Bio: Ping Tan is an academic researcher from Guangzhou University. The author has contributed to research in topics: Damper & Bearing (mechanical). The author has an hindex of 9, co-authored 50 publications receiving 417 citations.
TL;DR: In this article, a 3D finite-element model is developed in MATLAB to represent the complex behavior of the full-scale highway over-crossing and the nonlinear behavior of center columns and isolation bearings is considered in formulating the bilinear force-deformation relationship.
Abstract: This paper presents the problem definition of the benchmark structural control problem for the seismically excited highway bridge. The benchmark problem is based on the newly constructed 91/5 highway over-crossing in southern California. The goal of this benchmark effort is to develop a standardized model of a highway bridge using which competing control strategies, including devices, algorithms and sensors, can be evaluated comparatively. To achieve this goal, a 3D finite-element model is developed in MATLAB to represent the complex behavior of the full-scale highway over-crossing. The nonlinear behavior of center columns and isolation bearings is considered in formulating the bilinear force–deformation relationship. The effect of soil–structure interaction is considered by modeling the interaction by equivalent spring and dashpot. The ground motions are considered to be applied simultaneously in two directions. A MATLAB-based nonlinear structural analysis tool has been developed and made available for nonlinear dynamic analysis. Control devices are assumed to be installed between the deck and the end abutments of the bridge. Evaluation criteria and control constraints are specified for the design of controllers. Passive, semi-active and active devices and algorithms can be used to study the benchmark model. The participants in this benchmark study are required to define their control devices, sensors and control algorithms, evaluate and report the results of their proposed control strategies. Copyright © 2009 John Wiley & Sons, Ltd.
TL;DR: In this paper, three types of sample control systems, namely nonlinear viscous dampers, ideal hydraulic actuators and magnetorheological fluid dampers are designed and presented for comparison by participants in the study.
Abstract: This paper presents sample control system designs for the three-dimensional benchmark structural control problem for seismically excited highway bridge. Three types of sample control systems, namely nonlinear viscous dampers, ideal hydraulic actuators and magnetorheological fluid dampers, are designed and presented for comparison by participants in the study. For each of the three-sample control systems, a total of 16 control devices are proposed to be placed orthogonally between the deck-ends and abutments for the reduction of earthquake-induced vibrations of the highway bridge. An H2/LQG control algorithm is selected for the active case and a clipped optimal control algorithm is chosen for the semi-active case. To facilitate the controller design, an eigenmode reduction method is used to reduce the number of degrees of freedom of the initially elastic model to obtain a reduced-order model. However, the evaluation model to simulate the performance of control strategies is the full-order nonlinear finite element model. A Kalman filter is used to estimate states of the reduced-order model required for the applications of controllers for both active and semi-active cases using selected acceleration and displacement measurements. The modeling and sample control system designs presented in this paper are for illustration purposes only, and are not intended to be competitive. Participants of this benchmark study are expected to employ more competitive control designs for their own control strategies. These control strategies may be passive, active, semi-active or a combination thereof. Copyright © 2009 John Wiley & Sons, Ltd.
TL;DR: In this paper, the authors present the fully base-isolated highway bridge and sample Lyapunov semiactive controller (Part III) for a set of strong near-field earthquakes.
