CAREER: Advanced Acceleration Control Methods and Substructure Techniques for Shaking Table Tests

这个教师早期职业发展（CAREER）计划项目的研究目标是开发提高结构振动台测试的准确性和能力的方法。特别是，本研究的目的是改善加速度控制方法，再现参考加速度在振动台和开发子结构技术，以考虑动态变化的边界条件。参考加速度的准确再现对于研究其对结构的真实影响至关重要。通过前馈和反馈控制相结合，创新，高性能的加速控制方法将通过分析和计算研究开发。这些加速度控制方法将根据各种条件下的多个稳定性和性能标准进行实验验证。将特别注意加速度轨迹跟踪性能。当部分结构模型在振动台上进行试验时，考虑与边界构件相互作用的子结构技术对于系统级评估是必不可少的。振动台的子结构技术将使用两种方法进行探索：1）惯性力方法，其中控制附加惯性质量的加速度以产生与边界力相等的惯性力，以及2）直接力方法，其中动态边界力由动态致动器直接施加。还将开发子结构技术所需的数值积分算法。将通过数值和实验研究来研究下部结构振动台试验的能力和局限性。 本文的研究成果将对地震工程产生直接影响，为结构在动荷载和边界条件下的抗震性能评估提供准确的试验手段。这项研究也与美国国家科学基金会的范围相吻合，乔治E。布朗一行地震工程模拟网络。该项目将为各级学生提供综合教育和研究机会。在K-12学生和公众的活动中，重点将放在通过动手实验室经验将他们的知识和项目联系起来。具体目标包括参加约翰霍普金斯大学妇女科学和工程方案和巴尔的摩理工高中实习方案的高中生。在大学一级，这项研究将被整合到一个实验室的本科动力学课程，PI目前提供。它还将提供本科研究机会，帮助学生发展动力学和控制理论的基本理解。在研究生阶段，一门新的课程，“结构的高级实验方法”，将把该项目纳入课程讲座和实验室活动。这项研究将通过项目网站传播，研究结果将通过一些重要期刊和会议记录发表。

The research objective of this Faculty Early Career Development (CAREER) program project is to develop methodologies that enhance accuracy and capabilities of shake table testing of structures. In particular, this study aims to improve acceleration control methods to reproduce reference accelerations at shake table and to develop substructure techniques to account for dynamically varying boundary conditions. The accurate reproduction of reference accelerations is critical for the investigation of their true impact on structures. By combining feed-forward and feedback control, innovative, high-performance acceleration control methods will be developed through analytical and computational studies. These acceleration control methods will be experimentally validated based on multiple stability and performance criteria under various conditions. Special attention will be paid to acceleration trajectory tracking performance. When partial structural models are tested on a shake table, substructure techniques that take into account interactions with boundary members are essential for the systems level assessment. Substructure techniques for shake tables will be explored using two approaches: 1) inertial force approach, where the acceleration of a supplemental inertial mass is controlled to generate an inertial force that is equivalent to the boundary force, and 2) direct force approach, where the dynamic boundary force is directly imposed by dynamic actuators. Numerical integration algorithms that are required for the substructure techniques will also be developed. Capabilities and limitations of the substructure shake table tests will be investigated through numerical and experimental studies. The results of this research will have a direct impact on earthquake engineering, by providing accurate experimental means for seismic performance assessment of structures under dynamic loadings and boundary conditions. This research also meshes well with the scope of the National Science Foundation, George E. Brown Jr. Network for Earthquake Engineering Simulation program. The project will provide integrated education and research opportunities for students at all-levels. In activities for K-12 students and the general public, the focus will be placed on linking their knowledge and the project through hands-on laboratory experience. Specific targets include high-school students in the Woman In Science and Engineering Program at the Johns Hopkins University and the Practicum Program at Baltimore Polytechnic High School. At the college level, this research will be integrated into a laboratory for the undergraduate Dynamics course that the PI is currently offering. It will also provide undergraduate research opportunities that help students develop fundamental understanding of theories in dynamics and control. At the graduate level, a new course, "Advanced Experimental Methods for Structures", will integrate the project into the course lecture and laboratory activities. This research will be disseminated through the project website, and the results will be published through a number of significant journals and conference proceedings.