scholarly journals Numerical and Experimental Study on Measuring Method of Rail Axial Stress of Continuous Welded Rails Based on Use of Resonant Frequency

2013 ◽  
Vol 54 (2) ◽  
pp. 118-125 ◽  
Author(s):  
Akira AIKAWA ◽  
Hirotaka SAKAI ◽  
Kazuhisa ABE
Keyword(s):  
Experimental Study ◽  
Resonant Frequency ◽  
Axial Stress ◽  
Measuring Method

Experimental Study of Liquid Slosh Dynamics in a Partially-Filled Tank

2009 ◽  
Vol 131 (7) ◽  
Author(s):  
Guorong Yan ◽  
Subhash Rakheja ◽  
Kamran Siddiqui
Keyword(s):  
Experimental Study ◽  
Resonant Frequency ◽  
Excitation Frequency ◽  
Longitudinal Mode ◽  
Longitudinal Force ◽  
Scale Model ◽  
Fill Volume ◽  
Pitch Moment ◽  
Close Proximity ◽  
Rigid Mass

This article reports on an experimental study conducted to investigate slosh forces and moments caused by fluid slosh within a partly-filled tank subjected to lateral and longitudinal excitations applied independently. The experiments were performed on a scale model cleanbore and a baffled tank with laterally placed single- and multiple-orifice baffles. The experiments were conducted for three different fill volumes and different types of excitations: continuous harmonic and single-cycle sinusoidal excitations of different amplitudes and discrete frequencies. The dynamic forces and moments caused by fluid slosh with the baffled and cleanbore tank configurations were measured for different fill volumes and excitations using three-axis dynamometers. It is shown that the resulting forces and moments comprise many spectral components that can be associated with the excitation, resonance, and vibration and beat frequencies. Modulation of excitation frequency with the resonant frequency was also evident for all fill conditions and tank configurations when the two were in close proximity. The results also showed that the peak amplifications of forces and moments occur in the vicinity of the resonant frequency. At higher frequencies, the peak magnitudes of the forces, however, reduced significantly to values lower than the inertial forces developed by an equivalent rigid mass. At a given excitation condition, the slosh force amplitude increased with a decrease in the fill volume. It was also observed that the presence of baffles has negligible effect on the lateral slosh force and the corresponding resonant frequency. However, it caused a significant increase in the longitudinal mode resonant frequency. The baffles greatly reduced the amplifications in longitudinal force and pitch moment under longitudinal acceleration excitations.

An Experimental Study on the Compressive Behavior of CFRP-Confined High- and Ultra High-Strength Concrete

2013 ◽  
Vol 671-674 ◽  
pp. 1860-1864 ◽  
Author(s):  
Thomas Vincent ◽  
Togay Ozbakkloglu
Keyword(s):  
Experimental Study ◽  
High Strength Concrete ◽  
Axial Stress ◽  
Concrete Strength ◽  
Experimental Studies ◽  
High Strength ◽  
Compressive Behavior ◽  
Stress Strain ◽  
Strength Concrete ◽  
Ductile Behavior

It is well established that external confinement of concrete with fiber reinforced polymer (FRP) sheets results in significant improvements on the axial compressive behavior of concrete. This understanding has led to a large number of experimental studies being conducted over the last two decades. However, the majority of these studies have focused on normal strength concretes (NSC) with compressive strengths lower than 55 MPa, and studies on higher strength concretes have been very limited. This paper presents the results of an experimental study on the compressive behavior of FRP confined high- and ultra high-strength concrete (HSC and UHSC) with average compressive strengths of 65 and 100 MPa. A total of 29 specimens were tested under axial compression to investigate the influence of key parameters such as concrete strength and method of confinement. All specimens were cylindrical, confined with carbon FRP and were 305 mm in height and 152 mm in diameter. Results obtained from the laboratory testing were graphically presented in the form of axial stress-strain relationships and key experimental outcomes are discussed. The results of this experimental study indicate that above a certain confinement threshold, FRP-confined HSC and UHSC exhibit highly ductile behavior. The results also indicate that FRP-wrapped specimens perform similar to concrete-filled FRP tube (CFFT) specimens at ultimate condition, however notable differences are evident at the transition region when comparing stress-strain curves.

Experimental Study of Nonlinear Effects under Torsion of the Uniform Cylinder with Initially Circular Cross Section

2015 ◽  
Vol 243 ◽  
pp. 29-34
Author(s):  
V.P. Bachurikhin ◽  
I.E. Keller ◽  
A.F. Merzlyakov ◽  
M.A. Yurlov
Keyword(s):  
Experimental Study ◽  
Cross Section ◽  
Nonlinear Effect ◽  
Cylindrical Specimen ◽  
Axial Stress ◽  
Circular Cross Section ◽  
Nonlinear Effects ◽  
Fixed Length ◽  
Oscillatory Component

The results of experiments related to torsion of uniform cylindrical specimen at the fixed length between the specimens ends are presented in this paper. Axial stress has been found, initially stretching and then compressing the sample which has an oscillatory component with the period of one turn. Reasons of this nonlinear effect that are not described in the references are discussed here.

scholarly journals Experimental Study on the Tensile Properties of Rock-Mortar Interface under Different Strain Rates

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Nan Wu ◽  
Zhende Zhu ◽  
Zhilei He
Keyword(s):  
Experimental Study ◽  
Tensile Strength ◽  
Strain Rate ◽  
Constitutive Relation ◽  
Crack Width ◽  
Axial Stress ◽  
Downward Trend ◽  
Crack Model ◽  
Strain Rates ◽  
Softening Function

In this paper, an experimental study was carried out on a rock-mortar interface specimen under three different strain rates (10−6, 10−5, and 10−4  s−1) using the MTS322 electrohydraulic servo loading system, and a new constitutive relation function of fictitious crack model (FCM) according to the axial-stress-crack-width curves of the rock-mortar interface is established, because the traditional nonlinear softening function easily distorts, shakes, and so cannot describe the damage-evolution process of the rock-mortar interface accurately. Through the use of a precise servo actuator system and three extensometers measured axial-stress-crack-width curves, it is shown that the rock-mortar interface is very sensitive to the strain rate. The tensile strength increases with strain rate, the crack width decreases at the same time, and the axial-stress-crack-width curves gradually evolve from a concave-downward trend to a linear decreasing trend. At the same time, the new constitutive relation function can reflect the tensile strength, crack width, and the downward trend of the rock-mortar interface more accurately.

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