EAGER: Understanding Nonlinear Mechanical Behavior in Porous Infrastructure Materials

EARLY概念探索性研究（EAGER）项目将提供对多孔基础设施材料的机械响应行为的深入了解。多孔基础设施材料对于文明生活的基础至关重要，从底层结构基岩到世界上最高的混凝土结构。提高材料效率的社会压力正在扩大这些材料的使用和规格。此外，必须改进对这些材料的监测，以安全和经济地延长材料寿命，并确保国家基础设施的公共安全。然而，多孔基础结构材料的扩展设计和检查的进展受到阻碍，因为它们的机械响应行为的某些方面知之甚少。这项研究解决了现有知识的差距，通过直接观察，使用新的实验技术，可以揭示岩石的微地震启动行为，建立一个新的非线性基础来解释结构健康监测混凝土结构中的振动和波传播响应，并可能提供新的见解时间相关的材料行为，包括混凝土的收缩和徐变。动态介观尺度非线性弹性（DME）的多孔基础设施材料的行为将使用创新的实验测量在两个不同的长度尺度进行研究。该研究由以下工作组成：（i）设计和实施宏观尺度的观察材料的非线性DME行为通过振动研究在不同的环境条件下;（ii）设计和实施微观尺度的观察非线性DME行为通过环境扫描电子显微镜（ESEM）测量在不同的环境条件下;（iii）评估长度尺度之间的观测结果，以制定一个可行的基础，为新的基于物理的现象学理论的DME行为。这项工作的结果将为理解和解释各种多孔工程材料的动态力学响应提供独特的见解和新的基础，并为学术界的广泛领域提供益处。

This EArly-concept Grant for Exploratory Research (EAGER) project will provide enhanced understanding of the mechanical response behavior of porous infrastructure materials. Porous infrastructure materials are critical to the foundations of civilized life, from underlying structural bedrock to the tallest concrete structures in the world. Societal pressures for increased material efficiency are expanding the use and specifications of these materials. In addition, improved monitoring of such materials is necessary to extend material life, safely and economically, and ensure public safety for the nation infrastructure. However, progress toward expanding design and inspection of porous infrastructure materials is hampered because some aspects of their mechanical response behavior are poorly understood. This study addresses the gaps in existing knowledge through direct observations using new experimental techniques that can shed light on the micro-seismic initiation behavior of rock, establish a new non-linear basis to interpret vibration and wave propagation responses in concrete structures for structural health monitoring, and potentially provide new insight about time dependent material behaviors including shrinkage and creep in concrete. Dynamic Mesoscale Nonlinear Elastic (DME) behaviors in porous infrastructure materials will be studied using innovative experimental measurements at two different length scales. The study is composed of the following efforts: (i) Design and carry out macroscale observations of material nonlinear DME behaviors through vibrational studies across environmental conditions; (ii) Design and carry out microscale observations of nonlinear DME behaviors through Environmental Scanning Electron Microscope (ESEM) measurements across environmental conditions; (iii) Evaluate the observations between the length scales to formulate a feasible basis for new physically-based phenomenological theory underlying DME behaviors. The findings of the work will provide unique insight and a new foundation to understand and interpret dynamic mechanical responses of a broad range of porous engineered materials, and as such offer benefits to broad swaths of the academic community.