Failure Analysis And Improvement Of Diesel Engine Piston-pin

With the continuous development of the times,for the modern diesel engine,no matter its structure or its performance,it has a very great leap than in the past.The development of diesel engine is growing high speed,high strength,high power density,so it require the diesel engine parts have a longer life.Piston-pin is one of the most important parts of diesel engine.And it will bear the impact load during the working cycle.The main damage form is surface wear and fatigue.This article is aimed at making a series of research and analysis on the piston-pin which had cracks after working more than 9000 hours.We will analyze the problems from its structure design,and infer the largest possible reason of fatigue crack,and make the improvement plan.Based on the piston-pin in this essay,this paper mainly completed the following content: 1.The force of the piston-pin were be analyzed.According to the basic parameters of diesel engine and its working principle,we had calculated the diesel engine indicator diagrams.2.Uploading the original data of the indicator diagram,calculated the biggest downward pressure and the upward inertial force,and these will translated to subsequent calculations as necessary boundary.3.Based on the finite element method,establishes the finite element model of piston pin.To calculate its stress distribution of the original structure,and re-calculate the piston-pin with different boundary conditions.To study the effect of different structure size on the maximum stress.4.Import the FEM result to fatigue analysis software,analysis the safety factor of the original structure of the piston-pin and dangerous points.Analysis safety factor under different inner hole diameter,and put forward the improvement plan.