16V240ZJD locomotive diesel, the fatigue strength of the transmission shaft has been paid much attention to. In order to ensure the safty of transmission shaft, effective methods must be explored to enhance the shaft's fatigue strength.In this thesis, the tansmission shaft in 16V240ZJD diesel is taken as the study object. To offer simple method of security maintenance about the transmission shaft, the author uses CAE technique, i.e., the FEM and multi-body dynamics simulation technique, explore ways to enhance the transmission's fatigue strength by adjusting the cylinders'explosion pressures. In detail, the following steps are included: 1) Multi-body dynamics simulation technique are used to simulate the crankshaft's dynamics characteristic, analyze the fluctuation of rotational speed and torque; 2) Fluctuation of torque are reduced by means of adjusting the cylinder's explosion pressure; 3) The transmission shaft's load spectrum under different working conditions are derived from the output torque of crankshaft, and the Miner's cumulative damage rule is used to compute fatigue strength of transmission shaft; 4) Through comparing the fatigue safety factors among different working conditions, Methods to improve fatigue strength of the transmission shaft are found.The study shows that the crankshaft's fatigue strength enhanced most by last the explosion pressure of cylinder 1 to cylinder 8 and reduce the explosion pressure to level 3 of cylinder 9 to cylinder 16.