Simultaneous evaluation of bending and shear stiffness of wood I-joists by transverse vibration tests

2021 ◽  
Vol 243 ◽  
pp. 112643
Author(s):  
Sigong Zhang ◽  
Jianhui Zhou ◽  
Ying Hei Chui
Keyword(s):  
Transverse Vibration ◽  
Shear Stiffness ◽  
Simultaneous Evaluation ◽  
Vibration Tests

Research on the Vibration of Sheet Metal near the Zinc Pot Area in Continuous Hot-Dip Galvanizing Line

2011 ◽  
Vol 141 ◽  
pp. 471-477 ◽  
Author(s):  
Pei Min Xu ◽  
Biao Wang ◽  
Jin Jie Ye ◽  
Hai Juan Zhang ◽  
Zhi Lai Huang ◽  
...  
Keyword(s):  
Sheet Metal ◽  
Transverse Vibration ◽  
Cooling Tower ◽  
The Other ◽  
Control Parameters ◽  
Main Factors ◽  
Axially Moving ◽  
Vibration Tests ◽  
Air Knife ◽  
Excited Resonance

Large vibration of the sheet metal near the air knife is one of the main factors controlling the accuracy of thickness of the cladding zinc in continuous hot-dip galvanizing line. Lots of vibration tests are carried out on the strip and main equipments in the zinc pot area of a galvanizing line during downtime and operation in order to diagnose causes of the large vibration of the strip near the air knife. Theoretic foundation of adjustment of control parameters to suppress the strip vibration is established. Main mechanisms of large vibration of the strip are found by the theory of the transverse vibration of axially moving continua. The first one is the resonance of forced vibration induced by support movement aroused by passive rollers’ sloshing in the zinc pot, and the other is the parametrically excited resonance of the strip induced by tension fluctuation enlarged by local structural resonances of the cooling tower.

Modulus of Elasticity of Schizolobium amazonicum Wood Evaluated by Transversal Vibration Technique

2014 ◽  
Vol 912-914 ◽  
pp. 247-250 ◽  
Author(s):  
Diego Henrique de Almeida ◽  
Raquel Schmitt Cavalheiro ◽  
Fabiane Salles Ferro ◽  
Tiago Hendrigo de Almeida ◽  
André Luis Christoforo ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Specific Gravity ◽  
Moisture Content ◽  
Transverse Vibration ◽  
Modulus Of Elasticity ◽  
Low Density ◽  
Average Value ◽  
Vibration Technique ◽  
Small Incidence ◽  
Vibration Tests

Schizolobium amazonicum is being much used in Brazil for several purposes because, besides being a native Brazilian wood specie, has important features such as low density and small incidence of natural defects. At this point, researches with the purpose of obtaining further knowledge of their properties are being conducted to better targeting their use. The aim of this research is to evaluate the modulus of elasticity of structural size pieces of Schizolobium amazonicum wood using the technique of transverse vibration. Tests were carried out using 30 pieces (standard moisture content 12%) with sizes of 3 cm x 15 cm x 2.5 m. The average value of elastic modulus determined for lumber of Schizolobium amazonicum was interesting to its low specific gravity.

The Effect of Joints on the Transverse Vibration of a Simple Structure

1990 ◽  
Vol 204 (1) ◽  
pp. 37-42 ◽  
Author(s):  
F P E Dunne ◽  
M Heppenstall
Keyword(s):  
Mild Steel ◽  
Compressive Stress ◽  
Transverse Vibration ◽  
Reasonable Agreement ◽  
Simple Structure ◽  
Natural Frequencies ◽  
Theoretical Models ◽  
Experimental Results ◽  
Predicted Values ◽  
Vibration Tests

Transverse vibration tests were carried out on a cold-drawn mild steel tubular beam containing annular metal-to-metal joints. The tests were also carried out on an unjointed beam of the same dimensions. An axial compressive preload was applied giving a compressive stress in the range of 0–80 N/mm2. Joints between rough turned surfaces, between ground surfaces and mixed joints between both types of surface were used. Dynamic bending stiffnesses of the joints over the range of compressive stress were determined. Stiffness of the turned and mixed joints was found to be proportional to preload. Stiffness of ground joints increased with preload, but not proportionally. Theoretical models were developed to determine joint bending siffness and natural frequencies of transverse vibration of the jointed beams. Predicted values of joint bending stiffness for ground and turned joints were in reasonable agreement with the experimental results.

Flow-Induced Transverse Vibration of a Cantilevered Prism and Vibration-Generated Power Using Magnetostrictive Material

2013 ◽  
Author(s):  
Takahiro Kiwata ◽  
Makoto Yamaguchi ◽  
Takaaki Kono ◽  
Toshiyuki Ueno
Keyword(s):  
Transverse Vibration ◽  
Flexural Rigidity ◽  
Flow Direction ◽  
Response Amplitude ◽  
Rectangular Prism ◽  
Magnetostrictive Material ◽  
Side Ratio ◽  
Damping Parameter ◽  
Increment Rate ◽  
Vibration Tests

Free-vibration tests of a cantilevered rectangular prism with a side ratio of less than D/H = 0.5 (D, depth of the rectangular prism in the flow direction; H, height of a rectangular prism) that experiences low-speed galloping at a lower reduced velocity than the resonant reduced velocity were conducted in a water tunnel. We also carried out a power generation experiment using an iron-gallium alloy, which is a magnetostrictive material, to investigate the possibility of harvesting energy from a flow-induced transverse vibration. The effects of the side ratio of the rectangular prism and the configuration of a fin that was fitted on the back of a rectangular prism to increase the flexural rigidity on the response amplitude were investigated. The vibration of a rectangular prism with D/H = 0.1 occurred at a lower reduced velocity than that of the other rectangular prisms. This prism has the largest increment rate of the non-dimensional response amplitude ηrms for reduced velocity Vr, and the vibration has an uniform amplitude for each reduced velocity. The reduced velocity at the 20% non-dimensional response amplitude of a rectangular prism Vr0.2 decreases linearly with decreasing side ratio D/H. The response amplitude of the rectangular prism with D/H = 0.2 is only slightly dampened for all values of the reduced mass-damping parameter Cn. The values of Vr0.2 of the rectangular prism with a fin increased as the depth ratio of the fin increased. The response amplitude of the rectangular prism with/without a fin was found to be related to the second moment of area of the prism. The energy harvester using magnetostrictive material and a rectangular prism with D/H = 0.2 generates a maximum electric power of 8.8 mW.

