高温结构可靠性分析的时变响应面法

高温条件下结构的本构方程和承载能力都随时间变化,传统的结构可靠性模型在分析这种时变结构可靠性问题时效率较低.提出一种可用于高温结构可靠性分析的热响应与响应量阈值均随时间变化的时变响应面法.首先,通过引入结构各基本变量与时间的交叉二次函数并结合Box-Behnken试验设计建立结构热响应量的时变模型;进而,以温度为中间变量,建立结构响应量阈值与时间的函数关系,据此得到用随机过程表示的时变极限状态函数.具体给出了基本变量服从正态分布情形下的结构时变可靠度计算方法.算例分析表明该方法切实可行,能够在保证计算精度的基础上大幅提高计算效率.

Time-varying response surface method for high-temperature structural reliability analysis

The constitutive equation and carrying capacity of structure will change over time under high temperature conditions. The traditional structural reliability models are inefficient to solve these time-varying structural reliability problems. A time-varying response surface method with thermal response and response threshold value changing over time was proposed. The method can be used for high-temperature structural reliability analysis. Combined with Box-Behnken experimental design, a cross quadratic function of structure's basic variables and time was introduced for establishing a time-varying model of the thermal structural response. The function of structural response threshold value and time was established by using temperature as intermediate variable. The time-varying structural reliability calculation method was proposed when basic variables are normally distributed. A study case was given to demonstrate the applicability of this method and its greatly enhanced effectiveness besides accuracy.