Numerical investigation of constraint effects on ductile fracture in tensile specimens

Abstract

This study explores the capabilities of a computational cell framework into a 3-D setting to

An Analysis of the Tvergaard Parameters at Low Initial Stress Triaxiality for S235JR Steel

“…It mainly concerns emergency states observed in structural ship elements made of ship steel, and other elements made of normal strength steel. It should be noted that the GTN material model is being continually developed, (see, for instance, Nahshon and Hutchinson (2008), and there are still some problems that need to be solved, as shown in Ruggieri (2004). In numerical simulations performed for structural steel elements, the main drawback is the lack of standardized GTN microstructural parameters, which makes the GTN model difficult to use for common engineering calculations.…”

Assessment of the Von Mises Stresses and Stress Triaxiality in Notches Using Modified Tensile Specimens

“…Derpenski and Seweryn 15 tested 24 combinations of R/ϕ min , ranging from 0.038 to 5. Moreover, the values of R/ϕ min found in the literature are 0.167, 0.2, 0.24, 0.25, 0.312, 0.333, 0.5, 0.667 0.78, 1.0, 1.5 12,[16][17][18][19][20] .…”

“…The standard specimen is a cylindrical bar (smooth round bar) based on the ASTM E8/E8M standard 14 . Several studies were carried out with different diameters and notch radii 12,[15][16][17][18][19][20] . As the minimum diameter varies for each study, it is interesting to use the ratio of the radius (R) and minimum diameter (ϕ min ).…”

“…Studies show that it is possible to obtain the critical plastic fracture strain ε p,crit relative to stress triaxiality, Equation 1 18,[20][21][22][23][24] . The parameters α and β, Equation 1, are constants of the material and can be calibrated using results of tensile tests with different notches 20 . Some authors consider a β constant equal to 1.5 [22][23][24] .…”

“…However, the best option is to calibrate them using the values of ε p,crit , σ m , and σ e obtained for the instant of crack propagation onset. Both Bao 18 and Ruggieri 20 consider the instant before the stress decreases, of the true stress (σ) vs. true strain (ε) curve. Bao 18 used the element located in the center of the specimen.…”