Applied Mechanics and Materials Vols. 10-12

Abstract: In order to ensure diesel engine operating reliably, need to forecast the performance parameters of diesel engine. Grey system theory, a method to research poor information and uncertain system, was approached to sequential turbocharged diesel engine. Grey forecast model of boost pressure of sequential turbocharged diesel engine was established. The precision of the forecast model was inspected by grey relation analysis, it is proved that the model has a good precision and is suitable to forecasting boost pressure. The relatively error of the forecast result is 2.5%. And it establishes the base for forecasting control and failure prediction of diesel engine sequential turbocharging system.

Abstract: Reviewed the achievements and advances in the vibratory metal machining, analyzed the features and mechanics in microstructure with SEM. The dynamic stress intensity factor is derived on the basis of fracture mechanics and stress-wave theory with the Griffith- II type sliding-open crack.. Comparison between the vibratory machining and the conventional machining has been made with brass on lathe CW6150B, with computer controlled piezoelectric ceramic micro-drive system and cutting forces and surface texture of the specimen were observed. The dynamic stress intensity factor was discussed and it was found that the value of dynamic stress intensity factor may be high with response to the Heaviside impulsive loading, indicating the reason why vibratory machining has better comprehensive results than the conventional one does.