Detection at a distance of laser-generated ultrasound using a confocal Fabry–Perot interferometer

1986 ◽  
Vol 64 (9) ◽  
pp. 1320-1323 ◽  
Author(s):  
Jean-Pierre Monchalin
Keyword(s):  
Laser Pulse ◽  
Doppler Shift ◽  
Steel Plate ◽  
Solid Sample ◽  
Experimental Results ◽  
Fabry Perot ◽  
Frequency Stabilized Laser

A novel scheme to detect ultrasonic motion at the surface of a solid sample is presented. The surface of the sample is illuminated by a frequency-stabilized laser and the light scattered by the surface is received by a confocal Fabry–Perot interferometer, which demodulates the Doppler shift produced by ultrasound. Experimental results, obtained at a distance of 1.5 m from a machined but not polished steel plate, and excited by ultrasound produced by a laser pulse, are presented.

scholarly journals Experimental/Numerical Evaluation of Steel Trapezoidal Corrugated Infill Panels with an Opening

2021 ◽  
Vol 11 (7) ◽  
pp. 3275
Author(s):  
Majid Yaseri Gilvaee ◽  
Massood Mofid
Keyword(s):  
Energy Dissipation ◽  
Ultimate Strength ◽  
Steel Plate ◽  
Shear Walls ◽  
Experimental Results ◽  
Structural Performance ◽  
Initial Stiffness ◽  
Infill Panels ◽  
Energy Dissipation Capacity ◽  
Ductility Ratio

This paper investigates the influence of an opening in the infill steel plate on the behavior of steel trapezoidal corrugated infill panels. Two specimens of steel trapezoidal corrugated shear walls were constructed and tested under cyclic loading. One specimen had a single rectangular opening, while the other one had two rectangular openings. In addition, the percentage of opening in both specimens was 18%. The initial stiffness, ultimate strength, ductility ratio and energy dissipation capacity of the two tested specimens are compared to a specimen without opening. The experimental results indicate that the existence of an opening has the greatest effect on the initial stiffness of the corrugated steel infill panels. In addition, the experimental results reveal that the structural performance of the specimen with two openings is improved in some areas compared to the specimen with one opening. To that end, the energy dissipation capacity of the specimen with two openings is obtained larger than the specimen with one opening. Furthermore, a number of numerical analyses were performed. The numerical results show that with increasing the thickness of the infill plate or using stiffeners around the opening, the ultimate strength of a corrugated steel infill panel with an opening can be equal to or even more than the ultimate strength of that panel without an opening.

scholarly journals A laser experiment for studying radiative shocks in astrophysics

2002 ◽  
Vol 20 (2) ◽  
pp. 263-268 ◽  
Author(s):  
X. FLEURY ◽  
S. BOUQUET ◽  
C. STEHLÉ ◽  
M. KOENIG ◽  
D. BATANI ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Pulse Duration ◽  
Experimental Results ◽  
Laboratory Astrophysics ◽  
Laser Pulse Duration ◽  
Radiative Shocks ◽  
Self Similar ◽  
Laser Experiment ◽  
Similar Solutions

In this article, we present a laboratory astrophysics experiment on radiative shocks and its interpretation using simple modelization. The experiment is performed with a 100-J laser (pulse duration of about 0.5 ns) which irradiates a 1-mm3 xenon gas-filled cell. Descriptions of both the experiment and the associated diagnostics are given. The apparition of a radiation precursor in the unshocked material is evidenced from interferometry diagrams. A model including self-similar solutions and numerical ones is derived and fairly good agreements are obtained between the theoretical and the experimental results.

Comparison of flexural capacity of different hollow slab beams with/without pavement layer reinforced by steel plates

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Long Liu ◽  
Lifeng Wang ◽  
Ziwang Xiao
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Steel Plate ◽  
Plate Thickness ◽  
Experimental Results ◽  
Nonlinear Material ◽  
Finite Element Models ◽  
Rc Beams ◽  
Flexural Capacity ◽  
Content Type

