Research On The Evolution Law Of Residual Stress In Marine Diesel Engine Block Considering Process Genetic Characteristics

Diesel engine block is one of the key parts of marine diesel engines,and its reliability and accuracy retention in the production process is an important standard that reflects the level of diesel engine manufacturing technology.Diesel engine block will be accompanied by the generation of residual stress during the manufacturing process.Residual stress is one of the most important reasons for the accuracy retention and reliability of the block during its service life.The release of residual stress will also cause the block to be critical.Serious problems such as cracking and deformation of the part.At present,the research on the residual stress of large castings is mainly conducted from multiple processes,including the residual stress in the casting stage,the residual stress in the processing stage,and the residual stress after annealing and heat treatment.The residual stress is related to conduct a more detailed study,and there is a lack of research on the superposition,influence and evolution of the residual stress between the various processes.In view of the above problems,the study of the residual stress in the diesel engine block in the process of processing and manufacturing,accurate understanding and grasp of the distribution and evolution of residual stress is an important prerequisite for the residual stress analysis of the block.This thesis takes a certain type of marine diesel engine block as the research object,and carries out the following research.1.NX12.0 and Hyper Mesh were used to model and mesh the diesel engine block and its casting system,and the block mesh was successfully imported into the casting finite element software of PROCAST,and the corresponding process parameters and program operation parameters were set to finally obtain the residual stress field and temperature field distributions in the block casting stage.2.The effects of pouring temperature and falling sand temperature on the residual stress field,cooling rate and temperature field of the block were studied.3.On the basis of the residual stress field after the completion of the shake-out,the residual stress field was imported into the ABAQUS4.finite element software for the annealing heat treatment simulation of the diesel engine block with casting residual stress,and the process parameters that have a large impact on the residual stress of the block were optimized.The residual stress values in various areas of the block were significantly reduced and the stress distribution was more uniform,with fewer areas of stress concentration.5.Comparing the results of the numerical simulations with the experimental data,it is found that the data between the two are in good agreement and thus the research method of numerical simulation is feasible to achieve the analysis and study of the dynamic evolution of the residual stresses from casting to heat treatment.In this thesis,numerical simulations of the block under different process parameters are realized on the PROCAST and ABAQUS platforms,providing process designers with new methods of improving and optimizing process,reducing production costs and increasing the service life of marine diesel engines compared to the traditional "trial and error" method.Therefore,the research results are of great theoretical significance and high practical value.