Based On Finite Element Analysis Of Diesel Engine Crankshaft Remanufacturing Research

The traditional repair techniques have been unable to meet the requirements of thecrankshaft repair，as the crankshaft failure in the form of complex and the increasing qualityrequirements after the crankshaft has been repaired. In recent years, as the core of the laserremanufacturing technology—laser cladding technology has rapidly developed into a newcrankshaft remanufacturing repair technology.The main content of this paper is about that theremanufacturing problem of the marine diesel engine waste crankshaft.1. From the crankshaft wear, erosion, cracks and bending and torsion deformation andfracture in four areas, detailed analysis of the reasons for the failure of marine diesel enginecrankshaft, draw the following three points:(1) Checking static strength safety factor, assesses the reliability of the crankshaftstiffness, hardness and load bearing capacity. Checking the fatigue strength safety factor,assesses the fatigue life before and after remanufacturing of marine diesel engine crankshaft.(2) According to the law of fatigue crack growth and Paris formula, predicts fatiguecrack growth life of the crankshaft.(3) Through a simple analysis of the crankshaft material properties, using traditionalfatigue life prediction method, damage mechanics and miner fatigue damage accumulationcriterion to determine the prediction method of the remaining fatigue life of the crankshaft,that is, first predicts the fatigue life of the crankshaft under maximum load, then minus theequivalent life under maximum load, the difference between the two is the remaining fatiguelife of the crankshaft.2. Using1/4point displacement method and the J-integral method to calculate the stressintensity factor of the crack at crankshaft fillet, judges it’s degree of fracture failure, whileapplies the15-node three-dimensional1/4singular element and20-node three-dimensionalunit, analyses the stress field of the crack at crankshaft fillet and finds the stress intensityfactor.3. Against the problem of the crankshaft remanufacturing, the paper studies the principleand main characteristics of laser cladding, provides a theoretical basis for the matching ofcladding material and the matrix material of crankshaft; chooses nickel, cobalt and iron basethree kinds of self-fluxing alloy powder as cladding materials; determines the Repair processto be the synchronized laser cladding. The research on the pool State provides a theoretical basis for the thermal analysis below, and provides a solution for the control of cracks in thecladding layer.4. According to the finite element theory of temperature field and the basis of thermalanalysis of ANSYS, get the distribution of the temperature field, displacement, and the stressfield inside the crankshaft after60seconds through the finite element thermal stress analysisof the remanufactured crankshaft and the temperature distribution data of three kinds ofcladding material’s droplet at100microseconds. According to the stress state theory of thecladding layer, analyzed the residual stress fields of the three cladding layer, obtains that thecombination of Fe-based self-fluxing alloy powder Fe55and the crankshaft substrate is betterand it’s cladding effect is well by comparison.