scholarly journals Investigation on the critical parameters affecting the working design dynamics of a torque motor employed in an electro-hydraulic servovalve

SIMULATION ◽  
2018 ◽  
Vol 95 (1) ◽  
pp. 31-49 ◽  
Author(s):  
Sharan A S ◽  
Somashekhar S Hiremath ◽  
C S Venkatesha ◽  
S Karunanidhi
Keyword(s):  
Electrical Signal ◽  
Critical Parameters ◽  
Fe Model ◽  
Test Set ◽  
Effective Dynamics ◽  
Novel Approach ◽  
Set Up ◽  
Experimental Values ◽  
Simulation Parameters ◽  
Good Agreement

The torque motor is an intricate assembly in electro-hydraulic technology and plays a crucial role in converting the electrical signal into controlled mechanical output signal. It involves many precise components, such as the feedback spring, armature and its coil, permanent magnet, feed pipe, flexure shaft, jetpipe, and flexure support. The components are embedded together as a single operating component. Each component contributes to the effective dynamics of the system. The present paper proposes a novel approach to investigate the effect of critical parameters on the working design dynamics of the torque motor employed in the jetpipe electro-hydraulic servovalve. Based on the principles of mechatronics, a mathematical model is developed. The model-based design approach is employed to investigate the dynamics of the system. The required simulation parameters of the critical and precision components were obtained from solid and finite element (FE) models. The solid and FE models of the critical and precision components were first analyzed with suitable boundary and loading conditions to establish the stiffness. To validate the obtained FE results, experiments were carried out with a specially designed and fabricated test set-up. Based on the basic principle of electromagnetics, a nonlinear FE model of torque motor is analyzed for magnetic field distribution, the torque developed, and armature and jetpipe deflection for varied input current. From the results obtained, good agreement was observed between FE, simulated, and experimental values. The present novel approach enables one to improve the working design dynamics of the torque motor.

Comparative study of the weft-knitted strain sensors

2016 ◽  
Vol 46 (5) ◽  
pp. 1212-1240 ◽  
Author(s):  
Ozgur Atalay ◽  
Asli Tuncay ◽  
Muhammad D Husain ◽  
William R Kennon
Keyword(s):  
Electrical Signal ◽  
Strain Sensors ◽  
Equivalent Resistance ◽  
Strain Sensing ◽  
Test Set ◽  
Signal Drift ◽  
Fabric Structure ◽  
Conductive Yarns ◽  
Manufacturing Techniques ◽  
Set Up

In this study, weft-knitted strain-sensing structures are described, along with the materials and manufacturing techniques required to produce the fabrics on a computerised flat-bed knitting machine. Knitted sensing fabrics with conductive yarns, i.e. silver-plated nylon yarn and polyester-blended stainless steel yarn have been created with different design possibilities. A laboratory test set-up was built to characterise the knitted sensors and the resulting equivalent resistance under the different level of strains. The most successful samples have been realised through a series of single conductive courses within the interlock base fabric structure using silver-plated nylon in terms of responsivity, repeatability and lower electrical signal drift. Deficiencies associated with strain-sensing structures realised through the intermeshing of conductive yarns have also been addressed.

Development and Validation of Subject-Specific Finite Element Models for Blunt Trauma Study

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Weixin Shen ◽  
Yuqing Niu ◽  
Robert F. Mattrey ◽  
Adam Fournier ◽  
Jackie Corbeil ◽  
...  
Keyword(s):  
Finite Element ◽  
Ct Images ◽  
Fe Model ◽  
Rib Cage ◽  
Abdominal Organs ◽  
Subject Specific ◽  
Experimental Values ◽  
Thoracic And Abdominal ◽  
Development And Validation ◽  
Good Agreement

