高温合金锻件三向残余应力场的超声无损表征与成像方法研究OA

To address the challenge of non-destructively characterizing deep three-dimensional residual stress fields in critical load-bearing hot-section components of domestically developed large wide-body aircraft engines,this study investigates ultrasonic-based methods for non-destructive residual stress characterization and imaging.An ultrasonic acoustoelastic theoretical model capable of describing the influence of arbitrary three-dimensional stresses is established,revealing a quantitative relationship between the relative velocity variations of ultrasonic bulk longitudinal waves and triaxial stresses.By developing an ultrasonic wave-propagation simulation framework for components containing residual stresses,multi-angle ultrasonic transmission data are designed and acquired for representative high-temperature alloy forgings.Two imaging approaches are proposed:a tomographic imaging method based on iterative reconstruction algorithms and an inversion imaging method based on neural networks.The results demonstrate that the tomographic approach can sensitively capture the characteristic"tensile core-compressive surface"stress distribution within the forging and exhibits high sensitivity to process-induced asymmetric distributions.The neural network method,in contrast,shows strong nonlinear fitting capability for complex patterns and yields smaller average errors in high-stress regions.The two methods are complementary,their inversion results remain at the same stress level as the ground truth and effectively reflect the magnitudes and distributions of radial,circumferential,and axial residual stresses within the actual forging.The proposed methodology provides important data support for ensuring the dimensional stability,reliability,and in-service safety of critical load-bearing hot-section components in aero-engines.