The panels of hull girder may collapse or buckle before it reaches the yield stress . the curve of the stress - strain is usually constituted by stable zone - , non load - shedding zone and load - shedding zone 并且船體截面的組成單元(一般是加筋板單元)在達(dá)到材料屈服應(yīng)力之前還可能發(fā)生多種形式的屈曲。