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20 pages, 4352 KB

Open AccessArticle

Stochastic Optimization of Dissipation Structures Based on Lyapunov Differential Equations and the Full Stress Design Method

by Yunlong Zhang, Weizhi Xu, Dongsheng Du and Shuguang Wang

Buildings 2023, 13(3), 665; https://doi.org/10.3390/buildings13030665 - 2 Mar 2023

Cited by 3 | Viewed by 1719

Abstract

This article presents a Lyapunov precise integral-based analysis method for seismic structures with added viscous fluid dampers. This study uses the full stress algorithm as the optimization method, considering the mean square of interstory drifts as the optimization objective, the position of the damper as the optimization object, and the random vibration analysis method as the calculation method to optimize seismic frame structures with viscous dampers. A precise integral solution is derived for the Lyapunov equation based on the general expression of the Lyapunov differential equation for the damping system under the excitation of a nonstationary stochastic process using two types of modulation functions:

g (t) = 1

and

g (t) = \sqrt{t}

. Finally, the optimal damping arrangement is achieved using this method with a six-layer non-eccentric planar frame. In addition, the optimization results of this study are verified with those in the literature using time-history analysis, which verifies the feasibility and effectiveness of the proposed method. This study provides a method for the optimal configuration of dampers for seismic response of structures, which is beneficial for engineering applications and the protection of seismic structures. Full article

(This article belongs to the Special Issue Uncertainty Propagation of Complex Engineering Structures/Systems)

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21 pages, 12862 KB

Open AccessArticle

Energy Dissipation and Performance Assessment of the Connected Structure with a One-Side Damping Layer

by Liangkun Liu, Yuze Zheng, Zhaodong Pan and Qing Lyu

Buildings 2022, 12(9), 1438; https://doi.org/10.3390/buildings12091438 - 13 Sep 2022

Cited by 5 | Viewed by 3098

Abstract

Due to aesthetic demands and the necessity for multi-functionality, a unique structure with one or multiple links connecting adjacent buildings has attracted the attention of researchers. In order to improve vibration control, this study investigates the seismic mitigation performance of a connected structure with a one-side damping layer. The simplified shear model is employed to derive the structure’s motion equation. Based on the Kanai-Tajimi filtered spectrum model, the seismic response variances are calculated using the Lyapunov equation. To investigate the seismic energy distribution and mitigation performance, three models of the connected structure with a damping layer are analyzed using the index of the mean kinetic energy. The results shows that the stiffness and damping coefficient affects the vibration energy, while the excessive stiffness of the damping layer is shown to be detrimental to the damping effects. In sum, the novel connected structure shows excellent damping ability and effectively reduces the vibration energy. Damping layers placed at a lower position with a stiffer structure are shown to enhance the damping effect and lead to more energy dissipation through the damping layer. Thus, this study concludes that the introduction of a One-Side damping layer into the connected structure is an excellent alternative strategy for adjusting the energy distribution of the connected structure and meeting the design requirements. Full article

(This article belongs to the Special Issue New Trends in Seismic Performance Evaluation)

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14 pages, 3119 KB

Open AccessArticle

A Joint State-Parameter Identification Algorithm of a Structure with Non-Diagonal Mass Matrix Based on UKF with Unknown Mass

by Shiyu Wang and Ying Lei

Buildings 2022, 12(6), 826; https://doi.org/10.3390/buildings12060826 - 14 Jun 2022

Cited by 3 | Viewed by 2530

Abstract

Inaccurate mass estimates have been recognized as an important source of uncertainty in structural identification, especially for large-scale structures with old ages. Over the past decades, some identification algorithms for structural states and unknown parameters, including unknown mass, have been proposed by researchers. However, most of these identification algorithms are based on the simplified mechanical model of chain-like structures. For a chain-like structure, the mass matrix and its inverse matrix are diagonal matrices, which simplify the difficulty of identifying the structure with unknown mass. However, a structure with a non-diagonal mass matrix is not of such a simple characteristic. In this paper, an online joint state-parameter identification algorithm based on an Unscented Kalman filter (UKF) is proposed for a structure with a non-diagonal mass matrix under unknown mass using only partial acceleration measurements. The effectiveness of the proposed algorithm is verified by numerical examples of a beam excited by wide-band white noise excitation and a two-story one-span plane frame structure excited by filtered white noise excitation generated according to the Kanai–Tajimi power spectrum. The identification results show that the proposed algorithm can effectively identify the structural state, unknown stiffness, damping and mass parameters of the structures. Full article

(This article belongs to the Special Issue Structural Identification and Damage Evaluation by Integrating Physics-Based Models with Data)

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