Floor Vibration Control Using Three-Degree-of-Freedom Tuned Mass Dampers

2004 ◽  
Author(s):  
Khalid I. Al-Hulwah ◽  
Reza Kashani
Keyword(s):  
Building Materials ◽  
Low Cost ◽  
Heavy Traffic ◽  
High Strength ◽  
Degree Of Freedom ◽  
Tuned Mass Dampers ◽  
Floor Vibration ◽  
Normal Human ◽  
High Level ◽  
Three Degree Of Freedom

The use of high-strength material in buildings has resulted in the use of less building materials and, consequently, a high level of flexibility in buildings, making them vibration prone. For example, high-strength concrete has lowered the thickness of concrete slabs used in the floors of steel/concrete buildings, such as office buildings and shopping centers, resulting in excessive floor vibration stemming from heavy traffic and normal human activity. Although not dangerous, such vibration is highly annoying to the occupants of the building. The authors have been working on the use of three-degree-of-freedom (3-DOF) tuned mass dampers (TMD) to abate floor vibration. Such TMDs can provide improved effectiveness over a traditional one-degree-of-freedom TMD and yet possess all of the attractive features of a traditional TMD; namely, simplicity and low cost. As in a 1-DOF TMD, this device will be installed on a concrete floor slab, at an optimally designed/chosen location.

Design of a Teaching Robot with Three Degrees of Freedom

2012 ◽  
Vol 619 ◽  
pp. 325-328
Author(s):  
You Jun Huang ◽  
Ze Lun Li ◽  
Zhi Cheng Huang
Keyword(s):  
Degrees Of Freedom ◽  
Low Cost ◽  
Degree Of Freedom ◽  
Good Repeatability ◽  
Main Components ◽  
Opening And Closing ◽  
Three Degree Of Freedom ◽  
Three Degrees Of Freedom ◽  
Application Prospects

A teaching robot with three degree of freedom is designed. The three degrees of freedom are: waist rotation, lifting and stretching of the arm and opening and closing of the gripper. The designs of the main components are: a mobile chassis, parallel rails, horizontal rails and manipulator. The teaching robot designed has the features of low cost, easy to regulation, good repeatability and it has good promotion and application prospects in the field of teaching.

Improved Development Cycle of a Compliant Manipulator

2003 ◽  
Author(s):  
Stephen L. Canfield ◽  
Patrick V. Hull ◽  
James W. Beard
Keyword(s):  
Design Process ◽  
Design Methodology ◽  
Low Cost ◽  
Parallel Architecture ◽  
Degree Of Freedom ◽  
Modeling Tools ◽  
Multiple Features ◽  
Positioning Accuracy ◽  
Development Cycle ◽  
Three Degree Of Freedom

Application of the compliant design methodology to manipulators has held the promise of delivering manipulators with many significant advantages, including low cost, small size, low backlash and friction, and high positioning accuracy. This approach has been demonstrated in part by Canfield et. al., [1] to a class of three-degree-of-freedom manipulators based on a specific parallel architecture topology. In [1], the authors’ intent was to develop two compliant manipulators that exhibit several of the features associated with compliant devices. However, upon review of the manipulators resulting from this work it is observed that many of the benefits that were expected were lost at some point in the design process, resulting in manipulators that were large, expensive and suffered significantly from required assembly and inaccuracies in manufacture. This paper will revisit the problem addressed in [1], using the modeling tools demonstrated in that paper but will present several improved development measures that will result in manipulators that exhibit multiple features promised by compliant devices. The resulting manipulators will then be compared against the manipulators from [1] with a summary of the performance and characteristics of each given and evaluated.

