EAGER: A Reassessment of the Notion of Damage of Materials

这项早期概念探索性研究（EAGER）奖研究了一种完全不同的方法来表示可能改变力学领域的材料损伤。结构材料损伤的评估和修复是科学家和工程师面临的一个至关重要的问题。大坝、桥梁、隧道和建筑物的热循环、湿气、电磁辐射和周期性机械负荷造成的破坏后果可能是灾难性的。然而，由于需要了解这些施加载荷的历史，预测这些结构部件的剩余寿命是具有挑战性的。该研究将为基于数量（如身体密度）的损伤增长预测提供一种新的表示，这些数量完全由身体的当前结构决定。这种方法对大量高分子材料和混凝土等脆性材料具有重要意义。如果成功，该研究将对许多对材料和结构损伤的评估和修复具有技术意义的问题产生重大影响。目前大多数评估损伤的方法都依赖于使用有效的损伤参数，而这些参数总是缺乏适当的物理解释。使问题进一步复杂化的是，使用基于应力或应变等量的损伤标准，这些量的值不一定取决于身体的当前状态。使用完全由身体当前状态决定的量的值，而不是需要来自特殊参考状态的信息的物理量的相对值，将会更有意义和更合适。在当前状态下完全确定的量的例子有密度、温度、微观结构特征等。研究的目的是考虑到这些数量在身体的当前状态，以发展本构关系，可以有意义地预测损伤的发生。

This EArly-concept Grant for Exploratory Research (EAGER) award investigates a radically different approach to represent the damage of materials that can potentially transform the field of mechanics. The assessment and remediation of damage in structural materials is a critically important issue facing scientists and engineers. The consequences of damage due to thermal cycling, moisture, electromagnetic radiation, and cyclical mechanical loading on dams, bridges, tunnels and buildings can be catastrophic. However, predicting the remaining lifetime of these structural components is challenging due to the need to know the history of these applied loads. The research will provide a new representation for the prediction of damage growth based on quantities, such as the density of the body, that are completely determined by the current configuration of the body. Such an approach is meaningful for a large class of polymeric materials and brittle materials such as concrete. If successful, the research will have a significant impact on numerous problems that have technological significance for the assessment and remediation of damage in materials and structures.Most of the current methodologies to assess damage resort to using effective damage parameters that invariably lack proper physical interpretation. Complicating matters further is the use of criteria for damage based on quantities such as stress or strain, quantities whose values cannot necessarily be decided based on the current state of the body. It would be much more meaningful and appropriate to use values of quantities that are completely determined by the current state of the body rather than the relative value of a physical quantity that requires information from a special reference state. Examples of quantities that are completely determined in the current state are the density, temperature, microstructural features, etc. The aim of the research is to take into account such quantities in the current state of the body to develop constitutive relations that can meaningfully predict the onset of damage.