This study developed and validated finite element (FE) models of swine and human thoraxes and abdomens that had subject-specific anatomies and could accurately and efficiently predict body responses to blunt impacts. Anatomies of the rib cage, torso walls, thoracic, and abdominal organs were reconstructed from X-ray computed tomography (CT) images and extracted into geometries to build FE meshes. The rib cage was modeled as an inhomogeneous beam structure with geometry and bone material parameters determined directly from CT images. Meshes of soft components were generated by mapping structured mesh templates representative of organ topologies onto the geometries. The swine models were developed from and validated by 30 animal tests in which blunt insults were applied to swine subjects and CT images, chest wall motions, lung pressures, and pathological data were acquired. A comparison of the FE calculations of animal responses and experimental measurements showed a good agreement. The errors in calculated response time traces were within 10% for most tests. Calculated peak responses showed strong correlations with the experimental values. The stress concentration inside the ribs, lungs, and livers produced by FE simulations also compared favorably to the injury locations. A human FE model was developed from CT images from the Visible Human project and was scaled to simulate historical frontal and side post mortem human subject (PMHS) impact tests. The calculated chest deformation also showed a good agreement with the measurements. The models developed in this study can be of great value for studying blunt thoracic and abdominal trauma and for designing injury prevention techniques, equipments, and devices.

Experimental Values of Solubility of Organic Compounds in Water for a Wide Range of Temperature Values − A New Experimental Technique

2010 ◽  
Vol 297-301 ◽  
pp. 1244-1249 ◽  
Author(s):  
João M.P.Q. Delgado ◽  
M. Vázquez da Silva
Keyword(s):  
Salicylic Acid ◽  
Benzoic Acid ◽  
Organic Compounds ◽  
Experimental Technique ◽  
Empirical Correlations ◽  
Wide Range ◽  
Set Up ◽  
Experimental Values ◽  
Good Agreement

This paper describes a simple experimental technique, easy to set-up in a laboratory, for the measurement of solute solubility in liquids (or gases). Experimental values of solubility were determined for the dissolution of benzoic acid in water and salicylic acid in water, at temperatures between 5°C and 70°C. The solubility experimental values obtained are in good agreement with the theoretical values of solubility and the empirical correlations presented in literature. The results show that it is possible to obtain good results for solubility values, using a simple and inexpensive experimental technique.

scholarly journals A preliminary approach to study the behavior of human fingertip at contact via experimental test and numerical model

ACTA IMEKO ◽  
2017 ◽  
Vol 6 (2) ◽  
pp. 81
Author(s):  
Maria Laura D'Angelo ◽  
Ferdinando Cannella ◽  
Mariapaola D'Imperio ◽  
Matteo Bianchi
Keyword(s):  
Experimental Data ◽  
Element Model ◽  
Fe Model ◽  
Proof Of Concept ◽  
Pressure Contour ◽  
Set Up ◽  
Deformation Models ◽  
Fundamental Action ◽  
Good Agreement

<p>How human fingertip deforms during the interaction with the environment represents a fundamental action that shapes our perception of external world. In this work, we present the <em>proof of concept</em> of an experimental <em>in vivo</em> set up that enables to characterize the mechanical behavior of human fingertip, in terms of contact area, force and a preliminary estimation of pressure contour, while it is put in contact against a flat rigid surface. Experimental outcomes are then compared with the output of a 3D Finite Element Model (FEM) of the human fingerpad, built upon existing validated models. The good agreement between numerical and experimental data suggests the correctness of our procedure for measurement acquisitions and finger modeling. Furthermore, we will also discuss how our experimental data can be profitably used to estimate strain limiting deformation models for tactile rendering, while the here reported 3D FE model has also been profitably employed to investigate hypotheses on human tactile perception.</p>

scholarly journals Influence of the Nose Radius on the Machining Forces Induced during AISI-4140 Hard Turning: A CAD-Based and 3D FEM Approach

Micromachines ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 798 ◽  
Author(s):  
Anastasios Tzotzis ◽  
César García-Hernández ◽  
José-Luis Huertas-Talón ◽  
Panagiotis Kyratsis
Keyword(s):  
Feed Rate ◽  
Cutting Speed ◽  
Cutting Conditions ◽  
Critical Parameters ◽  
Depth Of Cut ◽  
Fe Model ◽  
Nose Radius ◽  
3D Fem ◽  
Force Components ◽  
Experimental Values