ANALYSIS OF THE GENERAL EQUATIONS OF THE TRANSVERSE VIBRATION OF A PIECEWISE UNIFORM VISCOELASTIC PLATE

2020 ◽  
Vol 7 (3) ◽  
pp. 52-56
Author(s):  
MMATMATISA JALILOV ◽  
◽  
RUSTAM RAKHIMOV ◽  
Keyword(s):  
Cross Section ◽  
Transverse Vibration ◽  
Three Dimensional ◽  
Viscoelastic Plate ◽  
Constant Thickness ◽  
Regional Problem ◽  
Rigid Contact ◽  
Under Construction ◽  
Derivatives Of ◽  
Theoretical Results

This article discusses the analysis of the general equations of the transverse vibration of a piecewise homogeneous viscoelastic plate obtained in the “Oscillation of inlayer plates of constant thickness” [1]. In the present work on the basis of a mathematical method, the approached theory of fluctuation of the two-layer plates, based on plate consideration as three dimensional body, on exact statement of a three dimensional mathematical regional problem of fluctuation is stood at the external efforts causing cross-section fluctuations. The general equations of fluctuations of piecewise homogeneous viscoelastic plates of the constant thickness, described in work [1], are difficult on structure and contain derivatives of any order on coordinates x, y and time t and consequently are not suitable for the decision of applied problems and carrying out of engineering calculations. For the decision of applied problems instead of the general equations it is expedient to use confidants who include this or that final order on derivatives. The classical equations of cross-section fluctuation of a plate contain derivatives not above 4th order, and for piecewise homogeneous or two-layer plates the elementary approached equation of fluctuation is the equation of the sixth order. On the basis of the analytical decision of a problem the general and approached decisions of a problem are under construction, are deduced the equation of fluctuation of piecewise homogeneous two-layer plates taking into account rigid contact on border between layers, and also taking into account mechanical and rheological properties of a material of a plate. The received theoretical results for the decision of dynamic problems of cross-section fluctuation of piecewise homogeneous two-layer plates of a constant thickness taking into account viscous properties of their material allow to count more precisely the is intense-deformed status of plates at non-stationary external loadings.

Simultaneous Evaluation of Criteria and Alternatives (SECA) for Multi-Criteria Decision-Making

Informatica ◽  
2018 ◽  
Vol 29 (2) ◽  
pp. 265-280 ◽  
Author(s):  
Mehdi Keshavarz-Ghorabaee ◽  
Maghsoud Amiri ◽  
Edmundas Kazimieras Zavadskas ◽  
Zenonas Turskis ◽  
Jurgita Antucheviciene
Keyword(s):  
Decision Making ◽  
Multi Criteria Decision Making ◽  
Simultaneous Evaluation

FEATURES OF SIMULATING THE FORCE ACTIONS FROM A DAMAGED ENGINE AT GROUND VIBRATION TESTS OF AN AIRPLANE

2016 ◽  
Vol 47 (6) ◽  
pp. 649-663
Author(s):  
Regina Vladimirovna Leonteva ◽  
Vsevolod Igorevich Smyslov
Keyword(s):  
Ground Vibration ◽  
Vibration Tests

Tire Treadwear — A Comprehensive Evaluation of the Factors: Generic Type, Aspect Ratio, Tread Pattern, and Tread Composition Part IV: Laboratory Measurement of Mechanical Properties and Mechanical Actions of Tires Relating to Treadwear

1986 ◽  
Vol 14 (4) ◽  
pp. 264-291
Author(s):  
K. L. Oblizajek ◽  
A. G. Veith
Keyword(s):  
Mechanical Properties ◽  
Shear Stress ◽  
Contact Zone ◽  
Flexural Rigidity ◽  
Comprehensive Evaluation ◽  
Shear Stiffness ◽  
Shear Stresses ◽  
Lateral Shear ◽  
Band Bending ◽  
Tread Rubber

Abstract Treadwear is explained by specific mechanical properties and actions of tires. Rubber shear stresses in the contact zone between the tire and the road become large at large slip angles. When normal stresses are insufficient to prevent sliding at the rear of the footprint, wear occurs at a rate that depends on test severity. Two experimental approaches are described to relate treadwear to tire characteristics. The first uses transducers imbedded in a simulated road surface to obtain direct measurements of contact stresses on the loaded, freely-rolling, steered tires. The second approach is developed with the aid of a simple carcass, tread-band, tread-rubber tire model. Various tire structural configurations; characterized by carcass spring rate, edgewise flexural band stiffness, and tread rubber shear stiffness; are simulated and lateral shear stress response in the contact zone is determined. Tires featuring high band stiffness and low carcass stiffness generate lower lateral shear stress levels. Furthermore, coupling of tread-rubber stiffness and band flexural rigidity are important in determining level of shear stresses. Laboratory measurements with the described apparatus produced values of tread-band bending and carcass lateral stiffness for several tire constructions. Good correlation is shown between treadwear and a broad range of tire stiffness and test course severities.

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