抄録
The dynamic stress concentration due to circular or semi-circular notches of mild steel strips under longitudinal impact was studied by resistance wire strain gages. The shape of the stress wave incidental to the notched portion was regarded almost as a pulse of which the duration was about 150μsec, though small fluctuations caused by the lateral inertia were observed in the measured stress.
Under such a pulse stress wave, the maximum stress of notched portion was measured, and its ratio to the nominal mean stress determined by one dimensional theory was defined as a dynamic stress concentration factor. As a result, it has been clarified that the dynamic stress concentration factors in the case of long duration (150μsec), of the stress compared with the dimensions of notches, agree with those in the static cases. And with assumption of plane stress, the stress produced in the strip subjected to the longitudinal impact, will be obtained with high accuracy.
