Experiments on stress-triaxiality dependence of material behavior of aluminum alloys

A Continuum Damage Model Based on Experiments and Numerical Simulations—A Review

“…Since uniaxial tension tests with differently pre-notched specimens are characterized by different hydrostatic stress states in the small region between the notches (Brünig et al 2011b(Brünig et al , 2008Driemeier et al 2010), these experiments can be used to determine the hydrostatic-stress-dependent parameter a/c appearing in the yield criterion (2.11). However, in these tests with pre-notched specimens stress and strain fields are not homogeneous and only quantities in an average sense can be evaluated from these experiments.…”

“…Decrease in notch radius will lead to an increase in stress triaxiality in the specimen's center up to η = 1/ √ 3. In addition, shear specimens (blue) elongated in uniaxial tension test will lead to stress triaxialities of about η = 0.1 when notches in thickness direction are added in the central part (Brünig et al 2011b(Brünig et al , 2008Driemeier et al 2010) whereas without additional notch they will also lead to onset of damage at nearly η = 1/3. However, with these flat specimens taken from thin sheets elongated in uniaxial tension tests only the stress triaxialities shown in Fig.…”

“…Tension tests with these specimens have been performed (Bao and Wierzbicki 2004;Gao et al 2010) leading to shear mechanisms in their centers. Similar specimens have been developed and tested by Brünig et al (2008);Driemeier et al (2010). Furthermore, to be able to take into account other regions of stress triaxialities butterfly specimens have been manufactured (Bai and Wierzbicki 2008;Dunand and Mohr 2011;Mohr and Henn 2007) which can be tested in different directions using special experimental equipment.…”

Ductile Failure Modelling: Stress Dependence, Nonlocality, and Damage to Fracture Transition

“…According to Mirone and Corallo (2010), the phenomenon of ductile failure is influenced by the relation with the variables from the stress-strain characterization, and failure predictions are better described by plastic strain, stress triaxiality, and Lode angle parameters. An experimental program to study the influence of the stress tensor invariants in ductile failure was presented by Driemeier et al (2010). This methodology can be seen as an efficient tool to investigate the effects of the stress intensity, stress triaxiality, and Lode angle.…”

Stress state dependence of ductile damage and fracture behavior: Experiments and numerical simulations

“…Moreover, specimens with new geometries have been designed to be able to analyze stress states with nearly zero stress triaxiality. These specimens have been uniaxially loaded in tension tests leading to shear mechanisms in their centers [16,28,31,33]. However, in these experiments with specimens taken from thick sheets (more than 3 mm thickness) rotation of the center has been observed leading to increase in additional tension stresses which causes increase in stress triaxiality.…”