PurposeReinforcement of reinforced concrete (RC) beams in-service have always been an important research field, anchoring steel plate in the bottom of the beams is a kind of common reinforcement methods. In actual engineering, the contribution of pavement layer to the bearing capacity of RC beams is often ignored, which underestimates the bearing capacity and stiffness of RC beams to a certain extent. The purpose of this paper is to study the effect of pavement layer on the RC beams before and after reinforcement.Design/methodology/approachFirst, static load experiments are carried out on three in-service RC hollow slab beams, meanwhile, nonlinear finite element models are built to study the bearing capacity of them. The nonlinear material and shear slip effect of studs are considered in the models. Second, the finite element models are verified, and the numerical simulation results are in good agreement with the experimental results. Last, the finite element models are adopted to carry out the research on the influence of different steel plate thicknesses on the flexural bearing capacity and ductility.FindingsThe experimental results showed that pavement layers increase the flexural capacity of hollow slab beams by 16.7%, and contribute to increasing stiffness. Ductility ratio of SPRCB3 and PRCB2 was 30% and 24% lower than that of RCB1, respectively. The results showed that when the steel plate thickness was 1 mm–6 mm, the bearing capacity of the hollow slab beam increased gradually from 2158.0 kN.m to 2656.6 kN.m. As the steel plate thickness continuously increased to 8 mm, the ultimate bearing capacity increased to 2681.0 kN.m. The increased thickness did not cause difference to the bearing capacity, because of concrete crushing at the upper edge.Originality/valueIn this paper, based on the experimental study, the bearing capacity of hollow beam strengthened by steel plate with different thickness is extrapolated by finite element simulation, and its influence on ductility is discussed. This method not only guarantees the accuracy of the bearing capacity evaluation, but also does not require a large number of samples, and has certain economy. The research results provide a basis for the reinforcement design of similar bridges.

Investigation of the penetration resistance of monolithic and double-layered steel plates

2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940005
Author(s):  
Jie Cui ◽  
Xin Chen ◽  
Ali Tian ◽  
Renchuan Ye ◽  
Yanxi Qiao ◽  
...  
Keyword(s):  
Steel Plate ◽  
Penetration Resistance ◽  
Extensive Study ◽  
Experimental Results ◽  
Steel Plates ◽  
Layered Plates ◽  
Residual Velocity ◽  
Code Analysis ◽  
Calculation Results ◽  
Ballistic Limit Velocity

To analyze the influence of penetration resistance for different steel plate configurations, different steel plates impacted by various projectiles were studied using the LS-DYNA code. The calculation results obtained using the LS-DYNA code and prior experimental results reported in the literature agree well with the damaged image of projectiles penetrating steel plates and the initial residual velocity curve of the projectile. The Q235 steel constitutive model is modified based on the Johnson–Cook model. It can be concluded that the LS-DYNA code analysis is reliable when compared with the experimental results. We then used the LS-DYNA code to conduct an extensive study into the penetration resistance of monolithic, contact-type double-layered and gap-type double-layered targets with the same surface density, impacted by different projectiles. The failure mode of the steel plate, initial residual velocity, ballistic limit velocity, energy absorption and plastic deformation of the monolithic and double-layered plates were studied. The results in this paper can provide guidance for the design and application of structural protection using steel plates.

Fabry-Perot Velocimetry Techniques: Is Doppler Shift Affected By Surface Normal Direction?

1984 ◽  
Author(s):  
David R. Goosman ◽  
Alan M. Frank, ◽  
Henry H. Chau ◽  
Norval L. Parker
Keyword(s):  
Doppler Shift ◽  
Normal Direction ◽  
Surface Normal ◽  
Fabry Perot

KETAHANAN BALISTIK LEMBARAN BAJA PADA BERBAGAI SUDUT TEMBAK

ROTASI ◽  
2014 ◽  
Vol 16 (1) ◽  
pp. 34
Author(s):  
Rusnaldy Rusnaldy ◽  
Ismoyo Haryanto ◽  
Norman Iskandar ◽  
Binar Ade Anugra ◽  
Ahmad Zaedun
Keyword(s):  
Mild Steel ◽  
Steel Plate ◽  
Angle Of Attack ◽  
Oblique Impact ◽  
Experimental Results ◽  
Normal Impact ◽  
Impact Angles

Results of study on the performance of 0.4 mm mild steel plate when impacted by 4.5 mm diameter steel ogive-shaped projectile at 45o, 60o (oblique impact) and 90 o (normal impact) angles of attack are presented. The projectiles were fired at highest velocity using air riffle gun. The target-holding fixture was located at a distance of 2 m from the gun. Experimental results show that steel plate provides protection at 45o and 60o obliquity, but fails to provide protection at angle of attack of 90o (normal impact)

The LPL Radial Accelerometer

1984 ◽  
Vol 88 ◽  
pp. 63-86 ◽  
Author(s):  
R.S. McMillan ◽  
P.H. Smith ◽  
J.E. Frecker ◽  
W.J. Merline ◽  
M.L. Perry
Keyword(s):  
Optical Fiber ◽  
Radial Velocity ◽  
Doppler Shift ◽  
Focal Plane ◽  
Incident Light ◽  
The Sun ◽  
Stellar Spectrum ◽  
Entrance Aperture ◽  
Fabry Perot ◽  
Interference Order

