Scale-bridging Modeling of Microstructural Changes in Concrete and Damage Analysis of Concrete Structures for the Identification of Coda Signals

混凝土微观结构变化的尺度桥接建模和混凝土结构损伤分析，用于识别 Coda 信号

• 批准号: 418917695
• 负责人: Professor Dr. Günther Meschke
• 金额: --
• 依托单位: Lehrstuhl für Statik und Dynamik
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/418917695?language=en
• 关键词: Scale; bridging; Modeling; Microstructural; Changes

The high sensitivity of the coda waves to weak microstructural changes in concrete opens the perspective to identify early-stage damage events that precede macrocracking and severe failure of concrete structures. Detecting such precursor damage in concrete and reinforced concrete structures can serve as an early warning system to take precautionary retrofitting measures to avoid expenses for extensive rehabilitation of engineering infrastructure. However, the state of the coda wave technology for the assessment of the structural integrity of concrete structures is at its early stages. Within the framework of this Research Group FOR 2825, the objective of Subproject RUB1 is to establish a model-based characterization of the degradation of concrete at multiple scales and to enable a classification of the level of damage using simulated and measured coda data. In the first phase of the project, RUB1 developed a tool to generate realistic concrete microstructures and a multiscale reduced-order model for simulating concrete damage. Synthetic coda waves obtained from sampling the virtual concrete specimens were used to train a classifier and to identify specific stages of microstructural changes such as reversible deformation, distributed microcracking and localized macrocracks. In the second phase of the project, first the reduced-order multiscale model for damage simulation will be extended to consider environmental loads such as temperature and moisture. Second, the material scale damage classifier will be extended and enhanced with additional attributes to filter environmental and boundary effects. The third major area of focus is the transfer of coda-characteristics (damage-class and loading-type identifiers) derived at the material scale and specimen scale to the structural scale. Finally, the capability of the model-based framework for the identification of damage will be validated by application to the demonstrator projects.

尾波对混凝土中弱微观结构变化的高敏感性为识别混凝土结构宏观开裂和严重失效之前的早期损伤事件开辟了前景。检测混凝土和钢筋混凝土结构中的这种前兆损坏可以作为一种预警系统，以采取预防性改造措施，避免工程基础设施的大规模修复费用。然而，混凝土结构的结构完整性评估的尾波技术的状态是在其早期阶段。在该研究小组的框架内，为2825，子项目RUB1的目标是建立一个基于模型的表征混凝土的退化在多个尺度，并使使用模拟和测量尾波数据的损害程度的分类。在项目的第一阶段，RUB1开发了一个工具来生成逼真的混凝土微观结构和一个多尺度降阶模型来模拟混凝土损伤。从虚拟混凝土试样取样获得的合成尾波被用来训练分类器，并确定微观结构变化的特定阶段，如可逆变形，分布微裂纹和局部宏观裂纹。在该项目的第二阶段，首先将扩展用于损伤模拟的降阶多尺度模型，以考虑温度和湿度等环境载荷。其次，材料尺度损伤分类器将被扩展和增强，增加额外的属性，以过滤环境和边界效应。第三个重点领域是尾波特征（损伤等级和载荷类型标识符）在材料尺度和试件尺度的结构尺度的转移。最后，基于模型的框架识别损伤的能力将通过应用于示范项目进行验证。