Design of an Anthropomorphic Upper Extremity Prosthesis

2006 ◽  
Author(s):  
Kevin B. Fite ◽  
Keith W. Wait ◽  
Thomas J. Withrow ◽  
Michael Goldfarb
Keyword(s):  
Degree Of Freedom ◽  
Skeletal Structure ◽  
Direct Drive ◽  
Gas Generator ◽  
Dexterous Manipulation ◽  
Pneumatic Actuators ◽  
Position Sensing ◽  
Human Arm ◽  
Normal Human ◽  
Three Degree Of Freedom

This paper describes the design of a 21 degree-of-freedom, nine degree-of-actuation, gas-actuated arm prosthesis for transhumeral amputees. The arm incorporates a direct-drive elbow and three degree-of-freedom wrist, in addition to a 17 degree-of-freedom underactuated hand effected by five actuators. The anthropomorphic device includes full position and force sensing capability for each actuated degree of freedom and integrates a monopropellant-powered gas generator to provide on-board power for untethered operation. Design considerations addressed in this paper include the sizing of pneumatic actuators based on the requisite output energy at each joint; the development of small low-power servovalves for use with hot/cold gases; the design of compact joints with integrated position sensing; and the packaging of the actuators, on-board power, and skeletal structure within the volumetric envelope of a normal human forearm and elbow. The resulting arm prototype is intended to approach the dexterous manipulation capabilities of its anatomical counterpart while delivering approximately 50% of the force and power output of an average human arm.

scholarly journals Development of a Compact Three-Degree-of-Freedom Laser Measurement System with Self-Wavelength Correction for Displacement Feedback of a Nanopositioning Stage

2018 ◽  
Vol 8 (11) ◽  
pp. 2209 ◽  
Author(s):  
Yindi Cai ◽  
Zhifeng Lou ◽  
Siying Ling ◽  
Bo-syun Liao ◽  
Kuang-chao Fan
Keyword(s):  
Laser Diode ◽  
Low Cost ◽  
Michelson Interferometer ◽  
Optical Path Difference ◽  
Path Difference ◽  
Degree Of Freedom ◽  
Laser Source ◽  
Laser Measurement ◽  
Length Unit ◽  
Three Degree Of Freedom

This paper presents a miniature three-degree-of-freedom laser measurement (3DOFLM) system for displacement feedback and error compensation of a nanopositioning stage. The 3DOFLM system is composed of a miniature Michelson interferometer (MMI) kit, a wavelength corrector kit, and a miniature autocollimator kit. A low-cost laser diode is employed as the laser source. The motion of the stage can cause an optical path difference in the MMI kit so as to produce interference fringes. The interference signals with a phase interval of 90° due to the phase control are detected by four photodetectors. The wavelength corrector kit, based on the grating diffraction principle and the autocollimation principle, provides real-time correction of the laser diode wavelength, which is the length unit of the MMI kit. The miniature autocollimator kit based on the autocollimation principle is employed to measure angular errors and compensate induced Abbe error of the moving table. The developed 3DOFLM system was constructed with dimensions of 80 mm (x) × 90 mm (y) × 20 mm (z) so that it could be embedded into the nanopositioning stage. A series of calibration and comparison experiments were carried out to test the performance of this system.

Control System Design for AC-DC Three-Degree-of-Freedom Hybrid Magnetic Bearing

2012 ◽  
Vol 150 ◽  
pp. 144-147 ◽  
Author(s):  
Wei Yu Zhang ◽  
Ying Ruan ◽  
Xiao Yan Diao ◽  
Huang Qiu Zhu
Keyword(s):  
Control System ◽  
System Design ◽  
High Speed ◽  
Manufacturing Industry ◽  
Block Diagram ◽  
Low Cost ◽  
Magnetic Bearing ◽  
Degree Of Freedom ◽  
Control System Design ◽  
Three Degree Of Freedom

To fulfil the objective of high speed, high precision and intelligence in the modern equipment and advanced manufacturing industry, the magnetic bearing is requested to have small volume, low cost and low consumption. In this paper, an AC-DC three-degree-of-freedom hybrid magnetic bearing (AC-DC-3DOF-HMB) is studied, which integrates radial bearing and axial bearing in one of the magnetic bearing. The configuration and principle of AC-DC-3DOF-HMB are expounded, and the mathematical models of suspension forces are given. Then based on the function block diagram of AC-DC-3DOF-HMB control system, its hardware and software configuration are designed. The experiment results show that the rotor can be suspended stably with three degrees of freedom and has a good performance in anti- interference, and the feasibility of the control system design can be verified.

scholarly journals Effect of Curing Temperature on the Mechanical Strength of Alkali Activated Laterite Geopolymeric Samples

