The Research Of Crankshaft Remanufacturing Evaluation Based On The Accoustic Emission/machine Vision Sensing

Remanufacturing engineering is an effective way to to build a recycling economy,realize energy saving and emission reduction and achieve sustainable development.Remanufacturing production object(or remanufacturing blank)is recycled scrap parts,residual life prediction is the key link to its re-manufacturability.Because of the complexity,randomness and individual differences scrap parts damage,making remanufacturing life assessment become a challenging problem.Failure forms of crankshaft mainly include fatigue and wear.Failure to wear caused by scratches,abrasions and other damage,you can go through brush,spray,laser cladding and other financial repair process.The destruction caused by fatigue failure,especially the emergence of fatigue crack failure of the crankshaft remanufacturing evaluation very difficult.This must be resolved is exactly how the crankshaft crack extension,extended to what extent can be remanufactured.Therefore,the study of the dynamic characteristics of the crankshaft extension fatigue crack has been the subject of attention of scholars at home and abroad.This dissertation to critical engine parts—crankshaft for investigation.Basing on the failure analysis,a finite element numerical simulation method combines with the bending fatigue tests and signal processing were taken to explore the ways for residual fatigue life prediction of crankshaft remanufacturing blank.The main conclusions of this dissertation are as follows:1.To establish the sound / light sensing information of the crankshaft remanufacturing blank fatigue life assessment system.Based on the acoustic emission sensor,the fatigue crack initiation information of the crankshaft transition is obtained.Based on the optical sensor of machine vision,the surface scale information of fatigue crack propagation is collected.2.Reveal the evolution law of multi sensor information in the process of fatigue crack initiation and propagation.Acoustic emission technology was first perceived fatigue crack initiation,for the crankshaft life assessment issued early warning information;with the crack growth,the machine vision signal to fatigue crack in response to the crankshaft fracture.The strong correlation between the geometric features of the crack propagation depth and the acoustic emission signal is explored.3.To make clear the propagation rules of crankshaft R angle parts of bending fatigue crack initiation: crack tip along the journal fillet surface expansion rate is faster,the crack along the shaft neck core expansion rate is slow;when the crack size more than shape than the threshold,the crack tip along the journal fillet surface expansion rate slowed,and crack along the shaft neck core expansion rate is in a rapid increase crack into a phase of rapid expansion.