scholarly journals Robust Optimal Damper Placement of Nonlinear Oil Dampers With Uncertainty Using Critical Double Impulse

2021 ◽  
Vol 7 ◽  
Author(s):  
Kohei Fujita ◽  
Ryota Wataya ◽  
Izuru Takewaki
Keyword(s):  
Optimal Design ◽  
Structural Design ◽  
Structural Parameters ◽  
Ground Motions ◽  
Structural Safety ◽  
Structural Performance ◽  
Damping Force ◽  
Placement Problem ◽  
Earthquake Ground Motions ◽  
Robust Optimal Design

A new robust method for optimal damper placement is presented for building structures under the critical double impulse. Oil dampers are treated here as representative supplemental dampers to control the seismic response of high-rise buildings. Such oil dampers usually obey a bi-linear force-velocity relation in controlling the maximum damping force through a relief mechanism to avoid the occurrence of excessive design forces in surrounding frames. The influence of uncertainty in characteristics of those bi-linear oil dampers on building structural safety is investigated. For the efficient evaluation of dynamic performance, the resonant critical double impulse is used as the base input instead of actual earthquake ground motions. Since the critical double impulse is determined to maximize the input energy to the objective building by changing the second impulse timing, uncertainties in input ground motions can be taken into account in a robust manner. To consider these various uncertainties, the robustness function based on the Info-Gap model is used in the robust optimization to assess structural performance variations caused by various uncertainties in the structural design phase. In this paper, a new innovative objective function in the robust optimal damper placement problem is proposed to enhance the robustness of structural performance under the variation of structural parameters by comparing the robustness function of the robust design with that of an ordinary optimal damper placement without considering uncertainties. Numerical examples of the robust optimal design of linear and bi-linear oil damper placements are shown for 10-story and 20-story planar building frame models. Structural performances of the robust optimal design to the conventional design earthquake ground motions are examined to investigate the validity of using the critical double impulse in the structural design under uncertainties.

Structure Optimal Design of Pneumatic 6-DOF Parallel Robot Based on Natural Frequency

2010 ◽  
Vol 450 ◽  
pp. 349-352 ◽  
Author(s):  
Bo Wu ◽  
Li Xu ◽  
Xiao Dong Yu ◽  
Zhi Wei Wang ◽  
He Xu
Keyword(s):  
Mathematical Model ◽  
Optimal Design ◽  
Natural Frequency ◽  
Dynamic Equation ◽  
Structural Design ◽  
Optimization Design ◽  
Structural Parameters ◽  
Parallel Robot ◽  
Optimization Rule ◽  
Design Aspect

. In order to improve the dynamic response rapidity and positioning precision for pneumatic 6-DOF parallel robot from the structural design aspect, a mathematical model of natural frequency for the parallel robot is developed based on dynamic equation by using vibration theory. The influences of structural parameters on minimal natural frequency are analyzed by simulation and an optimization rule of structural parameters based on minimal natural frequency is proposed. The optimization rule has advantages of simplification and efficiency, which provides a new theoretical gist for optimization of structural parameters as well as for checking the results of the actual natural frequency for pneumatic 6-DOF parallel robot. And this new rule is also valuable for structural optimization design of other similar parallel robot.

scholarly journals Linear optimal design of a magnetic repulsion negative stiffness structure

2021 ◽  
pp. 146134842199261
Author(s):  
Zhang Bao ◽  
Wang Xiaoping ◽  
Ge Xinfang
Keyword(s):  
Optimal Design ◽  
Structural Design ◽  
Simulation Analysis ◽  
Structural Parameters ◽  
Negative Stiffness ◽  
Design Parameters ◽  
Structural Parameter ◽  
Design Requirements

To reduce negative stiffness structure’s stiffness non-linearity, enhance its stability during entire working displacement range, and expand its allowable working displacement, the optimal design of negative stiffness structure based on magnetic repulsion is proposed, and its structural parameters are also provided. The new negative stiffness structure’s model is established to determine the structural design parameters. According to the change of the new negative stiffness structure’s stiffness curve, we select the structural parameter to meet the design requirements. In order to verify the effectiveness of the proposed negative stiffness structure, we carried out simulation analysis, and the results show that the optimized negative stiffness structure’s stiffness non-linearity is greatly reduced in a relatively longer displacement, and its stiffness stability is promoted substantially compared with the simple triple-magnet negative stiffness structure.

Seismic Performance of RC Structures Using an Improved Inelastic Analysis Method

2006 ◽  
Vol 324-325 ◽  
pp. 1021-1026
Author(s):  
Jin Ho Kim ◽  
Sin Chu Yang
Keyword(s):  
Ground Motions ◽  
Earthquake Hazard ◽  
Structural Performance ◽  
Analysis Method ◽  
Diagram Method ◽  
Rc Structures ◽  
Earthquake Ground Motions ◽  
Inelastic Analysis ◽  
First Approximation ◽  
Hazard Level

Inelastic analysis procedures may be useful as a first approximation for the seismic response of a structure. The Capacity Diagram Method procedure, which is based on R--T (Reduction-ductility-Period) relationships, is investigated to compare with the modified CDM procedure. The CDM procedure is applied to the example model, which is moment resistant RC frame. Two seismic hazard categories having exceedance probabilities of 2% in 50 years and 10% in 50 years earthquake ground motions have been selected for evaluating the performance of the example model. The performance objective of the example model is represented by the combination of a structural performance level and an earthquake hazard level.

