EAGER: Understanding Nonlinear Mechanical Behavior in Porous Infrastructure Materials

这个探索性研究（EAGER）项目的早期概念资助将加强对多孔基础设施材料力学响应行为的理解。多孔基础设施材料对文明生活的基础至关重要，从底层的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，为了安全、经济地延长材料寿命，确保国家基础设施的公共安全，改进对这些材料的监测是必要的。然而，扩大多孔基础设施材料的设计和检查的进展受到阻碍，因为他们的力学响应行为的某些方面知之甚少。本研究通过使用新的实验技术直接观察解决了现有知识中的空白，这些技术可以揭示岩石的微地震起震行为，建立新的非线性基础来解释混凝土结构中的振动和波传播响应，用于结构健康监测，并可能为混凝土中的收缩和徐变等随时间变化的材料行为提供新的见解。动态中尺度非线性弹性（DME）行为在多孔基础材料将研究采用创新的实验测量在两个不同的长度尺度。本研究主要包括以下工作：(i)通过不同环境条件下的振动研究，设计并开展材料非线性二甲醚行为的宏观观测；（ii）通过环境扫描电子显微镜（ESEM）在不同环境条件下的测量，设计并开展非线性二甲醚行为的微观观测；（iii）评估长度尺度之间的观测结果，为二甲醚行为的新的基于物理的现象学理论建立可行的基础。这项工作的发现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，并因此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.