Processing Deformation Control And Process Optimization Of Cast Iron Pistons For Marine Diesel Engines

Piston is the "heart" of marine diesel engine,which determines the power,reliability and economy of diesel engine,and is one of the most critical components of diesel engine.Piston transfers the power of diesel engine through high-speed reciprocating motion.Failure to meet the processing accuracy standards usually results in destructive failure such as pin hole cracking,side wear and cylindrical damage,which affects the service life of diesel engines.Because of its complex structure,thin wall thickness and poor radial rigidity,it is easy to produce deformation in the production process,and it is difficult to guarantee the processing quality.Therefore,it is very important to study the processing technology of marine cast iron piston and optimize the processing parameters to reduce its deformation and ensure the processing efficiency.In this paper,the processing deformation of cast iron piston in key process was studied.The actual processing process was simulated by finite element method,and the effects of clamping and cutting on the processing deformation were discussed.On this basis,it was assisted by relevant experiments to verify.Finally,the optimal combination of cutting parameters was found by using the mathematical regression modeling ability of MATLAB and the optimization ability of intelligent algorithm.The main contents are as follows:(1)Based on ABAQUS software,the clamping simulation model of the key process of piston was established.The effect of different clamping loads on the deformation of piston was studied,and the corresponding clamping experiments were carried out to verify the simulation results.At the same time,the optimization scheme was formulated to solve the problem of large clamping deformation in rough turning outer circle process.(2)The simulation model of piston cutting was built by Deform-3D software.The influence of cutting speed,feed and cutting depth on cutting force and cutting temperature was studied,and the response surface prediction model of cutting force and cutting temperature was established.Finally,the influence of cutting parameters on cutting force and cutting temperature was visually analyzed by response surface graph.(3)On the basis of obtaining the cutting load and cutting temperature of the piston,the machining deformation of the integral piston structure was simulated by the element life-and-death method in ABAQUS software.And the influence of cutting parameters on piston deformation was studied by orthogonal experiment.According to the simulation results,a residual stress measurement experiment was designed to verify the reliability of the finite element calculation results.(4)The prediction model of cutting parameters and deformation in the process of piston key processes was established by using the neural network algorithm.Taking the model as objective function,the optimization parameters of the key process of piston can be calculated through the advantages of non-linear programming optimization in genetic algorithm.It has been proved that the optimized boring parameters can ensure the deformation of piston,and at the same time,can effectively improve the material removal rate.It has been proved that the optimized boring parameters can ensure the deformation of piston,and at the same time,can effectively improve the material removal rate.