Nanoindentation techniques are commonly used to characterize nanomechanical properties of microscaled and nanoscaled materials. Nanoindentation using a cylindrical flat-tip indenter has a constant contact area which makes it a reliable source to find material’s yield strength as well as other mechanical properties. However, an angular misalignment of the indenter with the specimen results in experimental error. In this work, the effects of angular misalignment on the nanoindentation testing with a cylindrical flat-tip indenter were numerically analyzed. A three-dimensional nanoindentation solid model was generated, computer modeling based on finite element analysis was conducted. The angle of misalignment ranged from 0° to 1°. Young’s modulus and hardness were evaluated. Based on the hemispherical stress–strain distribution assumption of an elastic plastic indentation, corrected depths and modifiers were proposed for adjusting material’s 0.1% offset and 0.2% offset yield strengths. Low carbon steel AISI 1018 was selected as sample material for indentation testing and modeling validation.

Material property measurements at the micro-/nanoscale are required for within many materials systems, such as thin-films, coatings, nanostructured materials, and interface/interphase. An innovative approach through micro-/nano-indentation testing with a cylindrical flat-tip indenter and coupled with computer modeling was proposed to characterize the material's elastic–plastic properties. A mechanical model proposed for directly extracting the yield strength of the tested materials, based on the hemi-spherical stress–strain distribution assumption, was analytically derived and numerically validated. Specimens being tested are aluminum alloy, low carbon steel, and alloy steel. A micro-/nano-indentation solid model was constructed and computer modeling was conducted. The load point in the indentation load–depth curve and the modifier for extracting the yield strength were identified through computer modeling and validated by indentation tests. The material properties measured by indentation were compared with tensile tests. The indentation testing errors induced by residual stresses in specimens were investigated by a residual stress measurement system.