U.S.-Czech Engineering Research on Softening Damage, Fracture and Size Effect in Concrete Structures Under Dynamic and Cyclic Loads

美捷工程研究动态和循环荷载下混凝土结构的软化损伤、断裂和尺寸效应

• 批准号: 9531299
• 负责人: Zdenek Bazant
• 金额: $ 3.94万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-09-01 至 2000-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9531299&HistoricalAwards=false
• 关键词: U.S.; Czech; Engineering; Research; Softening

INT 9531299 Bazant This U.S.-Czech research project between Zdenek Bazant of Northwestern University and three researchers from Czech Technical University, Zdenek Bittnar, Milan Jirasek and Jan Vitek, will focus on inelastic hinges in frames of buildings and bridges that undergo progressive damage and exhibit softening resulting from dynamic or cyclic loading such as that caused by earthquake, blast or impact. Such damage can remain distributed over many inelastic hinges or it can localize in only some of them. Dr. Bazant and his Czech partners note that localization is a dangerous phenomenon because it can cause collapse to occur more rapidly. This project will involve a systematic, theoretical and numerical study of the localization problem. The progressive degradation and fracture of concrete in compression under lateral confinement simulating the effect of reinforcement will also be studied, with analysis of localization and fracture extended to the shear failure of beams. Particular attention will be devoted to the size effect brought about by localization of softening and by fractures in tension, shear and compression. Results are expected to help make predictions of concrete structures' resistance to dynamic and cyclic loading more realistic and subsequently contribute to safer designs. This project in mechanics and materials engineering fulfills the program objective of advancing scientific knowledge by enabling experts in the United States and Eastern Europe to combine complementary talents and share research resources in areas of strong mutual interest and competence. ??

INT 9531299 Bazant 这个美国-西北大学的Zdenek Bazant和捷克技术大学的三名研究人员Zdenek Bittnar，Milan Jirasek和Jan Vitek之间的捷克研究项目将专注于建筑物和桥梁框架中的非弹性铰链，这些铰链经历渐进损坏并表现出因地震，爆炸或冲击等动态或循环荷载引起的软化。 这种损伤可以分布在多个非弹性铰链上，也可以局限于其中的一部分。 Bazant博士和他的捷克合作伙伴指出，局部化是一种危险的现象，因为它可能导致崩溃发生得更快。 这个项目将涉及一个系统的，理论和数值研究的本地化问题。 在横向约束条件下，混凝土在受压状态下的逐步退化和断裂也将被研究，模拟钢筋的作用，局部化和断裂的分析扩展到梁的剪切破坏。 将特别注意的尺寸效应所带来的局部软化和拉伸，剪切和压缩断裂。 研究结果将有助于预测混凝土结构对动态和循环荷载的抵抗力，从而有助于更安全的设计。 该机械和材料工程项目通过使美国和东欧的专家能够联合收割机互补人才并在共同感兴趣和能力强的领域共享研究资源，实现了推进科学知识的计划目标。 ??