Shutters and blinds power operated. Safety in use. Measurement of the transmitted force

2015 ◽  
Keyword(s):  
Transmitted Force

Vibration Isolation From Harmonic Disturbances Through Use of Internally Rotating Masses

2015 ◽  
Author(s):  
Eric Smith ◽  
Al Ferri
Keyword(s):  
Kinetic Energy ◽  
Vibration Isolation ◽  
Harmonic Excitation ◽  
Impulsive Loading ◽  
Qualitative Behavior ◽  
Single Degree Of Freedom ◽  
Transmitted Force ◽  
A Chain ◽  
Isolation Systems ◽  
Parameter Values

This paper considers the use of a chain of translating carts or housings having internally rotating eccentric masses in order to accomplish vibration isolation. First a single degree-of-freedom system is harmonically excited to uncover the qualitative behavior of each rotating mass. The simple model is then expanded into a chain of housings, containing rotating eccentric masses, which are interconnected with springs. The internal rotating eccentric masses are damped along their circular pathway by means of linear viscous damping. Due to the lack of elastic or gravitational constraint on the rotating eccentric masses, they provide a nonlinear inertial coupling to their housings. Previous research has shown that such systems are capable of reducing shock or impulsive loading by converting some of the translational kinetic energy into rotational kinetic energy of the internal masses. This paper examines the potential for vibration isolation of a chain of such systems subjected to persistent, harmonic excitation. It is seen that the dynamics of these systems is very complicated, but that trends are observed which have implications for practical isolation systems. Using simulation studies, tradeoffs are examined between displacement and transmitted force for a range of physical parameter values.

scholarly journals Study on the V-ribbed Belt : The relation between Rid Deformation and transmitted force of the V-ribbed Belt

1986 ◽  
Vol 29 (253) ◽  
pp. 2317-2322 ◽  
Author(s):  
Sadao AMIJIMA ◽  
Toru FUJII ◽  
Takafumi KUl ◽  
Yoshikazu TANI ◽  
Masahiro INUKAI
Keyword(s):  
Transmitted Force

scholarly journals The Dynamic Response of the Vibrating Compactor Roller, Depending on the Viscoelastic Properties of the Soil

2020 ◽  
Vol 3 (2) ◽  
pp. 25
Author(s):  
Cornelia Dobrescu
Keyword(s):  
Dynamic Response ◽  
Soil Compaction ◽  
Viscoelastic Properties ◽  
Dynamic Effect ◽  
Pulse Response ◽  
Compaction Process ◽  
Response Curves ◽  
Soil Layers ◽  
Transmitted Force ◽  
Practical Engineering

The present paper addresses the problem of the dynamic response of a vibrating equipment for soil compaction. In essence, dynamic response vibrations are analysed by applying an inertial-type perturbing force. This is generated by rotating an eccentric mass with variable angular velocity, in order to reach the regime necessary to ensure the degree of compaction. The original character of the research is that during the compaction process, the soil layers with certain compositions of clay, sand, water and stabilizing substances change their rigidity and/or amortization. In this case, two situations were analysed, both experimentally and with numerical modelling, with special results and practical engineering conclusions, favourable to the evaluation of the interaction between vibrator roller–compacted ground. We mention that the families of amplitude–pulse and transmitted force–pulse response curves are presented, from which the dynamic effect in the compaction process results after each passage on the same layer of soil, until the necessary compaction state is reached.

Transfer Functions for Helical Springs

1969 ◽  
Vol 91 (4) ◽  
pp. 1011-1016 ◽  
Author(s):  
B. L. Johnson ◽  
E. E. Stewart
Keyword(s):  
Experimental Data ◽  
Experimental Investigation ◽  
Steady State ◽  
Transfer Functions ◽  
Helical Springs ◽  
Response Characteristics ◽  
Transmitted Force ◽  
Vibratory Motion ◽  
Frequency Response Characteristics ◽  
Displacement Force

This study reports the results of an analytical and experimental investigation of helical springs subjected to vibratory motion. Transfer functions are presented for both displacement and transmitted force as outputs with force as the input. Steady-state sinusoidal Magnitude Ratio (displacement—force) and Transmittance Ratio (force—force) are plotted along with substantiating experimental data. It is shown that an actual spring displays frequency response characteristics over most of the frequency spectrum that would render its function useless in many cases.

Design, Fabrication, and Testing of a Novel 3-DOF Energy Harvester With Single Piezoelectric Stack

2019 ◽  
Vol 142 (6) ◽  
Author(s):  
Zehao Wu ◽  
Qingsong Xu
Keyword(s):  
Energy Harvester ◽  
Experimental Studies ◽  
Force Transmission ◽  
Input Force ◽  
Transmission Mechanisms ◽  
Piezoelectric Energy ◽  
Transmitted Force ◽  
Force Components ◽  
Three Degree Of Freedom ◽  
Performance Results

Abstract This paper presents the design, fabrication, and testing of a novel single stack-based piezoelectric energy harvester (PEH) for harvesting energy from three-degree-of-freedom (3-DOF) force excitation. One uniqueness lies in that the 3-DOF energy harvesting is implemented by using one piezoelectric stack. To scavenge energy from the 3-DOF input force, the proposed PEH is constructed with several force transmission mechanisms and slider mechanisms. The direction of the input force is first changed by the force transmission mechanisms, and the redundant force components are eliminated by the slider mechanisms. The transmitted force is then amplified by a two-stage force amplifier mechanism to improve the electric power output. The key parameters were found by establishing an analytical model of the proposed PEH. The best output performance of the PEH is achieved by selecting and optimally designing the key parameters. A prototype harvester was fabricated, and several experimental studies were conducted to verify the device performance. Results show the effectiveness of the developed 3-DOF PEH under the input force applied in x-axis, y-axis or z-axis. Furthermore, the issues that affect the practical application are discussed.

