Advanced Techniques for Measuring Structural Mobilities

1988 ◽  
Vol 110 (3) ◽  
pp. 345-349 ◽  
Author(s):  
J. A. Fabunmi ◽  
F. A. Tasker
Keyword(s):  
Frequency Response ◽  
General Equation ◽  
Theoretical Basis ◽  
Weighting Function ◽  
Experimental Results ◽  
Expected Improvement ◽  
Response Functions ◽  
Proper Selection ◽  
Special Cases ◽  
Selection Of

A unified formulation of the equations for estimating structural frequency response functions is presented. The more popular approaches are shown to be special cases of a general equation which involves a weighting function, the proper selection of which can yield substantial improvements in the accuracy and efficiency of the measurement process. The theoretical basis for selecting the weighting function is also presented, along with experimental results which confirm the expected improvement in accuracy of the advanced formulations over existing methods.

Dynamical theory of neutron diffraction

1978 ◽  
Vol 56 (10) ◽  
pp. 1261-1288 ◽  
Author(s):  
V. F. Sears
Keyword(s):  
Neutron Diffraction ◽  
Theoretical Basis ◽  
Dynamical Theory ◽  
Experimental Results ◽  
Neutron Interferometry ◽  
New Techniques ◽  
The Past ◽  
Neutron Optics ◽  
Coherent Wave ◽  
Special Cases

We present a review of the dynamical theory of neutron diffraction by macroscopic bodies which provides the theoretical basis for the study of neutron optics. We consider both the theory of dispersion, in which it is shown that the coherent wave in the medium satisfies a macroscopic one-body Schrödinger equation, and the theory of reflection, refraction, and diffraction in which the above equation is solved for a number of special cases of interest. The theory is illustrated with the help of experimental results obtained over the past 10 years by a number of new techniques such as neutron gravity refractometry, Pendellösung interference, and neutron interferometry.

Line Contact Deformation: A Cylinder Between Two Flat Plates

1981 ◽  
Vol 103 (1) ◽  
pp. 21-25 ◽  
Author(s):  
M. R. Hoeprich ◽  
H. Zantopulos
Keyword(s):  
Plane Strain ◽  
General Equation ◽  
Roller Bearing ◽  
Experimental Results ◽  
Line Contact ◽  
Contact Deformation ◽  
Flat Plates ◽  
Special Cases ◽  
Analytical Work

Various line contact deformation equations used in roller bearing technology are analyzed. Many of these deformation equations, primarily involving plane strain, are shown to be special cases of a general equation derived in this paper. Experimental results are also presented to support the results of the analytical work.

Change of modal parameters due to crack growth in a tripod tower platform

1993 ◽  
Vol 20 (5) ◽  
pp. 801-813 ◽  
Author(s):  
Yin Chen ◽  
A. S. J. Swamidas
Keyword(s):  
Finite Element ◽  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Experimental Results ◽  
Modal Testing ◽  
Modal Parameters ◽  
Response Functions ◽  
Frequency Response Functions ◽  
Strain Frequency

Strain gauges, along with an accelerometer and a linear variable displacement transducer, were used in the modal testing to detect a crack in a tripod tower platform structure model. The experimental results showed that the frequency response function of the strain gauge located near the crack had the most sensitivity to cracking. It was observed that the amplitude of the strain frequency response function at resonant points had large changes (around 60% when the crack became a through-thickness crack) when the crack grew in size. By monitoring the change of modal parameters, especially the amplitude of the strain frequency response function near the critical area, it would be very easy to detect the damage that occurs in offshore structures. A numerical computation of the frequency response functions using finite element method was also performed and compared with the experimental results. A good consistency between these two sets of results has been found. All the calculations required for the experimental modal parameters and the finite element analysis were carried out using the computer program SDRC-IDEAS. Key words: modal testing, cracking, strain–displacement–acceleration frequency response functions, frequency–damping–amplitude changes.

scholarly journals Multiple Bandwidth Design of Micro strip Antenna for Future Wireless Communication

2019 ◽  
Vol 8 (2) ◽  
pp. 5135-5138 ◽  
Keyword(s):  
Wireless Communication ◽  
Frequency Band ◽  
Return Loss ◽  
Experimental Results ◽  
Proper Selection ◽  
Maximum Gain ◽  
Different Characteristics ◽  
Selection Of ◽  
Multi Band

We have presented a design of multi-band micro strip antenna which is suitable for operating at a higher frequency and with moderate bandwidth also. Proper selection of dimension, patch, and position of feed is taken into consideration to achieve the target properties of the antenna. Different characteristics of antenna like return loss, VSWR, gain, directivity, and efficiency are verified for different frequencies. The maximum gain of the antenna is found to be more than 3dB at different frequencies and also achieves multiple bandwidths in the direction of max radiation. The proposed structure of the antenna is fabricated, simulated, and tested for obtaining the preferred performance in terms of S11, VSWR, gain and efficiency. The experimental results are verified with simulated results which are in good in accord. Proposed antenna bandwidth is found to be 200MHz to 700 MHz with frequency band from 5.70 GHz to 12.60 GHz.

