Stress Analysis And Process Improvement Of Low Pressure Turbine Case

As a key part of the the low-pressure compressor power turbine,the low-pressure turbine case is designed to constrain the low-pressure turbine guide vane assembly and serve as the assembly reference of the low-pressure turbine guide.The low-pressure turbine case is a large thin-walled porous multi slot case,which is easy to be deformed due to the redistribution of internal residual stress during the manufacturing process,thus affecting the performance of the aeroengine.In order to reduce the internal residual stress of the low-pressure turbine case,this paper takes a certain low-pressure turbine case as the research object,formulates the processing route,carries on the massive examination,the analysis,the optimization and the verification to the test piece,and carries on the systematic research to the deformation control method of the low-pressure turbine case.The main research contents are as follows:(1)Preliminarily formulate machining process route,trial produce and measure deformation data of test piece.According to the structural characteristics of low-pressure turbine case,aiming at reducing the stress,preliminarily establishes the technological process,and makes trial production.In the process of trial production,the residual stress of the main working procedure of the test piece was measured,and calculated the deformation data(2)Finite element simulation analysis.In order to explore the influence of turning on the residual stress of the parts and find out the cause of the deformation,this paper uses ABAQUS software to carry out the finite element simulation analysis on the key process of the test piece,and obtains the cloud diagram of the residual stress and the deformation of the parts after the main process of the parts,and obtains the approximate distribution form of the residual stress,the change of the stress and the deformation of the parts.The simulation results show that the turning process affects the surface stress of the test piece.(3)Process optimization.Based on the measured and simulated data,a method to control the internal residual stress of parts is developed,and the change of internal residual stress before and after optimization is compared and analyzed by means of X-ray stress detection.Finally,the final dimension of parts is measured to evaluate the effect of improving the quality of parts after the reduction of residual stress.