The present study investigated the performance of three ceramic inserts in terms of the micro-geometry (nose radius and cutting edge type) with the aid of a 3D finite element (FE) model. A set of nine simulation runs was performed according to three levels of cutting speed and feed rate with respect to a predefined depth of cut and tool nose radius. The yielded results were compared to the experimental values that were acquired at identical cutting conditions as the simulated ones for verification purposes. Consequently, two more sets of nine simulations each were carried out so that a total of 27 turning simulation runs would adduce. The two extra sets corresponded to the same cutting conditions, but to different cutting tools (with varied nose radius). Moreover, a prediction model was established based on statistical methodologies such as the response surface methodology (RSM) and the analysis of variance (ANOVA), further investigating the relationship between the critical parameters (cutting speed, feed rate, and nose radius) and their influence on the generated turning force components. The comparison between the experimental values of the cutting force components and the simulated ones demonstrated an increased correlation that exceeded 89%. Similarly, the values derived from the statistical model were in compliance with the equivalent FE model values due to the verified adequacy.

scholarly journals Laboratory Measurements of Light Scattering by Dust Particles

1996 ◽  
Vol 150 ◽  
pp. 409-413
Author(s):  
Patrick P. Combet ◽  
Philippe L. Lamy
Keyword(s):  
Light Scattering ◽  
Laser Beam ◽  
Mie Theory ◽  
Spherical Particles ◽  
Dust Particles ◽  
Laboratory Measurements ◽  
Scattering Function ◽  
Hene Laser ◽  
Set Up ◽  
Good Agreement

AbstractWe have set up an experimental device to optically study the scattering properties of dust particles. Measurements over the 8 — 174° interval of scattering angles are performed on a continuously flowing dust loaded jet illuminated by a polarized red HeNe laser beam. The scattering is averaged over the population of the dust particles in the jet, which can be determined independently, and give the “volume scattering function” for the two directions of polarization directly. While results for spherical particles are in good agreement with Mie theory, those for arbitrary particles show conspicuous deviations.

Systematic calculations of energy levels and transitions rates in Mo XXVIII

2020 ◽  
Vol 75 (8) ◽  
pp. 739-747
Author(s):  
Feng Hu ◽  
Yan Sun ◽  
Maofei Mei
Keyword(s):  
Energy Levels ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Data Sets ◽  
Electron Systems ◽  
Excitation Energies ◽  
Experimental Values ◽  
Qed Effects ◽  
Hyperfine Structures ◽  
Good Agreement

AbstractComplete and consistent atomic data, including excitation energies, lifetimes, wavelengths, hyperfine structures, Landé gJ-factors and E1, E2, M1, and M2 line strengths, oscillator strengths, transitions rates are reported for the low-lying 41 levels of Mo XXVIII, belonging to the n = 3 states (1s22s22p6)3s23p3, 3s3p4, and 3s23p23d. High-accuracy calculations have been performed as benchmarks in the request for accurate treatments of relativity, electron correlation, and quantum electrodynamic (QED) effects in multi-valence-electron systems. Comparisons are made between the present two data sets, as well as with the experimental results and the experimentally compiled energy values of the National Institute for Standards and Technology wherever available. The calculated values including core-valence correction are found to be in a good agreement with other theoretical and experimental values. The present results are accurate enough for identification and deblending of emission lines involving the n = 3 levels, and are also useful for modeling and diagnosing plasmas.

scholarly journals Innovative passive reinforcements for the gradual stabilization of a landslide according with the observational method

Landslides ◽  
2021 ◽  
Author(s):  
Lorenzo Brezzi ◽  
Alberto Bisson ◽  
Davide Pasa ◽  
Simonetta Cola
Keyword(s):  
Monitoring System ◽  
Low Cost ◽  
Economic Losses ◽  
Fe Model ◽  
Site Conditions ◽  
Observational Method ◽  
Rainy Period ◽  
Sustainable Solutions ◽  
Before And After ◽  
Set Up

