论文标题
非线性结构系统的同质性理论 - 结构安全评估的一般基础
The theory of homogeneity of nonlinear structural systems -- A general basis for structural safety assessment
论文作者
论文摘要
该论文开发了一种新颖而通用的方法来表征结构系统的非线性，并为将部分安全因素应用于非线性结构系统提供了数学上的验证基础。自从限制状态理论发展以来，它首次建立了部分安全因素概念与非线性结构系统的可靠性理论之间的必要关键关系。在设计点，已将同质性程度作为非线性度量引入，从而有效地将可靠性指数的数学脱钩到非线性不变性的局部可靠性指数中。通过这种表述，在复杂的非线性结构系统中已经确定了极端非线性情况的关键安全情况。该理论基于可靠性指数的渐近行为产生了两个主要结果。首先，任何非线性结构系统的可靠性指数始终保持上限和下限之间的限制，这可以通过非线性不变的部分可靠性指数的概念来确定。第二个是非线性不变的关键部分安全因素，该概念确保可靠性指数大于任何非线性结构系统中的目标可靠性指数。已经提出了同质性分析来评估复杂的非线性结构系统的安全性。尽管它可以与结构力学中可用的高级计算方法相结合，但并不是专门为工程实践而设计的。提出的理论主要旨在为代码作者提供为非线性结构系统校准部分安全因素的必要程序，并在实践守则中确定过度安全或安全案例。
The paper develops a novel and general methodology to characterize the nonlinearity of structural systems and to provide a mathematically proven basis for applying partial safety factors to nonlinear structural systems. It establishes, for the first time since the development of limit-state theory, the necessary key relationship between the partial safety factor concept and the reliability theory of nonlinear structural systems. The degree of homogeneity has been introduced as a nonlinearity measure at the design point, allowing an efficient mathematical decoupling of the reliability index into nonlinearity-invariant partial reliability indexes. With this formulation, critical safety situations in extreme cases of nonlinearities have been identified in complex nonlinear structural systems. The theory resulted in two main outcomes based on the asymptotic behaviour of the reliability index. First, the reliability index of any nonlinear structural system remains always bounded between an upper and lower bound, which can be determined by the concept of nonlinearity-invariant partial reliability indexes. The second is nonlinearity-invariant critical partial safety factors, a concept that assures a reliability index greater than the target reliability index in any nonlinear structural system. Homogeneity analysis has been suggested to assess the safety of complex nonlinear structural systems. While it can be coupled with advanced computational methods available in structural mechanics, it is not specifically designed for engineering practice. The proposed theory is designed primarily to provide code writers with the necessary procedure for calibrating partial safety factors for nonlinear structural systems, and to identify the over-safe or under-safe cases in the codes of practice.