AbstractWe have begun to observe radial velocities of stars with an optical spectrometer designed for unusually high accuracy. Light from a star image in the focal plane of a telescope is fed to the entrance aperture of the spectrometer by a single optical fiber. Wavelengths are calibrated by transmission of collimated light through a tilt-tunable Fabry-Perot interferometer. The scrambling of incident light rays by the optical fiber and the intrinsic stability of the Fabry-Perot etalon provide immunity to the sources of systematic errors that plague conventional radial velocity meters. The spectrum is dispersed by an echelle grating crossed with another plane reflection grating. Several echelle orders in the vicinity of 4250-4600 Å are imaged in a two-dimensional format on a charge-coupled (CCD) array of detectors. About 350 distinct points on the profile of the stellar spectrum are sampled by successive orders of interferometrie transmission through the etalon. In the vicinity of 4300 Å each interference order is 47 milliangstroms wide and the sample points are 0.64 Å apart, resulting in distinct , widely-spaced monochromatic images of the entrance aperture to be formed in the focal plane of the camera. Changes in Doppler shift cause changes in the relative intensities of these images, according to the slope of the spectral profile at each point sampled. The instrument is being operated as a null-measurement accelerometer, sensitive only to changes in radial velocity, which simplifies operation and enhances sensitivity. With an argon-filled, iron hollow cathode emission line lamp, the interferometer can be calibrated to two parts in 100 million; this corresponds to ± 6 meters/sec in Doppler shift. Calibrations of the interferometer show variations of ± 27 meters/sec on a time scale of months; observations of stars are corrected for such changes. The internal repeatability of observations of the differential Doppler shift of light from the integrated disk of the Sun is ± 6 meters/sec. The corresponding result from about 70 observations of Arcturus (Kl IIIb; B=1.19) is ± 40 meters/sec internal repeatability for each exposure of 20 square-meter seconds. The external repeatability (day-to-day differential accuracy) of nightly averages of stellar observations is ± 20 meters/second. Since the internal precision on the sun and the argon lamp is much better than it is with short exposures on Arcturus, the quality of our observations of stars is limited by the rate of detected photons. This justifies averaging a number of short exposures of a star to approach “laboratory” precision.

Experimental Results of Laser Wakefield Acceleration Using a Femtosecond Terawatt Laser Pulse

1999 ◽  
Vol 38 (Part 2, No. 8B) ◽  
pp. L967-L969 ◽  
Author(s):  
Masaki Kando ◽  
Hyeyoung Ahn ◽  
Hideki Dewa ◽  
Hideyuki Kotaki ◽  
Toru Ueda ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Experimental Results ◽  
Laser Wakefield Acceleration ◽  
Wakefield Acceleration ◽  
Laser Wakefield ◽  
Terawatt Laser

LIFETIME MEASUREMENTS IN 134Pr AND CHIRALITY IN NUCLEI

2006 ◽  
Vol 15 (07) ◽  
pp. 1531-1540 ◽  
Author(s):  
D. TONEV ◽  
P. PETKOV ◽  
D. L. BALABANSKI ◽  
G. DE ANGELIS ◽  
A. GADEA ◽  
...  
Keyword(s):  
Doppler Shift ◽  
Transition Probabilities ◽  
Experimental Results ◽  
Lifetime Measurements ◽  
Evaporation Reaction ◽  
Doppler Shift Attenuation ◽  
Recoil Distance ◽  
Reduced Transition Probabilities ◽  
Fusion Evaporation Reaction

Lifetimes of exited states in 134 Pr were measured be means of the recoil distance Doppler-shift and Doppler-shift attenuation techniques. The experiments were performed at IReS, Strasbourg using the EUROBALL IV spectrometer, in conjunction with the inner BGO ball and the Cologne coincidence plunger apparatus. Exited states in 134 Pr were populated in the fusion-evaporation reaction 119 Sn (19 F , 4 n )134 Pr . Reduced transition probabilities in 134 Pr are compared to the predictions of the two quasiparticle+triaxial rotor and interacting boson fermion-fermion models. The experimental results do not support the presence of static chirality in 134 Pr underlying the importance of shape fluctuations. Only within a dynamical context the presence of intrinsic chirality in 134 Pr can be supported.

Sign in / Sign up

Export Citation Format

Share Document