Abstract: SUMMARY This paper presents the fully base-isolated highway bridge benchmark problem. The highway bridge benchmark problem consists of two phases: (1) Phase I—the bridge deck being base isolated only at the abutments and the center bent being integral with the pier (without isolation), and (2) Phase II—the bridge deck being fully base isolated at both the bent/pier and abutment locations. In both phases of the highway bridge benchmark, the objective is to augment the performance of the isolation system using supplemental control strategies. The problem definition (Part I) as well as a sample controller (Part II) for Phase I of the study has been presented in the companion papers. The focus of this paper is to present the fully baseisolated highway bridge and sample Lyapunov semiactive controller (Part III). As-built structural designs of the 91/5 overcrossing in Orange county in Southern California are used to develop the finite-element model for this benchmark based on Phase I. The nonlinear analysis tool and the controller interface have been developed in MATLAB. The bridge is isolated using nonlinear elastomeric bearings with a lead core. Magneto-rheological (MR) dampers are used to control the seismic response of the bridge. The MR dampers are installed at the isolation level at 10 locations over the abutments and bent/pier locations, each location consisting of an orthogonal pair of dampers to control the responses in both directions. The outputs allowed in the benchmark problem definition are used to design the controller and the velocity and displacement measurements if required are obtained by integrating accelerations using a filter, which simulates integration. Detailed comparisons of benchmark performance indices for the fully base-isolated bridge with sample semiactive controllers and passive strategies are performed in comparison with the uncontrolled case, for a set of strong near-field earthquakes. The sample Lyapunov semiactive controller is shown to reduce the isolator and mid-span displacements. The modeling and sample control designs demonstrated in this paper can be used to form the basis for studying a wider variety of active and
TL;DR: In this paper, the authors proposed complex rotational stiffness for modeling multiple damped outriggers in a tall building, which considers the interaction between peripheral columns and the dampers in DBRs.
Abstract: This study proposes complex rotational stiffness for modeling multiple damped outriggers in a tall building. The complex rotational stiffness considers interaction between peripheral columns and the dampers in damped outriggers. By combining the complex rotational stiffness into a dynamic stiffness matrix, the dynamic characteristics of a building with multiple outriggers can be derived in accordance to the Benoulli–Euler beam theory. These dynamic characteristics subsequently provide a guideline for designing outriggers in a building. In this study, the proposed method is verified in comparison with a finite element model. An in-depth parametric study is then conducted by the proposed method to evaluate a building with outriggers with respect to the stiffness ratio of the core to perimeter columns, position of damped outriggers, and damping coefficient of linearly viscous dampers. The investigation shows that the modal damping is significantly influenced by the ratio of core-to-column stiffness, as well as is more sensitive to the damping coefficient of dampers than to the position of damped outriggers. All of the results obtained are non-dimensional and convenient for analysis and applications of designing damped outrigger systems.
01 Jan 1971
TL;DR: In this article, the authors deal with the dynamic ASPECTS of the sub-subject: MATHEMATICAL ANALYSIS of systems SUBJECTED to INDEPENDENT VIBRATIONS by means of MATHEATICAL MODELS.
Abstract: PART 1 DEALS WITH THE DYNAMIC ASPECTS OF THE SUBJECT: MATHEMATICAL ANALYSIS OF SYSTEMS SUBJECTED TO INDEPENDENT VIBRATIONS BY MEANS OF MATHEMATICAL MODELS. THE ANALYTICAL SYSTEMS USED ARE NON-LINEAR SYSTEMS, HYDRODYNAMICS AND NUMERICAL METHODS. PART 2 EXAMINES SEISMIC MOVEMENTS, THE DYNAMIC BEHAVIOUR OF STRUCTURES AND THE BASIC CONCEPTS OF THE SEISMIC DESIGN OF STRUCTURES.
01 Jan 1980
TL;DR: In this paper, a formal written transfer of copyright from the Author(s) to the Journal is required for each manuscript, which ensures that the manuscript is first published in the Journal and that the Journal retains the right to provide for the widest possible dissemination of the manuscript through first publication, reprints and translations, in all formats and media, including print, electronic and/or web based media.
Abstract: Formal written transfer of copyright from the Author(s) to the Journal is required for each manuscript. Such transfer ensures that the manuscript is first published in the Journal. The Journal retains the right to provide for the widest possible dissemination of the manuscript through first publication, reprints, and translations, in all formats and media, including print, electronic and/or web based media. Without this transfer of copyright, such activities on the part of the Journal and the corresponding dissemination of information are limited; transfer of copyright is also required to enable the Journal to defend against plagiarism and other forms of copyright infringement. We therefore ask that you complete and return this form promptly. Your cooperation is essential and appreciated.
