Elastic and plastic deformation behavior analysis in small punch test for mechanical properties evaluation

In order to estimate deformation and mechanical properties of material accurately, elastic and plastic deformation behavior of small punch test was discussed in this paper. A two-dimensional finite element model was established based upon the Gurson-Tvergaard-Needleman(GTN) equation. According to the integration of load—displacement curves with different displacements, the evolution of elastic energy was obtained. The results show that the elastic energy increases quickly in the initial region and tends to be an approximate constant during the plastic bending phase. Meanwhile, an obvious change of the slope of load—displacement curve can be found in the elastic-plastic transition region. The macroscopic deformation and fracture feature were also discussed in order to verify the deformation analysis. Finally, the yield strength, tensile strength and elongation of AISI304 were obtained based on the analysis of deformation energy and percent fracture deflection. The results have a good agreement with that of conventional tensile tests, which may provide a theoretical basis of small punch analysis.