EAGER: A Reassessment of the Notion of Damage of Materials

EARLY概念探索性研究奖（EAGER）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。由于热循环、潮湿、电磁辐射和大坝、桥梁、隧道和建筑物上的周期性机械载荷而造成的损害后果可能是灾难性的。然而，预测这些结构部件的剩余寿命是具有挑战性的，因为需要知道这些施加的载荷的历史。该研究将提供一种新的表示方法，用于预测基于数量的损伤增长，例如物体的密度，这些数量完全由物体的当前配置决定。这种方法对于大类聚合物材料和脆性材料如混凝土是有意义的。如果研究成功，将对许多问题产生重大影响，这些问题对材料和结构的损伤评估和修复具有技术意义。目前的大多数损伤评估方法都采用有效的损伤参数，而这些参数总是缺乏适当的物理解释。使问题更加复杂的是使用基于应力或应变等量的损伤标准，这些量的值不一定能根据物体的当前状态来确定。使用完全由物体的当前状态决定的量的值，而不是需要来自特定参考状态的信息的物理量的相对值，会更有意义和更合适。在当前状态下完全确定的量的例子是密度，温度，微观结构特征等。研究的目的是考虑到这些量在当前状态下的身体发展本构关系，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.