Abstract:  The rupture in the middle of bulk cargo is due to the corrosion and fatigue of components in long term usage‚which leads the section modulus to reduce and the general longitudinal strength to weaken．In this paper‚through the research of the rupture of an old bulk cargo in middle‚a new method named “test -calculated section modulus method” was proposed．The method is easy to realize．Comparing with the “zone thickness-survey method”‚the method proposed here proves reasonable．

Key words: general longitudinal strength, section modulus, rupture