scholarly journals Theoretical Study on a Cable-Bracing Inerter System for Seismic Mitigation

2019 ◽  
Vol 9 (19) ◽  
pp. 4096 ◽  
Author(s):  
Liyu Xie ◽  
Xinlei Ban ◽  
Songtao Xue ◽  
Kohju Ikago ◽  
Jianfei Kang ◽  
...  
Keyword(s):  
Design Method ◽  
Damping Ratio ◽  
Control Level ◽  
Structural Response ◽  
Optimization Method ◽  
Force Output ◽  
Earthquake Excitation ◽  
Single Degree Of Freedom ◽  
Dynamic Motion ◽  
Optimal Design Method

In this paper, cables are proposed to connect the inerter and main frame for translation-to-rotation conversion, i.e., the cable-bracing inerter system (CBIS), with a magnified mass and enhanced damping effect. This novel configuration has the benefits of deformation relaxation at the connecting joints, easy installation, and an adaptive layout for nonconsecutive-story deployment. Dynamic motion equations were established for a single degree-of-freedom (SDOF) model equipped with a CBIS. The influence of dimensionless parameters, such as inertance-mass ratio, stiffness ratio and additional damping ratio on vibration mitigation were studied in terms of displacement response and force output. A single objective and multiple objective optimal design method were developed for a CBIS-equipped structure based on a performance-oriented design framework. Finally, the mitigation effect was illustrated and verified by a numerical simulation in a time-domain. The results showed that a CBIS is an effective structural response mitigation device used to mitigate the response of structural systems under earthquake excitation. Using the proposed optimization method, CBIS parameters can be effectively designed to satisfy the target vibration control level.

scholarly journals Coupled Dynamic Analysis and Decoupling Optimization Method of the Laser Gyro Inertial Measurement Unit

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 111
Author(s):  
Fang Fang ◽  
Wenhui Zeng ◽  
Zilong Li
Keyword(s):  
Frequency Response ◽  
Vibration Frequency ◽  
Inertial Measurement Unit ◽  
Design Method ◽  
Optimization Method ◽  
Measurement Unit ◽  
Coupled Vibration ◽  
Inertial Measurement ◽  
Laser Gyro ◽  
Optimal Design Method

The mechanical dithered ring laser gyro (RLG) effectively overcomes the lock-in effect and ensures the sensitive accuracy of the low angular rate for the gyro. However, in the inertial measurement unit (IMU) system, the dither excitation of three RLGs causes the coupled vibration of the IMU structure, which could seriously limit the measuring accuracy of RLGs. In this paper, the vibration frequency response characteristic of laser gyro IMU is taken as the focus point, and the method of multi-rigid body dynamics is used to establish the dynamic model of IMU suitable for vibration frequency response analysis. On the basis of the model, the multi-degree-of-freedom coupling vibration of IMU with the gyro dither excitation is clearly described. A new IMU dynamic decoupling optimization method is proposed to minimize the coupled vibration frequency response, and compared with the previous optimal design method. The prototype experimental test results show that the coupled vibration of IMU is restrained more effectively by the proposed new method than by the previous optimal design method. Finally, on the basis of this new method, the measuring accuracy of the RLGs in the IMU system is improved, which is quite useful for practical engineering application.

Optimal Design for Broadband Dynamic Damper

2012 ◽  
Vol 490-495 ◽  
pp. 2723-2727
Author(s):  
Yan Ting Ai ◽  
Jing Tian ◽  
Qi Fu ◽  
Feng Ling Zhang
Keyword(s):  
Genetic Algorithm ◽  
Optimal Design ◽  
Frequency Ratio ◽  
Design Method ◽  
Damping Ratio ◽  
Excitation Frequency ◽  
Linear Dynamic ◽  
Dynamic Absorber ◽  
Optimal Design Method ◽  
Definition Of

This paper presents a new optimal design method based on genetic algorithm（GA）for broadband linear dynamic absorber. A New definition of the suppression bandwidth is described firstly. Then the method and procedure to optimize multi-parameters of broadband dynamic absorber is proposed. Effects of the natural frequency ratio, excitation frequency ratio, mass ratio, main system damping ratio and absorber ratio on the suppression bandwidth are discussed systematically. Finally the merits of genetic algorithm used for broadband linear dynamic absorber design are illustrated by contrasting it to a numerical method.

An Optimal Design Method for Radar Brackets

2011 ◽  
Vol 328-330 ◽  
pp. 232-236
Author(s):  
Lian Zhong Guo ◽  
Ding Yang ◽  
Zi Teng Huang
Keyword(s):  
Optimal Design ◽  
Conceptual Design ◽  
Phased Array ◽  
Design Method ◽  
Optimization Method ◽  
Design Stage ◽  
Evolutionary Structural Optimization ◽  
Excessive Weight ◽  
Optimal Design Method ◽  
Implementation Method

The purpose of this work is to present an optimal design method for radar brackets to get the lightest structure with stiffness constraint. Current radar brackets usually have conservative strength and excessive weight which influences the mobility of radar greatly as they are not optimized in the conceptual design stage. In this paper the well-known ESO (Evolutionary Structural Optimization) method based on ANSYS is studied and used as the method to optimize them. To begin with the criteria of ESO method and its implementation method are studied. Then a case of optimization for a phased array radar bracket is studied and at last the optimization result is compared to the result by using WORKBENCH (a commercial CAE software) and the comparison shows that this method has its unique superiority.

