Study on influence factors of small punch test based on ductile damage numerical analysis

A finite element model (FEM) for small punch test (SPT) specimen damage numerical analysis was established based on Gurson-Tvergaard-Needleman (GTN) ductile damage constitutive equations. SPT for SUS304 was performed at room temperature on round specimens with dimension of. The validity of FEM was proved by load-displacement (L-D) curves and rupture location from experiment and simulation. Effects of friction coefficient, sample thickness, steel ball diameter, center hole diameter of the lower die and punching velocity on SPT results were analyzed by finite element analysis (FEA). The results show that the five factors mentioned above have significant influences on L-D curve, ultimate load, rupture time, initial crack and necking location of SPT specimen. Meanwhile, the current deficiency of simulation for SPT was pointed out and overcomed, the acquired conclusions guide the future healthy development of SPT technique.