Energy dissipation-based approach to stochastic fatigue of concrete considering interacting time and temperature effects

考虑相互作用的时间和温度效应的基于能量耗散的混凝土随机疲劳方法

• 批准号: 471796896
• 负责人: Professor Dr. Rostislav Chudoba
• 金额: --
• 依托单位: Lehrstuhl und Institut für Massivbau
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/471796896?language=en
• 关键词: Energy; dissipation; based; approach; stochastic

The need to drastically reduce material consumption and increase the service life of engineering structures urgently requires higher material utilization, accompanied with intelligent maintenance, repair and recycling concepts. The overall objective of the research proposal is to support the necessary innovative development in structural concrete design by deepening the knowledge of the material and structural behavior in the whole range of interacting loading and environmental attack scenarios during the structure’s lifetime. While high-cycle fatigue of metals has been thoroughly studied and scientific results have progressed to engineering practice by providing reliable predictions of fatigue lifetime, the fatigue damage propagation mechanisms in concrete are yet to be fully understood. In spite of a remarkable progress in recent years made in modeling and characterizing the concrete fatigue behavior, many open questions remain that need to be fundamentally addressed in order to develop a deep and general insight into the phenomenology of concrete fatigue. The scientific goal of the research is to develop advanced, thermodynamically consistent numerical modeling approaches and characterization methods that can capture the interplay of dissipative mechanisms governing fatigue behavior on a broader basis than currently possible. To achieve this goal, the existing common meso-macro modeling platform, which reflects fatigue behavior in terms of local cumulative strain evolution, will be extended to include the influence of temperature, loading rate, and time-dependent material changes. The theoretical and numerical developments will be validated by a systematic experimental program providing multiple observation perspectives to the studied phenomena. To maximize the relevance of the research for engineering practice, the randomness inherent to fatigue loading and local material properties will be captured using advanced methods of probabilistic modeling that will be used for statistical characterization of fatigue behavior in terms of S-N curves, fatigue crack propagation criteria, effect of loading sequence and fatigue creep development. This characterization will serve as a basis for refined design and assessment rules in engineering codes.

为了大幅降低材料消耗，提高工程结构的使用寿命，迫切需要更高的材料利用率，并伴随着智能维护、维修和回收的理念。研究建议的总体目标是通过加深对结构在整个生命周期内相互作用的载荷和环境攻击场景中的材料和结构行为的了解，支持结构混凝土设计中必要的创新发展。虽然金属的高周疲劳已经得到了深入的研究，科学结果也通过提供了可靠的疲劳寿命预测而进入了工程实践，但混凝土中的疲劳损伤扩展机制还没有完全被了解。尽管近年来在混凝土疲劳行为的建模和表征方面取得了显著的进展，但仍有许多悬而未决的问题需要从根本上解决，以便对混凝土疲劳的现象学有一个深刻而普遍的认识。这项研究的科学目标是开发先进的、热力学上一致的数值模拟方法和表征方法，能够在比目前可能的基础上更广泛地捕捉控制疲劳行为的耗散机制的相互作用。为了实现这一目标，现有的通用细观宏观建模平台将扩展到包括温度、加载速率和随时间变化的材料变化的影响，该平台通过局部累积应变演化来反映疲劳行为。理论和数值方面的发展将通过一个系统的实验计划来验证，该计划为所研究的现象提供了多个观察角度。为了最大限度地提高研究与工程实践的相关性，将使用先进的概率建模方法捕捉疲劳载荷和局部材料特性固有的随机性，这些方法将用于根据S-N曲线、疲劳裂纹扩展准则、加载顺序的影响和疲劳蠕变发展对疲劳行为进行统计表征。这一特征将作为工程规范中完善的设计和评估规则的基础。