Enabling the Design of Failure-Tolerant Complex Engineered Systems using New Network-Based Modeling, Analysis, and Simulation Formalisms

许多构成我们社会结构的工程系统，如电网、商用飞机或自动驾驶汽车，本质上是难以建模和分析的。在这样的复杂系统中，许多相互作用的子系统通常是独立设计、管理和工程的。这种“按子系统设计”的方法降低了设计过程的成本和复杂性，但在系统集成和运行测试之前，阻止了子系统之间意外的、紧急的交互的发现。该奖项通过关注故障模式如何依赖于子系统之间的连接以及控制这些子系统物理行为的变量和参数，探索了复杂工程系统失效分析的新方法。虽然在以前的研究中，复杂工程系统的网络模型已经被引入来解决这个问题，但基本的限制仍然是完全依赖于组件之间的物理和功能依赖。本研究旨在产生一套指标，以帮助工程师量化复杂工程系统的故障容忍度，而无需进行完整的系统仿真，这在许多情况下既不可行也不实际。本项目特别介绍了一种基于相互依赖网络容错的鲁棒设计新方法。该方法明确地处理了物理架构和行为、基于物理的关系，这些关系有助于系统对故障的容忍度。该方法结合了复杂网络的中尺度特性，即模块化，以理解组件的架构及其基于物理的关系如何具有创建稳定性和容错性的重要功能。该项目将首先引入基于设计元素之间关系稳定性的稳健设计的新概念。这代表了对稳健设计的一个重要的概念转变，从单纯的组件可靠性转向考虑部件行为的连通性。然后，该项目将引入一种基于网络的方法和仿真环境，能够计算复杂工程系统的鲁棒性。本文将介绍一套测量方法，这些方法虽然是单一的量，但却能全面地捕捉复杂工程系统的失效行为，不仅是在名义行为和失效之间的相变，而且是在此之前和之后。

Many engineered systems that form the fabric of our society, such as power grids, commercial aircraft, or self-driving cars, are by nature difficult to model and analyze. In such complex systems, many interacting subsystems are often independently designed, managed and engineered. This "design-by-subsystem" approach reduces the cost and complexity of the design process, but prevents the discovery of unexpected, emergent interactions between subsystems until the system is integrated and tested in operation. This award explores new methods of failure analysis for complex engineered systems by focusing on how the failure modes depend on the connections between subsystems and the variables and parameters governing the physics-based behaviors of those subsystems. While in previous research network models of complex engineered systems have been introduced to address this issue, the fundamental limitation remains the exclusive reliance on physical and functional dependencies between components. This research aims to produce a set of indicators to assist engineers in quantifying the failure tolerance of complex engineered systems without going through the expense of a complete system simulation, which in many cases is neither feasible nor practical. This project specifically introduces a new approach to robust design based on failure tolerance of interdependent networks. The approach explicitly addresses both physical architecture and behavioral, physics-based relations as contributing to the system's tolerance to failure. The methodology incorporates a mesoscale property of complex networks, namely modularity, to understand how the architecture of components and their physics-based relations have an important function of creating stability and failure tolerance. The project will first introduce a new conceptualization of robust design based upon the relational stability between design elements. This represents an important conceptual shift in thinking about robust design, moving away from component reliability alone towards consideration of the connectivity of the behavior of parts. The project will then introduce a network-based methodology and simulation environment capable of calculating the robustness of a complex engineered system. A set of measures will be introduced, which, while being single quantities, holistically capture the failure behavior of the complex engineered system not just at phase transition between nominal behavior and failure but before and after that as well.