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

该学院早期职业发展(CALEAR)项目的研究目标是开发方法，以提高结构振动台测试的准确性和能力。特别是，这项研究的目的是改进加速度控制方法，以在振动台上再现参考加速度，并发展子结构技术来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它们对结构的真实影响至关重要。通过将前馈控制和反馈控制相结合，通过分析和计算研究，将开发出创新的、高性能的加速度控制方法。这些加速度控制方法将在不同条件下基于多种稳定性和性能标准进行实验验证。将特别关注加速轨迹跟踪性能。当在振动台上测试部分结构模型时，考虑与边界成员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采用两种方法：1)惯性力法，即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；2)直接力法，其中动态边界力由动力执行器直接施加。还将开发子结构技术所需的数值积分算法。将通过数值和试验研究来研究子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的影响，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实验手段。这项研究也与国家科学基金会小乔治·E·布朗的研究范围很好地吻合。地震工程模拟网络程序。该项目将为各级学生提供一体化的教育和研究机会。在为K-12学生和普通公众举办的活动中，重点将放在通过动手实验室经验将他们的知识与项目联系起来。具体目标包括约翰·霍普金斯大学女性科学与工程项目和巴尔的摩理工学院高中实习项目的高中生。在大学层面，这项研究将被整合到国际工程学院目前提供的本科动力学课程的实验室中。它还将为本科生提供研究机会，帮助学生发展对动力学和控制理论的基本理解。在研究生阶段，一门名为“结构的高级实验方法”的新课程将把该项目纳入课程讲课和实验活动中。这项研究将通过项目网站传播，其结果将通过一些重要的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.