Structure-Specific Scalar Intensity Measures for Near-Source and Ordinary Earthquake Ground Motions

2007 ◽  
Vol 23 (2) ◽  
pp. 357-392 ◽  
Author(s):  
Nicolas Luco ◽  
C. Allin Cornell
Keyword(s):  
Ground Motions ◽  
Linear Regression Analysis ◽  
Structural Performance ◽  
Intensity Measures ◽  
Earthquake Ground Motions ◽  
Long Period ◽  
Earthquake Records ◽  
Dynamic Analyses ◽  
Nonlinear Dynamic Analyses ◽  
A Site

Introduced in this paper are several alternative ground-motion intensity measures ( IMs) that are intended for use in assessing the seismic performance of a structure at a site susceptible to near-source and/or ordinary ground motions. A comparison of such IMs is facilitated by defining the “efficiency” and “sufficiency” of an IM, both of which are criteria necessary for ensuring the accuracy of the structural performance assessment. The efficiency and sufficiency of each alternative IM, which are quantified via (i) nonlinear dynamic analyses of the structure under a suite of earthquake records and (ii) linear regression analysis, are demonstrated for the drift response of three different moderate- to long-period buildings subjected to suites of ordinary and of near-source earthquake records. One of the alternative IMs in particular is found to be relatively efficient and sufficient for the range of buildings considered and for both the near-source and ordinary ground motions.

scholarly journals Comprehensive Review of Optimal and Smart Design of Nonlinear Building Structures With and Without Passive Dampers Subjected to Earthquake Loading

2021 ◽  
Vol 7 ◽  
Author(s):  
Izuru Takewaki ◽  
Hiroki Akehashi
Keyword(s):  
Optimal Design ◽  
Ground Motions ◽  
Seismic Loading ◽  
Building Structures ◽  
Earthquake Loading ◽  
Comprehensive Review ◽  
Building Frames ◽  
Earthquake Ground Motions ◽  
Passive Dampers ◽  
Made In

The optimal and smart design of nonlinear building structures with and without passive dampers subjected to earthquake loading is of great concern in the structural design of building structures. The research started around 1980 and many investigations have been conducted. A comprehensive review on this subject is made in this article. After the description of essential features of the optimal design problem of nonlinear building structures under earthquake ground motions, analysis types of optimization problems are explained and the significance of the dynamic pushover analysis is discussed from the viewpoint of analysis of limit states under earthquake ground motions of magnitude larger than the code-specified level. Then, the categorization by the response of frames and dampers was made. In this categorization, several subjects are discussed first: 1) Optimal design of bare nonlinear building frames under seismic loading, 2) Optimal design of nonlinear dampers for elastic building frames under seismic loading, 3) Optimal design of linear dampers for nonlinear building frames under seismic loading, 4) Optimal design of nonlinear building frames with specified nonlinear dampers under seismic loading, 5) Optimal design of nonlinear dampers for specified nonlinear building frames under seismic loading, 6) Simultaneous optimization of elastic-plastic building structures and passive dampers. Finally, the classification of researches in view of solution strategies is conducted for providing another viewpoint.

Technical Analysis of Optimal Design for Building Structure Considering Cost Constraint of Project

2014 ◽  
Vol 496-500 ◽  
pp. 2563-2568
Author(s):  
Yan E Hao ◽  
Yong Qiang Lan
Keyword(s):  
Optimal Design ◽  
Structural Design ◽  
Architectural Design ◽  
Structural Engineering ◽  
Structural Safety ◽  
Building Structure ◽  
Cost Constraints ◽  
Current Design ◽  
Engineering Cost ◽  
Relationship Of

Cost of building structure takes a large proportion of total construction investment. Investors also come to realize that different structural designs affect project cost, which means the higher demand for structural design institutes, because it requires structural designers to work out safe, suitable, perdurable and economic structural design by either meeting current design codes, or considering structure cost constraints and architectural design scheme. One way of controlling the structural engineering cost is to optimize the structural design. This article analyzes the factors which affect the structural costs and optimal design methods, and it discusses the relationship of structural material quantity and structural safety. This article aims to provide reference and guidance for structural designer’s optimization.

scholarly journals A Comprehensive Study on the Optimal Design of Magnetorheological Dampers for Improved Damping Capacity and Dynamical Adjustability

Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 64
Author(s):  
Liankang Wei ◽  
Hongzhan Lv ◽  
Kehang Yang ◽  
Weiguang Ma ◽  
Junzheng Wang ◽  
...  
Keyword(s):  
Optimal Design ◽  
Optimization Methods ◽  
Design Stage ◽  
Damping Capacity ◽  
Damping Force ◽  
Simulation And Optimization ◽  
Damping Characteristics ◽  
Hysteretic Characteristics ◽  
Gap Width ◽  
Comprehensive Study

Purpose: We aim to provide a systematic methodology for the optimal design of MRD for improved damping capacity and dynamical adjustability in performing its damping function. Methods: A modified Bingham model is employed to model and simulate the MRD considering the MR fluid’s compressibility. The parameters that describe the structure of MRD and the property of the fluid are systematically examined for their contributions to the damping capacity and dynamically adjustability. A response surface method is employed to optimize the damping force and dynamically adjustable coefficient for a more practical setting related to the parameters. Results: The simulation system effectively shows the hysteretic characteristics of MRDs and shows our common sense understanding that the damping gap width and yoke diameter have significant effects on the damping characteristics of MRD. By taking a typical MRD device setup, optimal design shows an increase of the damping force by 33% and an increase of the dynamically adjustable coefficient by 17%. It is also shown that the methodology is applicable to other types of MDR devices. Conclusion: The compressibility of MR fluid is one of the main reasons for the hysteretic characteristics of MRD. The proposed simulation and optimization methods can effectively improve the MRD’s damping performance in the design stage.

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