DETERMINATION OF STRESS-STRAIN RELATION USING INSTRUMENTED BALL INDENTATION AT MICRON SCALE

摘要

Indentation with the spherical shape indenter has been used for long time as the way to measure true stress - plastic strain curve and corresponding properties: strain-hardening exponent, strength coefficient, yield strength and other values. A different approach has been used to obtain the desired σ(ε) curve from partial loading-unloading (PUL) force vs depth dependence processing using the analytical solutions, finite element modeling (FEM) and neural networks. The last two methods have primarily laboratory applications, while analytical approach has been used to determine mechanical properties in industrial applications. Automated ball indentation (ABI) [1, 2] is one of those most old established methods, which was mostly used for the pipeline and weld joints control. In current work, we present the results of the application of ABI method for the determination of stress - strain relation in micrometer range.