Research And Application Of Different Equivalent Recursion Algorithm In System Reliability Analysis

It is a great advance to design and evaluate civil engineering structures based on the reliability theory.But,this application is only limited to the member level.It is common knowledge that most of the structures are structural systems which are composed of many members.How to find the failure modes and how to calculate the failure probability are two key points in the structural system reliability analysis.The research work in this paper was made around the above two key points and the main results are as follows:The procedure of JC method is edited to calculate the reliability index of the structure members.Considering the relativity among the failure modes,three types of methods are analyzed to how to calculate correlation coefficients of the failure mode.Based on the principle of different equivalent recursion algorithm(DERA),the analytical expression of the equivalent failure mode is deduced,the traditional DERA is modified.The property of the equivalent failure mode is studied from three aspects,the computational precision is improved.The error reason of failure probability of system is caused by the equivalent failure mode is analyzed,the formula of failure probability of system is revised.The DERA combining with the gerneralβboundary method is applied in the identification of system failure mode,not only the major failure mode is not omitted,but also the computational amount is reduced enormously,the efficiency of the identification of system failure mode is upgraded immensely.Based on the equivalent principle of DERA,the formula of system performance function is reconstructed to the limit state surface is deduced,the theoretical foundation of the system performance function reconstruction is establishedThe DERA is applied in the calculation of system failure probability,and compared with the probability network estimation technique,the wide interval estimation method,the narrow interval estimation method and the numerical different method.The high precision and efficiency of DERA is embodied.In order to study the influence between system failure probability and the weakness failure mode in the series structure system,the sensitivity of the ratio between the weakness failure probability and the system failure probability is studied.