Nondestructive Evaluation of Mechanical Properties Using Instrumented Indentation Techniques:Strength, Fracture Toughness, and Residual Stress

摘要

As the demands on structural systems increase, safety evaluationrnbecomes more and more important, and material characterization atrnsystem weak points is essential to assess safety accurately. However,rngeneral methods such as uniaxial tensile tests and CTOD (crack tiprnopening displacement) tests are destructive and thus cannot be appliedrnto systems in use. The instrumented indentation technique wasrndeveloped to overcome this problem. However, current research on thisrntechnique focuses on hardness measurements, and its utility inrnmeasuring the flow property, fracture toughness, and residual stress has not been sufficiently evaluated.rnIn this paper we introduce evaluation methods for flow properties,rnfracture toughness, and residual stress near a weldment. The algorithmrnfor flow property evaluation was verified by comparison withrnexperimental and FEA (finite element analysis) results. The fracturerntoughness model was verified by CTOD results, and the residual stressrnevaluation model was compared with mechanical cutting results.