Abstract
As the typical example of the tension member of which stress concentration must be considered, a plate with a round hole was adopted, and the behavior was investigated until its ultimate state theoretically using the numerical analysis by finite element method to the elastic-plastic range on the basis of the flow theory and experimentally. And it has been shown as the case of the member of which stress concentration is negligible that the elongation capacity of the steel plates of which section area change along their length was controled by the yield ratio of the material used. The larger the value of the yield ratio, the smaller the elongation capacity of the member. It may be said from this point of view that it should be careful when the high yield strength steel be used in tension member bolted or rivetted at its end connection or in tapered or notched shape because the high yield strength steel generally has the high yield ratio.
