This article presents the results of a study on steel strip plasticization during straightening on roller straightening machines. The studies were conducted using the SIMULIA Abaqus finite element ...analysis system and with the implementation of an industrial experiment on straightening and plasma cutting of hot-rolled profile rolled stock. A significant effect of strip plasticization during straightening under conditions of alternating deformation on the deviation from the flatness of the profile rolled stock at high-tech processing is presented. The results confirmed that the minimum deviations of the strips from the flatness after cutting, not exceeding 2 mm, correspond to the straightening modes with a high plasticization of the strip at the beginning of straightening and the smallest at the end with the reduction of residual longitudinal stresses in thickness. The regression dependence of the strip plasticization on the main parameters of the straightening process based on the processing of a computational experiment was obtained, and its adequacy was established. Moreover, the parameters affecting the plasticization of the steel strip during straightening to a great extent are the number of rollers and difference in the vertical movements of the first and last rollers of the upper cassette.
The model developed for predicting the plasticization of a hot-rolled steel strip enables to develop recommendations for setting up roller machines to increase the impact on the shape of rolled products and evaluate the straightening process when designing and modernizing existing metal cross-cutting lines.
The final stage in the production of hot rolled steel is leveling on roller levelers under cyclic alternating deformation. When laser cuts a sheet, it may bend due to the release of residual stresses ...that are unevenly distributed over the volume. The majority of roller leveler models for calculating the process under cyclic alternating deformation does not provide an adequate assessment and prediction of residual stresses in a steel sheet. On the basis of finite element analysis, formation of residual stresses due to roller leveling of hot rolled strip is disclosed. The implementation of a leveling process model was performed in SIMULIA Abaqus. Models are verified by comparing forces under the rollers. We have experimentally confirmed the convergence of the simulation results with the measurements of the strip flatness obtained after sheets plasma cutting. It was found that after leveling, tensile longitudinal residual stresses remain on the upper surface of the sheet, compressive ones remain on the lower surface, stresses are zero in the middle in thickness, and the stress values are opposite in sign in the remaining parts of the section. It was established that the same parameters of the leveling process of different strength categories lead to different deviations of stresses. An increase in yield strength of the strip leads to an increase in the deviation of residual stresses along the strip thickness. The proposed method of simulation of roller leveling process should be used to study the stress-strain state of hot-rolled steel and to design improved strip leveling setting modes with minimal residual stress deviations.
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The review presents the experiments performed with the KEDR detector at the
collider VEPP-4M in the energy range of
= 1.84–3.88 GeV. The cross section of
annihilation to hadrons was measured at 22 ...points of this range and the search for narrow resonances was conducted below 3.1 GeV. The masses of
and
mesons were measured with a record accuracy better than
; their partial and total widths were determined. Measurements of the tau lepton mass and masses of charged and neutral
mesons were performed with high precision. The measurements of the
parameters are discussed, and attention is drawn to some inconsistency of the procedure employed by the Particle Data Group for determining its parameters.
Measurement of Γee(J/ψ) with KEDR detector Anashin, V. V; Aulchenko, V. M; Baldin, E. M ...
The journal of high energy physics,
05/2018, Letnik:
2018, Številka:
5
Journal Article
Recenzirano
Odprti dostop
A
bstract
The product of the electronic width of the
J/ψ
meson and the branching fractions of its decay to hadrons and electrons has been measured using the KEDR detector at the VEPP-4M
e
+
e
−
...collider. The obtained values are
Γ
e
e
J
/
ψ
=
5.550
±
0.056
±
0.089
keV
,
Γ
e
e
J
/
ψ
·
ℬ
hadrons
J
/
ψ
=
4.884
±
0.048
±
0.078
keV
,
Γ
e
e
J
/
ψ
·
ℬ
e
e
J
/
ψ
=
0.3331
±
0.0066
±
0.0040
keV
.
The uncertainties shown are statistical and systematic, respectively. Using the result presented and the world-average value of the electronic branching fraction, one obtains the total width of the
J/ψ
meson:
Γ
=
92.94
±
1.83
keV
.
These results are consistent with the previous experiments.
Using the KEDR detector at the VEPP-4M e+e− collider, we have determined the values of R at thirteen points of the center-of-mass energy between 1.84 and 3.05 GeV. The achieved accuracy is about or ...better than 3.9% at most of the energy points with a systematic uncertainty less than 2.4%.
Using the KEDR detector at the VEPP-4M e+e− collider, we have measured the values of Ruds and R at seven points of the center-of-mass energy between 3.12 and 3.72 GeV. The total achieved accuracy is ...about or better than 3.3% at most of energy points with a systematic uncertainty of about 2.1%. At the moment it is the most accurate measurement of R(s) in this energy range.
Total Energy Control of Aircraft Longitudinal Motion Belokon, S. A.; Zolotukhin, Yu. N.; Kotov, K. Yu ...
Optoelectronics, instrumentation, and data processing,
10/2023, Letnik:
59, Številka:
5
Journal Article
Recenzirano
The paper considers the creation of a system for controlling the longitudinal motion of aircraft based on the principle of total energy control. The structure of the control system is presented, ...including a kernel independent of aircraft and a transition to commands for elevator and thrust deflection obtained from the principle of inverse models. The control system is implemented for models of three aircraft with different aerodynamic configurations. The quality of regulation was studied by numerical simulation.
The present work continues a series of the KEDR measurements of the R value that started in 2010 at the VEPP-4M e+e− collider. By combining new data with our previous results in this energy range we ...measured the values of Ruds and R at nine center-of-mass energies between 3.08 and 3.72 GeV. The total accuracy is about or better than 2.6% at most of energy points with a systematic uncertainty of about 1.9%. Together with the previous precise R measurement at KEDR in the energy range 1.84–3.05 GeV, it constitutes the most detailed high-precision R measurement near the charmonium production threshold.
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