Effects of Atmospheric Conditions on the Mechanical Properties of Tires

2012 ◽  
Vol 232 ◽  
pp. 14-18 ◽  
Author(s):  
Zbigniew Olszewski ◽  
Konrad J. Waluś
Keyword(s):  
Mechanical Properties ◽  
Measuring Equipment ◽  
Weather Conditions ◽  
Road Surface ◽  
Experimental Results ◽  
Atmospheric Conditions ◽  
Operational Parameters ◽  
Proper Selection ◽  
Safe Driving ◽  
Selection Of

Safe driving requires from the driver several visual-mental activities (perception, Proper selection of the tires depending on the season allows for optimizing the level of risk associated with driving in varying weather conditions. Properties tires used in the vehicle operational parameters show variability of depending on temperature, leading consequently to change the characteristics of the traction of the vehicle. Understanding the nature of these relationships is essential to determine the nature interaction. tires and road surface This paper presents experimental results hardness of tires under normal traffic using a mobile measuring equipment.

Enhancement of the `auto-indexing' method for cell determination in four-circle diffractometry

1984 ◽  
Vol 17 (5) ◽  
pp. 334-336 ◽  
Author(s):  
W. Clegg
Keyword(s):  
Reduction Procedure ◽  
Proper Selection ◽  
Lattice Vector ◽  
Cell Determination ◽  
Reflection Data ◽  
Vector Generation ◽  
Indexing Method ◽  
Special Cases ◽  
Direct Lattice ◽  
Selection Of

Enhancements in the auto-indexing procedure for cell determination improve its power and reliability. A proper selection of three basis reflections for construction of an initial subcell is essential. A standard cell-reduction procedure applied to the subcell, and the calculation of appropriate limits for the direct-lattice-vector generation integers, make a comprehensive coverage of the direct space efficient and effective. Refinement of the generated lattice vectors against all the available reflection data makes assignment of the correct unit cell easier and more reliable. Generation of some additional long vectors is recommended in special cases.

Design and Implementation of 32-Bit High Valency Jackson Adders

2017 ◽  
Vol 26 (07) ◽  
pp. 1750123 ◽  
Author(s):  
N. Poornima ◽  
V. S. Kanchana Bhaaskaran
Keyword(s):  
Efficient Solution ◽  
Experimental Results ◽  
Performance Parameters ◽  
Proper Selection ◽  
Word Size ◽  
Design And Implementation ◽  
Recurrence Equations ◽  
Parallel Prefix ◽  
Design Requirements ◽  
Selection Of

Parallel prefix addition offers a highly efficient solution to most of the applications which requires fast addition of two binary numbers. An efficient adder design demands proper selection of recurrence equations and its realization. There are different recursion equations like Weinberger recursion, Ling recursion, Jackson recursion, to name a few, available to suit a variety of design requirements. In this work, we have proposed adders based on Jackson recursion. In these adders, the complexity found in generate term is reduced at all the levels of the carry graph to optimize the adder performance parameters. The proposed adder structures are implemented for a word size of 32-bit based on the Jackson recursion equations for valency-4 and valency-5. The synthesis results reveal that the high-valency Jackson adder structures are superior in terms of power and area over the Ling adders for comparable delay values. Experimental results obtained reveals that an average of [Formula: see text] and [Formula: see text] savings in area and power, respectively, are achieved by the proposed adders, as compared to Ling adders for the same word size. Furthermore, the proposed adders demonstrate enhanced area-delay and the power-delay values compared to the adders based on the Weinberger’s recursion.

Locating Damage In Waveguides From Point FRF Measurements

2007 ◽  
Vol 347 ◽  
pp. 583-588
Author(s):  
Simon P. Shone ◽  
Brian R. Mace ◽  
Tim P. Waters
Keyword(s):  
Fourier Transform ◽  
Dispersion Relation ◽  
Frequency Response ◽  
Inverse Fourier Transform ◽  
Spatial Domain ◽  
Experimental Results ◽  
Response Functions ◽  
Frequency Response Functions ◽  
Wavenumber Domain ◽  
Unknown Damage

A method is presented for locating discontinuities in a uniform waveguide from two or more point frequency response functions (FRFs). The phase of the FRF exhibits modulation when plotted against wavenumber because of interference of waves reflected from the discontinuity, and this is related to the distance of the excitation point from the discontinuity. Such discontinuities might be known boundaries or unknown damage sites. An inverse Fourier transform is used to transform from the wavenumber domain to the spatial domain in order to extract the locations of the discontinuities. The use of the transform relies upon knowledge of the dispersion relation for the waveguide. Experimental results are presented for several uniform isotropic beams which were damaged to differing extents by sawing transverse slots in them. The results show the method to be successful in locating the slots.

Design of a Robust H∞ Controller for a Magnetic Levitation System

2011 ◽  
Vol 301-303 ◽  
pp. 1356-1362
Author(s):  
Geng Zhang ◽  
Jie Li
Keyword(s):  
Magnetic Levitation ◽  
Weighting Function ◽  
Experimental Results ◽  
Loading Capacity ◽  
Levitation System ◽  
Magnetic Levitation System ◽  
Selection Of ◽  
Function Matrix

The magnetic levitation system is nonlinear and inherently unstable. In order to improve its anti-interference performance and its loading capacity, a robust H∞ controller is designed based on the H∞theory. The selection of the weighting function matrix is discussed for both the sensitivity and the complementary sensitivity of the H∞ controller. Simulation and experimental results show that the H∞ controller works effectively with excellent precision and robustness.

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