Abstract
In this paper, the first, relations between strain at the maximum carrying capacity of the section ε_cr and width-to-thickness ratio of the flange b/f are discussed. And it is shown that the test results were corresponded to the result of the past research on the plate elements. The second, the influences of the parameters (b/f, width-to-thickness ratios of the web D/w, axial load ratios n, material properties of the steel) on the post local bucking behavior are discussed. The summaries are as follows : 1) In the case of b/f√σ_y (σ_y : yield point stress, evaluated in t/cm^2)=13〜15, the load carrying capacity of the sections after flange buckling increases due to strain hardening until web buckling takes place. 2) In the case of b/f√σ_y=26〜30, the load carrying capacity of the sections decreases due to the flange buckling. 3) Three distinct types of the hysteretic behavior are clearly observed from the test results of Series II. The first type shows graduale decrease of the maximum carrying capacity in each cycle of loading. The second type show remarkable decrease of the maximum carrying capacity in each cycle of loading. The last type shows drastic decrease in the maximum carrying capacity at the local buckling takes place. As shown in the table 2, the kind of types depend on the values of b/f, D/w, and n. 4) The decrease in the carrying capacity of high strength steel members is more remarkable than one of the mild steel members.
