An experimental study of pre-notched clamped beams under impact loading

Abstract

Experiments were conducted aiming to systematically investigate the failure behavior of clamped beams with one pre-notch or two pre-notches under impact loading from a projectile strike. High-speed digital video photography was successfully applied in the structural impact tests to record in real time the hasty scenario of the specimens' deformations and failures. It is observed that even a minor pre-notch in a beam may dramatically alter its dynamic response and failure behavior by making it much easier to break. That is, with the presence of pre-notches, the beam' dynamic response pattern would switch from a large global ductile plastic deformation to a local strength-failure, which evolves from crack initiation and extension to a breakage. In this case, much more plastic dissipation is localized at the pre-notched cross-section(s) and the breakage is caused basically by a Mode I crack extension. The effect of pre-notch is found to be strongly location-dependent and surface-dependent.