基于未确知信息的复杂结构能度可靠性分析

Possibilistic Reliability Analysis for Complex Machinery Structure Based on Unascertained Information

针对钢结构系统的模糊能度可靠性分析中需要较大数据量的问题,提出了基于未确知数学理论处理载荷分布规律的一种新方法,即用未确知有理数表示载荷变量来计算变量的特征值。未确知有理数为最常用的离散型未确知数,可以较为精细地刻画具有不确定性的量,避免只用单一实数点值来表示这种量时产生的信息遗漏和失真。复杂模糊结构系统的可靠性分析中,对含有多个可能失效模式的大型复杂结构系统进行可靠性计算是个难点。采用结构的能度可靠性模型,用优化准则法选取可能的临界元,用增量载荷法确定主要失效模式的极限状态方程,在确定的截集水平下,确定了系统钢结构可靠性指标。通过未确知数学理论和能度可靠性模型的巧妙结合,解决了上述难点并使计算结果更接近实际真值。为工程复杂结构系统可靠性分析探索一种新型的计算模式和方法。

A new method based on mathematical theory possibilistic reliability was put forward to handle the load distribution. This method was used to meet the data needs of possibilistic reliability analysis, which used unascertained rational number to describe the load variables. Unascertained rational number was the most commonly used discrete unascertained number which was used for more precisely describing characterization of uncertainty data and avoided only a single real value omitting and distorting of information. Fuzzy complex structure system reliability which contained a number of possible failure modes was a difficult calculation. The reliability of steel structure system was deter mined by optimizing criteria method and incremental load method. The calculation results are closer to the actual true value by combination of unascertained mathematical theories and possibilistic reliability theories. A new kind of computation model and methods was explored for the complex structure of the system reliability analvsis.