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，本质上很难建模和分析。在这样的复杂系统中，许多相互作用的子系统往往是独立设计、管理和设计的。这种“逐个子系统设计”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，可以防止发现子系统之间意外的、紧急的交互作用。该奖项探索复杂工程系统故障分析的新方法，重点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基于物理的行为的变量和参数。虽然在以前的研究中已经引入了复杂工程系统的网络模型来解决这个问题，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。这项研究的目的是提出一套指标来帮助工程师量化复杂工程系统的容错能力，而不需要进行完整的系统仿真，因为在许多情况下，这是既不可行也不实用的。本项目具体介绍了一种基于相互依赖网络容错的稳健设计新方法。该方法明确地解决了物理体系结构和行为、基于物理的关系，这些关系有助于系统对故障的容错。该方法结合了复杂网络的中尺度属性，即模块化，以了解组件的体系结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。该项目将首先引入一种基于设计元素之间的关系稳定性的稳健设计的新概念。这代表着思考稳健设计的重要概念转变，从仅考虑部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模拟环境，能够计算复杂工程系统的健壮性。将引入一套措施，这些措施虽然是单量，但不仅全面地捕捉了复杂工程系统在名义行为和失效之间的相变时的失效行为，而且还捕捉到了这之前和之后的失效行为。

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.