AbstractA large number of landslides occur in North-Eastern Italy during every rainy period due to the particular hydrogeological conditions of this area. Even if there are no casualties, the economic losses are often significant, and municipalities frequently do not have sufficient financial resources to repair the damage and stabilize all the unstable slopes. In this regard, the research for more economically sustainable solutions is a crucial challenge. Floating composite anchors are an innovative and low-cost technique set up for slope stabilization: it consists in the use of passive sub-horizontal reinforcements, obtained by coupling a traditional self-drilling bar with some tendons cemented inside it. This work concerns the application of this technique according to the observational method described within the Italian and European technical codes and mainly recommended for the design of geotechnical works, especially when performed in highly uncertain site conditions. The observational method prescribes designing an intervention and, at the same time, using a monitoring system in order to correct and adapt the project during realization of the works on the basis of new data acquired while on site. The case study is the landslide of Cischele, a medium landslide which occurred in 2010 after an exceptional heavy rainy period. In 2015, some floating composite anchors were installed to slow down the movement, even if, due to a limited budget, they were not enough to ensure the complete stabilization of the slope. Thanks to a monitoring system installed in the meantime, it is now possible to have a comparison between the site conditions before and after the intervention. This allows the evaluation of benefits achieved with the reinforcements and, at the same time, the assessment of additional improvements. Two stabilization scenarios are studied through an FE model: the first includes the stabilization system built in 2015, while the second evaluates a new solution proposed to further increase the slope stability.

Dynamic characteristics of squeeze-type mount using magnetorheological fluid

2005 ◽  
Vol 219 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Y K Ahn ◽  
J-Y Ha ◽  
Y-H Kim ◽  
B-S Yang ◽  
M Ahmadian ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Experimental Analysis ◽  
Vibration Isolation ◽  
Dynamic Behaviour ◽  
Electrical Current ◽  
Magnetorheological Fluid ◽  
Test Set ◽  
Mr Fluid ◽  
Set Up ◽  
Stiffness And Damping

This paper presents an analytical and experimental analysis of the characteristics of a squeeze-type magnetorheological (MR) mount which can be used for various vibration isolation areas. The concept of the squeeze-type mount and details of the design of a squeeze-type MR mount are discussed. These are followed by a detailed description of the test set-up for evaluating the dynamic behaviour of the mount. A series of tests was conducted on the prototype mount built for this study, in order to characterize the changes occurring as a result of changing electrical current to the mount. The results of this study show that increasing electrical current to the mount, which increases the yield stress of the MR fluid, will result in an increase in both stiffness and damping of the mount. The results also show that the mount hysteresis increases with increase in current to the MR fluid, causing changes in stiffness and damping at different input frequencies.

The Reduction of Bias Error in Transfer Function Estimates Using FFT-Based Analyzers

1984 ◽  
Vol 106 (1) ◽  
pp. 29-35 ◽  
Author(s):  
P. Cawley
Keyword(s):  
Transfer Function ◽  
Random Excitation ◽  
Analogue Computer ◽  
Bias Error ◽  
Testing Time ◽  
Theoretical Predictions ◽  
Set Up ◽  
Modal Mass ◽  
Time Required ◽  
Good Agreement

The susceptibility to bias error of two methods for computing transfer (frequency response) functions from spectra produced by FFT-based analyzers using random excitation has been investigated. Results from tests with an FFT analyzer on a single degree-of-freedom system set up on an analogue computer show good agreement with the theoretical predictions. It has been shown that, around resonance, the bias error in the transfer function estimate H2 (Syy/Sxy*) is considerably less than that in the more commonly used estimate, H1 (Sxy/Sxx). The record length, and hence the testing time, required for a given accuracy is reduced by over 50 percent if the H2 calculation procedure is used. The analysis has also shown that if shaker excitation is used on lightly damped structures with low modal mass, it is important to minimize the mass of the force gage and the moving element of the shaker.

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