For spatial , ideal elasto - plastic girder - pane structure system , using the stochastic finite element method , the static response of structural system is analyzed . taking redistribution of internal forces into account , safety margin functions of failure modes are established . using the advanced branch - and - bound method , the significant failure modes are identified , and the reliability of structural system is evaluated by pnet method 對(duì)空間理想彈塑性梁板體系結(jié)構(gòu),采用隨機(jī)有限元計(jì)算結(jié)構(gòu)系統(tǒng)的響應(yīng)量;考慮內(nèi)力重新分配,建立失效模式的安全余量方程,用驗(yàn)算點(diǎn)法計(jì)算失效模式安全余量的可靠性指標(biāo);用改進(jìn)的分枝限界法,尋找主要失效模式:然后用pnet法計(jì)算結(jié)構(gòu)系統(tǒng)的可靠性指標(biāo)(或失效概率) 。