scholarly journals Experimental study of the impact response of geocells as components of rockfall protection embankments

2009 ◽  
Vol 9 (2) ◽  
pp. 459-467 ◽  
Author(s):  
S. Lambert ◽  
P. Gotteland ◽  
F. Nicot
Keyword(s):  
Experimental Study ◽  
Numerical Model ◽  
Boundary Conditions ◽  
Composite Structures ◽  
Impact Force ◽  
Impact Response ◽  
Rigid Base ◽  
Transmitted Force ◽  
The Impact ◽  
Rockfall Protection

Abstract. Rockfall protection embankments are ground levees designed to stop falling boulders. This paper investigates the behaviour of geocells to be used as components of these structures. Geocells, or cellular confinement systems, are composite structures associating a manufactured envelope with a granular geomaterial. Single cubic geocells were subjected to the impact resulting from dropping a spherical boulder. The geocells were filled with fine or coarse materials and different boundary conditions were applied on the lateral faces. The response is analysed in terms of the impact force and the force transmitted by the geocell to its rigid base. The influence on the geocell response of both the fill material and the cell boundary conditions is analysed. The aim was to identify the conditions resulting in greatest reduction of the transmitted force and also to provide data for the validation of a specific numerical model.

Shock Isolation in Finite-Length Dimer Chains With Linear, Cubic, and Hertzian Spring Interactions

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Eric Smith ◽  
Aldo Ferri
Keyword(s):  
Numerical Simulations ◽  
Finite Length ◽  
Hertzian Contact ◽  
Mass Ratio ◽  
Transmitted Force ◽  
Parametric Studies ◽  
Shock Isolation ◽  
Isolation Systems ◽  
Chain Lengths ◽  
Isolation Performance

This paper investigates the use of finite 1:1 dimer chains to mitigate the transmission of shock disturbances. Dimer chains consist of alternating light and heavy masses with interconnecting compliance. Changing the mass ratio has provided interesting results in previous research. In particular, in the case of Hertzian contacts with zero-preload, certain mass ratios have revealed minimal levels of transmitted force. This paper examines this phenomenon from the perspective of utilizing it in practical isolation systems. The zero-preload Hertzian contact case is contrasted with chains connected by linear or cubic springs. Through numerical simulations, tradeoffs are examined between displacement and transmitted force. Parametric studies are conducted to examine how isolation performance changes with mass ratio, stiffness, and different chain lengths.

The Control of Engine Vibration Using Squeeze Film Dampers

1983 ◽  
Vol 105 (3) ◽  
pp. 525-529 ◽  
Author(s):  
R. Holmes
Keyword(s):  
Experimental Work ◽  
Squeeze Film ◽  
Vibration Isolator ◽  
Squeeze Film Damper ◽  
Engine Vibration ◽  
Transmitted Force ◽  
Squeeze Film Dampers ◽  
Jump Phenomena ◽  
Theoretical Predictions ◽  
In Series

This paper describes the following roles of a squeeze-film damper when used in gas turbine applications as a means of reducing vibration and transmitted force due to unbalance: (a) as an element in parallel with a soft spring in a vibration isolator; and (b) as an element in series with the stiffness of the engine pedestal. The effects of cavitation on performance are elucidated, and the dangers of jump phenomena and subsynchronous response are discussed. Experimental work is described in which both roles of the squeeze-film damper are investigated and the results are compared with theoretical predictions.

Effective Reduction of Peak Frequency in Hydraulic Engine Mounts

2010 ◽  
Author(s):  
Reza Tikani ◽  
Nader Vahdati ◽  
Saeed Ziaei-Rad
Keyword(s):  
Dynamic Stiffness ◽  
Peak Frequency ◽  
Design Parameters ◽  
Working Fluid ◽  
Working Fluids ◽  
Engine Mounts ◽  
Cabin Noise ◽  
Transmitted Force ◽  
Effective Reduction ◽  
Engine Mount

Hydraulic engine mounts are generally applied to the aerospace and the automotive applications for the purpose of cabin noise and vibration reduction. By careful selection of hydraulic mount design parameters, at a certain frequency, namely the notch frequency, the dynamic stiffness will be smaller than the static stiffness and cabin vibration and noise reduction is provided at that frequency. Literature review indicates that in all previous hydraulic engine mount designs, the dynamic stiffness increases after the notch frequency. This phenomenon is not desirable because of the increase in transmitted force to the air-frame. Here in this paper, a new hydraulic engine mount design is proposed that uses two working fluids. This new design has two notch frequencies and two peak frequencies. In this study, effective reduction of the peak frequencies has been demonstrated by using a controllable fluid as one of the mount’s working fluids and a non-controllable fluid as the 2nd working fluid. As a result, one can obtain a hydraulic engine mount design with only one notch frequency but no peak frequency. The new hydraulic engine mount design and its mathematical model are presented in details and some discussions on the simulation results are also included.

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