Dynamic Necking of Notched Tensile Bars: An Experimental Study

Abstract

The mechanics of necking inception in dynamically-stretched notched specimens have been investigated. For that task, a systematic experimental campaign of quasi-static and dynamic tensile tests on martensitic steel specimens has been conducted. Samples with and without notches have been considered. Unlike the quasi-static tests, the dynamically-tested notched samples revealed that, under certain loading conditions, flow localization may develop away from the groove. The experimental results presented in this investigation show that the presence of sharp geometrical imperfections in ductile materials subjected to dynamic loading does not necessarily dictate the necking and fracture locus.

Non-uniform distributions of initial porosity in metallic materials affect the growth rate of necking instabilities in flat tensile samples subjected to dynamic loading

“…Post-mortem examination of the specimens revealed considerable ductility inside the neck for all materials and velocities that these authors tested, the final fracture showing a deep cup and cone which were more acute as the impact velocity was increased. Similar experimental observations have been reported in many other studies in which metallic cylindrical bars were tested dynamically, see for instance the recent papers of Rittel and co-workers [17,18].…”

Why does necking ignore notches in dynamic tension?

“…Experimental results for 90 dynamic tensile notched 15-5 PH (annealed) and 4340 steel specimens are presented, and are shown to follow the trends found in [9], a Corresponding author: merittel@technion.ac.il as shown in Fig. 1.…”

Necking evolution in dynamically stretched bars: New experimental and computational insights

“…In order to prevent from specimen reloading, a momentum trap was brought initially in contact with the loaded flange of the incident bar, whose length was identical to that of the projectile bar. Further details of the experimental arrangement can be found in Rittel et al (2014) and Rotbaum and Rittel (2014). Moreover, a Kirana high speed digital camera was synchronized with the incident bar signals to record the deformation of the specimen during the loading process.…”