Impact of notch geometry on dynamic strength of materials

Abstract

The resilience of materials from the notch effect together with subsequent operating life and safety are important factors for the choice of material in industrial manufacture as well as for crash scenarios. The aim of this investigation is to study stress caused by the notch effect for HCT780XD and X5CrNi18-10 at different tensile test strain rates as well as due to various stress concentration factors during a high-speed tensile test. The notch geometries chosen are round, trapezoid, sharp and bore. They are compared to a test specimen without notch. The stress distribution analysis of notches was performed by the finite-element-method (FEM) in order to determine stress concentration factors. The high-speed tensile test was recorded with a high-speed camera. For this purpose, the test specimens were marked with a speckle-pattern, essential for the identification of strain rate via Dantec Dynamics Istra 4D. The influence of the stress concentration rate on parameters like energy, strength and the elongation of break was established and will be reported in the following. The level of the concentration factor leads to negative effects while the strain rate level delivers positive results. On other hand, the stress concentration factor is more important on the parameter than the strain rate. By contrast, Poisson's ratio does not affect the parameters observed.