2021 ◽  
Author(s):  
Ahmad Fahmi ◽  
◽  
Alireza Babaeian amini ◽  
Yaser Marabi ◽  
Sohrab Rafati Zavaragh ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Mechanical Strength ◽  
Sodium Hydroxide ◽  
Building Materials ◽  
Sodium Hydroxide Solution ◽  
Low Cost ◽  
High Strength ◽  
Curing Temperature ◽  
Green Materials ◽  
New Type

A huge amount of carbon dioxide is released in the Portland cement production process. A large quantity of greenhouse gases is produced because of the significant amount of energy consumption via making bricks through firing. Using the pozzolanic sources containing the aluminosilicate and alkaline reagents, a new type of green materials called geopolymeric materials are produced with quite lower environmental hazards. The use of laterite as an iron-rich aluminosilicate material has a high potential for building materials. In this study, the effect of the curing temperature and characteristics of the alkaline reagent including the concentration of sodium hydroxide solution and the water-glass to sodium hydroxide mass mixing ratio on the mechanical strength of the laterite-based, oven-cured geopolymer samples was investigated. The results showed that the curing temperature had a significant effect on the compressive strength of the laterite-based geopolymer samples so that with a 15°C change at the curing temperature, the compressive strength of the samples could be multiplied and a sharp increase in the mechanical strength could occur. Also, according to the results of this study, the 6 M sodium hydroxide is recommended for the construction of the laterite-based geopolymer materials with low cost and relatively high strength, and for the construction of higher-strength building materials, the 14 M sodium hydroxide is recommended.

Low-cost biodiesel production using waste oil and catalyst

2020 ◽  
pp. 0734242X2093517
Author(s):  
Raheleh Talavari ◽  
Shokoufe Hosseini ◽  
GR Moradi
Keyword(s):  
Electron Microscopy ◽  
Fossil Fuels ◽  
Building Materials ◽  
Raw Materials ◽  
Low Cost ◽  
High Strength ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Waste Frying Oil ◽  
X Ray

With the production of renewable biofuels, concerns about the end of fossil fuels have been partially eliminated. On the other hand, the utilization of low-cost and waste materials to provide the raw essential substances to manufacture these fuels is of paramount importance. Biodiesel is one of these fuels and the required raw materials for the reaction are oil (triglycerides), alcohol and catalyst. In this work, travertine stone powder (as waste in the manufacture of building materials) was used as a catalyst and waste frying oil as a source of triglyceride for biodiesel production. Using thermogravimetric and X-ray diffraction analysis, optimum temperature for catalyst calcination was selected at 900°C. Furthermore, X-ray fluorescence, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller, transmission electron microscopy and scanning electron microscopy analyses were performed. Using the design of experiments Response Surface Methodology, the optimum reaction conditions for biodiesel production yield of 97.74% were: reaction temperature 59.52°C (~60°C), time 3.8 h (228 min), catalyst concentration 1.36 wt.% and the methanol to oil molar ratio of 11:6. After reusing four times, the catalyst efficiency was reduced a little, and the biodiesel yield was 89.84%, indicating high strength and stability of the catalyst.

scholarly journals Methods for determination of acoustic properties of building materials

2019 ◽  
Vol 282 ◽  
pp. 02061
Author(s):  
Lukáš Fiala ◽  
Petr Konrád ◽  
Robert Černý
Keyword(s):  
Urban Areas ◽  
Building Materials ◽  
Heavy Traffic ◽  
Harmonic Signal ◽  
Steel Sample ◽  
Acoustic Properties ◽  
Acoustic Insulation ◽  
Reverberation Chambers ◽  
High Level

Experimental determination of acoustic properties of building materials is an important task gaining higher importance due to demand for materials suitable for constructions located in places with high level of noise, typically in urban areas and places close to the areas with heavy traffic. In this paper, two types of experimental setups are arranged, and tested on steel prism and brick block. Transmitter-receiver method is based on exciting the tested material by one period of harmonic signal and analysis of response on two accelerometers placed on the excited and the opposite side of the sample. The second method is based on measurement of the sound pressure level in a system of two reverberation chambers by precise microphones and vibration analyzer. Transmitter-receiver measurement conducted on steel sample revealed the fact that further adjustment of the measurement setup and successive analysis is necessary. Measurement in reverberation chambers is convenient for comparison of acoustic insulation ability of heterogeneous building materials.

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