TL;DR: In this paper, a period from the second semester of 2009 to the first semester of 2011 is analyzed in terms of theoretical, numerical and experimental studies, as well as the use of control algorithms and devices in actual implementations.
Abstract: It is internationally recognized that structural control was introduced in civil engineering through a pioneering article by Yao and through the implementations promoted by Kobori. The concepts of active and semi-active structural control in civil and infrastructure engineering date back 40 years and much progress has been recorded during these four decades. Periodically, state-of-the-art manuscripts have been published and technical books were also printed to testify the maturation of the topic. This article only covers the period from the second semester of 2009 to the first semester of 2011, emphasizing the developments in terms of theoretical, numerical and experimental studies, as well as the use of control algorithms and devices in actual implementations. It is observed that there are still several operational limitations to prevent from the expected growth of the applications in standard design. Nevertheless, some innovative concepts help to foresee future developments within special sectors of app...
TL;DR: A comprehensive review of state-of-the-art researches on NESs, highlighting possible complex dynamics resulting in a NES coupled to a structure and suggesting further promising directions, such as NESs for multidirectional vibration reduction, NESs with nonlinearities beyond the cubic, and potential deterioration caused by a NES.
Abstract: Nonlinear energy sink (NES) is an appropriately designed nonlinear oscillator without positive linear stiffness. NES can suppress vibrations over a wide frequency range due to its targeted energy transfer characteristics. Thus, investigations on NES have attracted a lot of attention since a NES was proposed. Designs, analysis, and applications of NESs are still active since different configurations are needed in various practical circumstances. The present work provides a comprehensive review of state-of-the-art researches on NESs. The work begins with a survey of the generation of a NES and its important vibration control characteristics. The work highlights possible complex dynamics resulting in a NES coupled to a structure. The work also summarizes some significant design on the implements of optimal damping effects and the offsets of NES shortcomings. Then, the work details the applications of NESs in all engineering fields. The concluding remarks suggest further promising directions, such as NESs for multidirectional vibration reduction, NESs with nonlinearities beyond the cubic, potential deterioration caused by a NES, low-cost NESs, NESs for extremely low frequency range, and NESs integrated into active vibration controls. There are 383 references in the review, including some publications of the authors.
TL;DR: The first phase of the seismic excited base-isolated benchmark building was received well by the structural control community, culminating in the March 2006 journal special issue as mentioned in this paper, which contained contributions from over dozen participants world-wide.
Abstract: SUMMARY The first phase of the seismically excited base-isolated benchmark building was received well by the structural control community, culminating in the March 2006 journal special issue. The special issue contained contributions from over dozen participants world-wide. While the focus of the Phase I effort was on linear isolation systems, Phase II attempts to galvanize research efforts on control of base-isolated buildings with nonlinear isolation systems. Primarily, friction and hysteretic lead–rubber-bearing (LRB) isolation systems are included in this effort. The superstructure and the control framework remains the same as the Phase I benchmark. The main difference will be in the nonlinear isolation systems used, and consequently the controllers necessary to control such systems. The primary objective of this paper is to present the Phase II benchmark problem definition along with a sample controller for friction isolation system. A sample controller for the LRB isolation system was presented earlier as a part of the Phase I special issue. Included in this paper is a broad set of carefully chosen performance measures, which remain the same as Phase I, so that the participants may evaluate their respective control designs. The control algorithms may be passive, active or semiactive. The benchmark structure considered in the Phase II study is an eight-story base-isolated building that is identical to the one considered for the Phase I study. The base isolation system consists of a combination of linear, nonlinear bearings and control devices. The superstructure is considered to be a linear elastic system with lateral–torsional behavior. The nonlinearities due to the isolators and control devices are limited to the isolation level only. A nonlinear dynamic analysis program and sample controllers are made available to the participants to facilitate direct comparison of results of different control algorithms. Copyright r 2008 John Wiley & Sons, Ltd.