Calibration of powder constitutive model using digital image correlation validated for hollow hemisphere of lead zirconate titanate

Abstract

This paper presents the application of digital image correlation to uniaxial and diametral compression tests to identify the Drucker-Prager/cap shear failure and the elastic parameters of a lead zirconate titanate powder (PZT). The calibrated parameters were validated through finite element simulation of the cold isostatic pressing of a hollow hemisphere used in piezoelectric transducers. The results showed that the dilatancy stresses were 50–65% lower than the fracture stresses, demonstrating that adopting the fracture stress may overestimate material cohesion. The simulation using the calibrated model achieved an excellent agreement with the measured geometry, with a difference of only 1.1% in the dimension and 2.0% in the average density. The results highlight how digital image correlation can obtain more accurate parameters with fewer tests. The proposed methodology can be used to calibrate other powder materials, especially those in which dilatancy plays a key role.