Collaborative Research: Simulating Crack Propagation in Steel Structures Under Ultra-Low Cycle Fatigue and Low-Triaxiality Loading from Earthquakes and Other Hazards

合作研究：模拟地震和其他灾害造成的超低周疲劳和低三轴度载荷下钢结构的裂纹扩展

基本信息

批准号：
1634291
负责人：
Amit Kanvinde
金额：
$ 25万
依托单位：
University of California-Davis
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2016
资助国家：
美国
起止时间：
2016-10-01 至 2021-09-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1634291&HistoricalAwards=false
关键词：
Collaborative Research Simulating Crack Propagation

项目摘要

Buildings, tunnels, utility pipelines, and other structures constructed of steel are critical components of the nation's civil infrastructure. As experienced during previous disasters, such as in the 1994 Northridge, California earthquake, steel structures are vulnerable to collapse or failure, resulting in loss of life and property. Cracking (i.e., fracture) in critical parts of these structures is often the reason for their failure. Consequently, designing structures to minimize the risk of fracture is critical for infrastructure safety and operability. However, methods to predict the growth of cracks are not well-developed, especially when fractures occur during severe shaking caused by earthquakes or other extreme loads. By combining expertise from structural engineering, materials science, and computational mechanics, the objectives of this research are to: (1) create new models and computational technologies to accurately simulate this type of cracking, and (2) integrate these models into the design process for civil infrastructure. Undergraduate and graduate students will actively participate in this research. The new knowledge, models, and software products from this research, through transfer to practitioners, will improve the safety and economy of buildings and other civil infrastructure, benefiting the U.S. society and economy. Nonlinear analysis is an essential technology for the modern performance-based design and construction of buildings and civil infrastructure that are more resilient to earthquakes and other extreme hazards. This research addresses a significant limitation of nonlinear analysis as it pertains to simulating crack propagation in steel structures, under two important situations: (1) ultra-low cycle fatigue (ULCF) loading, which is characterized by few (20) cycles of large strain amplitude that can occur under earthquakes and other hazards, and (2) low-stress triaxiality, which often occurs with ULCF loading in shear bands or at protruding corners of structural elements. This research will address these challenges through fundamental theoretical model development (a new damage mechanics based constitutive model for ULCF and low-triaxiality), computational methods synthesis, numerical implementation, laboratory testing, and calibration and validation of model implementations. The work will combine models for ductile crack initiation with computational techniques, resulting in validated approaches for simulating crack propagation under ULCF and low-triaxiality. The project will culminate in a campaign to facilitate adoption of the fracture simulation techniques into engineering research and practice, including standardization of simulation and calibration methods required for their realization, and development of open source software. These research products and their adoption into engineering practice will enhance safety and performance of the built environment.

建筑物，隧道，公用事业管道和其他由钢建造的结构是国家民用基础设施的关键组成部分。正如先前灾难中经历的那样，例如在1994年的加利福尼亚地震中，钢结构很容易崩溃或失败，从而导致生命和财产损失。这些结构的关键部分的破裂（即骨折）通常是它们失败的原因。因此，设计结构以最大程度地降低断裂风险对于基础设施的安全性和可操作性至关重要。但是，预测裂缝生长的方法并没有得到充分发达，尤其是在地震或其他极端负荷引起的严重摇动期间发生断裂时。通过结合结构工程，材料科学和计算机制的专业知识，这项研究的目标是：（1）创建新的模型和计算技术以准确模拟这种类型的破解，（2）将这些模型集成到设计过程中用于民用基础设施。本科生和研究生将积极参与这项研究。这项研究的新知识，模型和软件产品通过转移到从业人员将改善建筑物和其他民用基础设施的安全和经济，从而使美国社会和经济受益。非线性分析是基于现代绩效设计和建筑物和民用基础设施的现代设计和建造的必不可少的技术，这些技术对地震和其他极端危害更具弹性。这项研究解决了非线性分析的重要局限在地震和其他危害下可能发生的振幅，以及（2）低压力三轴性，通常是在剪切带中的ULCF载荷或结构元素的突出拐角处发生。这项研究将通过基本理论模型开发（基于新的损害力学的ULCF和低特分型构成模型），计算方法综合，数值实施，实验室测试以及模型实现的校准和验证。这项工作将将延性裂纹启动的模型与计算技术相结合，从而导致了经过验证的方法，用于模拟ULCF和低三副性下的裂纹传播。该项目将在一项运动中达到最终促进，以促进裂缝仿真技术进入工程研究和实践，包括模拟和校准方法的标准化以及开源软件的开发。这些研究产品及其在工程实践中的采用将增强建筑环境的安全性和性能。