Abstract
This article aims investigating the efficiency of the smart advanced control algorithm applied to the structural dynamic analysis with leaner quadratic regulator (LQR). We chose the linear-quadratic regulator algorithm to drive the system into the desired state, where the optimal control strategy considers minimization task of the cost-to-go functional with respect to the state error and control effort. Our main contribution in this paper is the development of a fast and scalable feasible solution for building nonlinear structural analysis. Thus, we seek to accommodate a time varying fuzzy model by LQR algorithm with the proposed smart modelling for design and analysis in systems. We provide a detailed theoretical formulation and its numerical implementation in a variational format form. Several illustrative numerical examples are provided to confirm an excellent performance of the proposed methodology. The objectives of this paper are access to adequate, safe and affordable housing and basic services, promotion of inclusive and sustainable urbanization and participation, implementation of sustainable and disasterresilient buildings, sustainable planning and management of human settlement. Therefore, the goal is believed to be achieved in the near future through the continuous development of AI and control theory for a better life from the environment and built systems.
Address
(1) Yahui Meng, ZY Chen, Ruei-Yuan Wang:
School of Science, Guangdong University of Petrochemical Technology, Maoming 525000, Peoples R. China;
(2) Timothy Chen:
Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125, USA.
Abstract
This study utilizes the superelasticity property of shape memory alloy (SMA) to form a shape memory alloy springbased tuned vibration absorber (SMA-TVA) for mitigating vibrations in multi-degree-of-freedom (MDOF) structures. Nitinol SMA is chosen for the fabrication of SMA specimens, and cyclic displacement loading tests are performed on both SMA wire and spring. Shaking table tests are then designed and executed on a three-story steel shear frame under tuned vibration absorber (TVA) and SMA-TVA control, respectively. Four seismic waves are selected to compare the performance of two dampers, with a specific focus on the time-frequency energy evolution of the MDOF structure under different excitations. Furthermore, the robustness of SMA-TVA is validated across varying excitation amplitudes and frequency ratios. Results reveal that SMA-TVA effectively attenuates vibrations beyond its tuning frequency, dissipating energy associated with multiple modes. It outperforms TVA with a significant 109.3% and 85.2% improvement in RMS displacement and acceleration reduction, respectively, with strokes reduced by up to 42.5% under earthquakes. Certain earthquakes exhibit a prolonged period of high energy input, facilitating more efficient and stable attenuation of vibrations for SMA-TVA. The average change in the vibration reduction ratio remains below 13.7% within the considered varying frequency ratios, indicating that SMA-TVA exhibits robustness against tuning frequency deviation.
Address
(1) Kunjie Rong, Zhengquan Cheng, Mengyao Zhou:
School of Civil Engineering, Shandong University, Jinan, Shandong Province, 250061, China;
(2) Mengyao Zhou, Weiyuan Huang:
Department of Disaster Mitigation for Structures, Tongji University, Shanghai, 200092, China;
(3) Ruisheng Ma:
Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education, Beijing University of Technology, Beijing, 100124, China;
(4) Na Li:
College of Civil Engineering, Qilu Institute of Technology, Jinan, Shandong Province, 250200, China.
Abstract
The application of piezoelectric patches for semi-active response control of steel special moment-resisting frames (SMRF) subjected to seismic excitations is investigated. Pairs of piezoelectric sheets bonded on the opposite faces of beams and columns are used to apply the required control couples through electric field-induced tensional or compressional strains in the piezoelectric sheets. Also, the modified Bang-Bang control algorithm as a typical control scheme is employed to determine the magnitude of the required control couples. For this purpose, Sap2000 software is utilized for modelling and time history analysis of the considered structural systems, and the MATLAB program is used to calculate the control couples. Furthermore, the open application programming interface (OAPI) codes are prepared for linking the Sap2000 and MATLAB software for online time history analysis of the structural models. The obtained results for a number of steel SMRFs with different numbers of bays and stories indicate that the application of the piezoelectric patches efficiently reduces the structural responses, including story drifts and story absolute accelerations. Also, using a design parameter, "λ", the best placement of the piezoelectric patches for the structural models is determined, and the responses of the optimally controlled cases are compared with those for the uncontrolled ones.
Key Words
optimal placement; piezoelectric patches; semi-active control; Special Moment Resisting Frame (SMRF); time history analysis
Address
(1) Fayaz R. Rofooei, Soroush Mosayyebi:
Department of Civil Engineering, Sharif University of Technology, 11155-4313 Tehran, Iran;
(2) Ali Nikkhoo:
Department of Civil Engineering, University of Science and Culture, Tehran, Iran.
Abstract
Rotational inertial mechanisms (RIMs) are promising for structural control as their mass amplification properties allow them to impart large mass effects. While most research on RIMs involves the linear inerter, there is interest in utilizing the variable mass effects from nonlinear RIMs (NRIMs). One type of NRIM is the variable inertia rotational mechanism (VIRM), which features moving masses in the device's flywheel that alter the flywheel's rotational inertia. While active and semi-active forms of the VIRM were previously considered, few studies have considered the passive VIRM. Consequently, the effect of VIRM parameters, the VIRM's capacity for shifting natural frequencies, and the performance of the VIRM under various loading types remain uncertain. This paper investigates the VIRM when attached to a single-degree-of-freedom primary structure. A mathematical model is derived for the combined primary structure and VIRM. Numerical simulations are carried out to determine the effect of the VIRM on the system's natural frequencies and dynamic response. This study demonstrates that the VIRM can significantly shift the primary structure's instantaneous and pseudo-natural frequencies, add higher frequency dynamics, and reduce the response of the structure in many cases, but that the impact of the VIRM is highly dependent on load type and amplitude.
Key Words
inerter; natural frequency; nonlinear; variable inertia rotational mechanism
Address
(1) Anika T. Sarkar:
Department of Civil and Environmental Engineering, The University of New Orleans, 2000 Lakeshore Drive New Orleans, LA 70148, USA;
(2) Nicholas E. Wierschem:
Department of Civil and Environmental Engineering, The University of Tennessee, 325 John D. Tickle Engineering Building, 851 Neyland Drive, Knoxville TN 37996-2313, USA.
