Numerical Study on the Effect of Biaxial Surface Stresses on the Measurement Accuracy of Mechanical Properties in A516 Using Indentation

Accuracy in determination of mechanical properties in industrial parts is a major issue in engineering. Various methods have been introduced to estimate the mechanical properties of the industrial parts, and each has its own features and limitations. The present research investigates the accuracy of Instrumented Indentation Technique (IIT) with Kim’s model in determining mechanical properties, including elastic modulus, yield stress, and work hardening of the A516 steel samples having surface stresses. To this end, some 3D simulations, using IIT on the steel sample with different surface stress state, were performed, and the method’s error in comparison to the initial assumed values were obtained. The results show that the surface stresses significantly affect the error in determining the materials’ properties, and the error in samples with tensile surface stress is more than that of samples with compressive one. To validate the results, some experimental samples with specified initial stress were prepared, which measured mechanical properties by the IIT and then were compared with the tensile test results.