CAREER: Robust Computational and Experimental Simulation of Mechanical Systems under Extreme Events

该学院早期职业发展项目的研究目标是开发一种新的理论框架和计算方法来模拟极端事件下结构系统的失效过程。结构失效过程的计算机模拟在许多应用中都是非常有价值的：(1)针对极端事件的基于性能的结构设计；(2)结构失效的取证检验；(3)灾后决策支持中的储备能力评估等。但由于失效过程固有的复杂性和敏感性，现有的计算工具无法可靠地模拟失效过程，以便工程师放心使用。这项研究项目将采用一种完全不同的方法来模拟失效过程，整合了动力系统和控制理论、统计力学和热力学以及本构模型理论的思想。这种融合的关键将是一种新的混合拉格朗日形式主义。这种方法将捕捉到失效过程的基本物理过程，从而产生更好的数学模型和更有效的数值算法来进行稳健的模拟。计算机模拟将使用一个新的物理实验程序进行验证，其中将使用专门开发的最优控制来获得稳健的数据。该项目的成功完成将提供实用工具，工程师可以常规使用这些工具来评估极端事件下结构系统的性能。该项目将涉及与四个行业伙伴的合作，以促进将这些工具迅速和无缝地转移到实践中。根据研究部分的跨学科性质，在该项目的教育部分，将在本科三年级开发一门新课程，其目的是在统一的框架内将本科课程中的不同学科联系在一起。此外，结构失效的数值模拟将通过基于网络的计算机游戏和为TeachEngineering数字图书馆开发的单元来激发K-12学生对工程的好奇心，TeachEngineering数字图书馆是美国国家科学基金会S数字图书馆的一部分。

The research objective of this Faculty Early Career Development (CAREER) Program project is to develop a novel theoretical framework and a computational methodology to simulate failure processes in structural systems under extreme events. Computer simulation of failure processes in structures is invaluable in many applications ? (1) performance-based design of structures for extreme events, (2) forensic examination of structural failures, (3) assessment of reserve capacities in post-disaster decision support etc. But due to the inherent complexity and sensitivity of failure processes, current computational tools are unable to simulate them reliably for engineers to use with confidence. This research project will adopt a fundamentally different approach to simulation of failure processes, integrating ideas from dynamical systems and control theory, statistical mechanics and thermodynamics, and constitutive modeling theory. The key to this integration will be a new mixed Lagrangian formalism. This approach will capture the essential physics of failure processes, leading to better mathematical models, and more efficient numerical algorithms for robust simulation. Computer simulations will be validated using a novel program of physical experiments, where specially developed optimal controls will be utilized to obtain robust data.Successful completion of the project will provide practical tools that engineers can use routinely for assessing the performance of structural systems under extreme events. The project will involve collaboration with four industry partners to facilitate rapid and seamless transfer of these tools to practice. In line with the interdisciplinary nature of the research component, in the educational component of this project, a new course will be developed at the junior undergraduate level, whose purpose will be to tie different subjects in the undergraduate curriculum together within a unifying framework. Furthermore, numerical simulations of structural failures will be used to arouse engineering curiosity in K-12 students, through a network-based computer game, and through units developed for the TeachEngineering digital library, which is part of the NSF?s Digital Libraries collection.