Sensitivity Analysis of Brinell Hardness Number to Material Properties of Structural Steel: A Numerical Study

Hardness is not a fundamental property of a material but it is related to the elastic and plastic properties of the material. Hardness of a material can be determined from indentation hardness tests. Brinell hardness test is one of the commonly used macro-indentation hardness test types to quantify the hardness of a material. In this study, the sensitivity of Brinell Hardness Number (BHN) to the material properties of structural steels that exhibit a plastic plateau in their true stress-strain curve is analysed. Four basic structural steel material properties, Young’s modulus (EE), yield strength (σσyy), ratio (αα) between the strain at beginning-point of strain hardening (εεssss) and the yield strain (εεyy) and strain hardening exponent (nn) are considered for the sensitivity analysis. By identifying the sensitivity of hardness to these material properties, an inverse analysis method based on a hardness test can be developed to identify the unknown steel materials. For a given material combination, the loaddisplacement curve of macro-indentation can be developed using the Finite Element (FE) simulation. For that, a 2D axisymmetric nonlinear FE model is developed using finite element software package ABAQUS and validated using past experimental data. Then BHNs are calculated for selected material combinations and variation of BHN with each material property is obtained. Considering the relationships between material properties and BHN, the sensitivity of BHN to each material property is calculated. Finally, a comparison is made for the sensitivity of hardness by considering all four material properties.