考虑腐蚀影响的钢结构轴压构件可靠度预后分析

Reliability prognosis analysis on axial compressed members of steel structures with corrosion into consideration

针对腐蚀会严重影响结构的性能甚至使其崩塌失效这一事实,基于蒙特卡洛方法和Weibull模型提出了钢管轴压构件考虑腐蚀的时变可靠度预测方法.首先利用幂函数模型替代钢材的实际腐蚀过程计算腐蚀厚度,其次利用蒙特卡罗方法计算不同年限时的腐蚀钢管轴压构件的可靠度,同时依据Weibull模型提出钢管在腐蚀作用下的可靠度随时间变化预测曲线.最后通过实际算例验证了所提方法的有效性.结果表明:Weibull模型可以较好地模拟腐蚀影响下的可靠度随时间变化的模型;提出的时变可靠度曲线与理论值吻合较好;考虑腐蚀影响的可靠度值在一定年限以后将会小于目标可靠度.

Corrosion is one kind of damage or failure modes occurred frequently in steel structures,which can usually lead to structural deterioration and even collapse failure. Therefore,this paper proposes a time- dependent reliability analysis approach by integrating Monte Carlo method and Weibull model. More specifically,the power function is firstly used to replace the practical steel corroding process in order to calculate the section area under corrosion; secondly,Monte Carlo method is used to calculate the reliability of axial force members of corrosion steel structure; simultaneously,the Weibull model is utilized to fit the forecast curve of reliability- time; finally,a practical simulation is performed to validate the proposed method. The results show that： Weibull model can effectively simulate the time- dependent reliability process in the corrosion environment; the proposed time- dependent reliability analysis results are in a good agreement with theoretical values; and reliability value of the proposed method will be smaller than the target reliability value of design structural presented.