Measurement And Calculation Of Residual Stress Field In Aeronautic Blank

The release of residual stresses in aeronautic blank is the primary factor that causes the distortion of parts during cutting processing. Therefore it is of great interest to study the residual stress field distribution for controlling the distortion. A model with typical characteristic residual stress field was given, the HDM (hole drilling method) was used to measure the residual stresses, and various interpolation methods were developed to calculate the residual stress field. The major research works are listed as following:1. The model of the HDM was given and simulated using the FEM (finite element method). The relationship between the depth of the blind hole and the release of the residual stresses has been presented. The result from the simulation is very coincidental with the one in reference;2. A model with typical characteristic residual stress field was established using the FEM. One initial criterion was developed to study the residual stress field. According to the initial criterion, the measurement sites are chosen by regular means and the residual stress field was inversed using the interpolation methods such as linear method, cubic method, spline method or nearest method. The measurement sites can also be chosen by irregular means and the residual stress field was inversed using the interpolation methods such as inverse distance weighting method or radial basis method;3. A refinement criterion based on the stress gradient was developed. Based on the refinement criterion, the measurement sites were increased and the inversive result was refined. Comparing the inversive results with the experimental ones, we got the precision of those interpolation methods;4. The residual stresses in one aluminum alloys plate were measured through HDM and interpolation methods mentioned above was used to calculate the residual stress field. The interpolation results were compared with test determination results and the interpolation results coincide well with the test ones. The machining process was simulated with FEM and the distortion of FEM model is similar with the real condition.