CAREER: Protecting Buildings and Structures from Vibration Damage using Variable Inertance Mechanisms

这项学院早期职业发展(Career)补助金将通过研究利用可变惯性机制的方法，促进对被动控制策略的理解，以保护结构免受暴风雨和地震等自然灾害造成的振动破坏。变惯性机构是一种将一种能量(在这种情况下是振动)转移到另一种(在这种情况下是旋转)的非线性装置。其结果是增加了质量效应，可变地改变了系统频率，通过破坏结构和施加的动态载荷之间的有害相互作用来保护结构。这种保护机制与目前最先进的被动结构控制方法有很大不同，这些被动结构控制方法寻求通过精确调整的装置来减轻损害，或者通过设计用于吸收损害的阻尼器或装置来耗散能量。该项目将实现新的基于可变惯性的设计，允许建造更安全和更经济的建筑，从而促进公共福利和繁荣。这项研究将作为实践课程整合到本科生和研究生课程中，以激发人们对结构工程的兴趣并推进培训。此外，外展活动将通过促进社区大学学生向四年制工程项目的过渡，帮助缩小工程专业学生培训方面的关键差距。来自该奖项的数据将被存档并在自然灾害工程研究基础设施(NHERI)数据仓库(https://www.DesignSafe-ci.org).)中公开可用该奖项支持国家科学基金会在国家减少地震灾害计划(NEHRP)和国家减少风暴影响计划(NWIRP)中的作用。旋转惯性机制的特点是将平移运动转换为飞轮的旋转运动，可以产生大的有效质量，即惯性，而物理质量较小。本项目将评估这样一种假设，即通过可变惯性转动惯量装置获得的有效质量的变化可以用来保护结构免受动态载荷的影响。结构中的可变惯性将通过状态切换机构来考虑，在状态切换机构中，转动机构被动地与结构和功能可变的惯性机构啮合和脱离，在该机构中，惯性作为机构响应的函数被动地变化。这项研究将包括分析建模、数值模拟和实验测试。具体的智力贡献将包括：1)确定可用于制造可变惯性装置的状态切换和功能可变的惯性机制，2)描述可变惯性策略对自然频率的影响，3)评估和表征可变惯性策略的结构控制有效性，以及4)评估实际建筑结构中可变惯性策略的有效性。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

This Faculty Early Career Development (CAREER) grant will advance understanding of passive control strategies for structural protection from vibration damage due to natural hazards, such as windstorms and earthquakes, by investigating methodologies that utilize variable inertance mechanisms. Variable inertance mechanisms are nonlinear devices that transfer one kind of energy (in this case vibration) to another (in this case rotation). The result is an added mass effect that variably changes the system frequencies, which protects the structure by disrupting harmful interactions between the structure and applied dynamic loads. This mechanism of protection differs significantly from current state-of-the-art passive structural control methods that seek to mitigate damage with precisely tuned devices or dissipate energy through dampers or devices designed to absorb damage. This project will enable new variable inertance-based designs that allow for safer and more economically constructed buildings, thus advancing public welfare and prosperity. The research will be integrated as hands-on curriculum into undergraduate and graduate courses to stimulate interest and advance training in structural engineering. Additionally, outreach activities will help close a critical gap in the training of engineering students by promoting the transition of community college students to four-year engineering programs. Data from this award will be archived and made publicly available in the Natural Hazards Engineering Research Infrastructure (NHERI) Data Depot (https://www.DesignSafe-ci.org). This award supports the National Science Foundation role in the National Earthquake Hazards Reduction Program (NEHRP) and the National Windstorm Impact Reduction Program (NWIRP).Rotational inertial mechanisms feature the transformation of the translational motion to the rotational motion of a flywheel and can produce large effective mass, known as inertance, with small physical mass. This project will evaluate the hypothesis that variations in effective mass achieved by variable inertance rotational inertia devices can be used to protect structures from dynamic loads. Variable inertance in structures will be considered through state-switching mechanisms in which the rotational mechanism passively engages and disengages with a structure and functionally varied inertance mechanisms in which the inertance passively varies as a function of the response of the mechanism. This research will include analytical modeling, numerical simulations, and experimental testing. Specific intellectual contributions will include: 1) determination of state-switching and functionally varied inertance mechanisms that can be used to produce variable inertance devices, 2) characterization of the effect on natural frequencies of variable inertance strategies, 3) evaluation and characterization of the structural control effectiveness of variable inertance strategies, and 4) assessment of effectiveness of variable inertance strategies in realistic building structures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.