Graphic Establishment of Crank-Rocker Mechanism Design Based on Optimum Transmission Angle of Optimization Method

2014 ◽  
Vol 945-949 ◽  
pp. 301-305
Author(s):  
Da Yu Huang ◽  
Xiao Lu Wang
Keyword(s):  
Optimal Design ◽  
Mechanism Design ◽  
Design Method ◽  
Practical Method ◽  
Optimization Method ◽  
Transmission Angle ◽  
Optimal Design Method

The paper provides a simple, fast and practical method which follows the rule of maximizing minimum transmission angle to design crank-rocker mechanism. The method which uses the optimal design method is based on the research of papers[1]~[3] . Through the analysis and calculation, the paper gives the conclusion and drawing of k-φ-d-(γmin) max and k-d-a-b.

scholarly journals On the Estimation of the Moving Mass of a TMD Installed on a Lively Structure

2021 ◽  
Vol 11 (10) ◽  
pp. 4712
Author(s):  
Alvaro Magdaleno ◽  
Cesar Pelaez ◽  
Alvaro Iglesias-Pordomingo ◽  
Antolin Lorenzana
Keyword(s):  
Natural Frequency ◽  
Damping Ratio ◽  
Structural Response ◽  
Degree Of Freedom ◽  
Moving Mass ◽  
Tuned Mass Dampers ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Modification Technique ◽  
One Step

Tuned Mass Dampers are devices which can be assimilated to single-degree-of-freedom systems with a certain amount of moving mass, a natural frequency and a damping ratio intended to be installed on lively structures to reduce the contribution of a certain mode to their response. Once placed on the structure, the movement of the mass damper couples to the structural response and determines its properties as an isolated system becomes challenging. The authors have previously presented a methodology to estimate the natural frequency and damping ratio of an SDOF system installed on a structure and not necessarily tuned to a certain mode. It was based on a transmissibility function and, thus, the moving mass could not be estimated. With this work, the authors go one step further and present a novel procedure to estimate the moving mass value by means of the same transmissibility function and two well selected frequency response functions. The methodology is applied to estimate the properties of a real single-degree-of-freedom system placed on a lively timber platform. The results are compared with the mass modification technique to show that the proposed methodology provides better estimations in a more efficient way.

scholarly journals Lightweight and maintainable rotary-wing UAV frame from configurable design to detailed design

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110349
Author(s):  
Huiqiang Guo ◽  
Mingzhe Li ◽  
Pengfei Sun ◽  
Changfeng Zhao ◽  
Wenjie Zuo ◽  
...  
Keyword(s):  
Design Method ◽  
Geometric Model ◽  
Optimization Method ◽  
Frame Structure ◽  
Manufacturing Cost ◽  
Detailed Design ◽  
High Manufacturing Cost ◽  
The Military ◽  
Rotary Wing ◽  
Novel Design

Rotary-wing unmanned aerial vehicles (UAVs) are widespread in both the military and civilian applications. However, there are still some problems for the UAV design such as the long design period, high manufacturing cost, and difficulty in maintenance. Therefore, this paper proposes a novel design method to obtain a lightweight and maintainable UAV frame from configurable design to detailed design. First, configurable design is implemented to determine the initial design domain of the UAV frame. Second, topology optimization method based on inertia relief theory is used to transform the initial geometric model into the UAV frame structure. Third, process design is considered to improve the manufacturability and maintainability of the UAV frame. Finally, dynamic drop test is used to validate the crashworthiness of the UAV frame. Therefore, a lightweight UAV frame structure composed of thin-walled parts can be obtained and the design period can be greatly reduced via the proposed method.

scholarly journals Surrogate-Based Optimization of Horizontal Axis Hydrokinetic Turbine Rotor Blades

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4045
Author(s):  
David Menéndez Arán ◽  
Ángel Menéndez
Keyword(s):  
Turbine Blade ◽  
Design Method ◽  
Optimization Method ◽  
Turbine Rotor ◽  
Computational Effort ◽  
Rotor Blades ◽  
Linear Functions ◽  
Cavitation Inception ◽  
Hydrokinetic Turbine ◽  
Blade Geometry

A design method was developed for automated, systematic design of hydrokinetic turbine rotor blades. The method coupled a Computational Fluid Dynamics (CFD) solver to estimate the power output of a given turbine with a surrogate-based constrained optimization method. This allowed the characterization of the design space while minimizing the number of analyzed blade geometries and the associated computational effort. An initial blade geometry developed using a lifting line optimization method was selected as the base geometry to generate a turbine blade family by multiplying a series of geometric parameters with corresponding linear functions. A performance database was constructed for the turbine blade family with the CFD solver and used to build the surrogate function. The linear functions were then incorporated into a constrained nonlinear optimization algorithm to solve for the blade geometry with the highest efficiency. A constraint on the minimum pressure on the blade could be set to prevent cavitation inception.

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