scholarly journals The Effect of Forging Conditions on Final Macrostructure of Slab Ingot from the 55NiCrMoV7 Tool Steel

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 435
Author(s):  
Petr Jonšta ◽  
Vladislav Kurka ◽  
Marek Vindyš ◽  
Ladislav Kander
Keyword(s):  
Numerical Simulation ◽  
Numerical Modelling ◽  
Numerical Simulations ◽  
Cross Section ◽  
Tool Steel ◽  
Forging Ingot ◽  
Steel Forging ◽  
Polygonal Shape ◽  
The Cross ◽  
Plate Type

The paper presents numerical modelling and an operational experiment to forge a slab ingot P40N from 55NiCrMoV7 tool steel and the procedure for the optimization of its production. The aim of the numerical simulation of forging was to verify the existing procedure of forging a plate from a conventional polygonal 8K forging ingot and a slab ingot with a polygonal shape of P40N surfaces. The effect of the shape of the ingot on the achievement of the required forging reduction and strain after the cross section of the forging of the plate, with final dimensions of approximately 1010 mm width × 310 mm thickness × 5350 mm length, was studied. The results obtained in the operational experiment showed satisfactory qualitative parameters of the steel forging from the slab P40N ingot which were in accordance with the predicted results of numerical simulations. The results indicated that in selected cases the use of a slab P40N ingot instead of the conventional polygonal 8K forging ingot can be considered in the production of certain plate-type forgings.

scholarly journals Discussion on the Theoretical Basis for Cross-Over Method Applied to Downhole Wave Velocity Test

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Qing Dong ◽  
Zheng-hua Zhou ◽  
Su Jie ◽  
Bing Hao ◽  
Yuan-dong Li
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Wave Velocity ◽  
Theoretical Basis ◽  
Influence Factors ◽  
P Wave ◽  
Engineering Practice ◽  
S Wave ◽  
Simulation Results ◽  
The Cross

At engineering practice, the theoretical basis for the cross-over method, used to obtain shear wave arrival time in the downhole method of the wave velocity test by surface forward and backward strike, is that the polarity of P-wave keeps the same, while the polarity of S-wave transforms when the direction of strike inverted. However, the characteristics of signals recorded in tests are often found to conflict with this theoretical basis for the cross-over method, namely, the polarity of the P-wave also transforms under the action of surface forward and backward strike. Therefore, 3D finite element numerical simulations were conducted to study the validity of the theoretical basis for the cross-over method. The results show that both shear and compression waves are observed to be in 180° phase difference between horizontal signal traces, consistent with the direction of excitation generated by reversed impulse. Furthermore, numerical simulation results prove to be reliable by the analytic solution; it shows that the theoretical basis for the cross-over method applied to the downhole wave velocity test is improper. In meanwhile, numerical simulations reveal the factors (inclining excitation, geophone deflection, inclination, and background noise) that may cause the polarity of the P-wave not to reverse under surface forward and backward strike. Then, as to reduce the influence factors, we propose a method for the downhole wave velocity test under surface strike, the time difference of arrival is based between source peak and response peak, and numerical simulation results show that the S-wave velocity by this method is close to the theoretical S-wave velocity of soil.

Numerical Simulation of Atmospheric Flow Field around Bridge

2013 ◽  
Vol 368-370 ◽  
pp. 1379-1382
Author(s):  
Ying Jia ◽  
Li Zhang ◽  
Sheng Zhang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Pressure Distribution ◽  
Cross Section ◽  
Horizontal Plane ◽  
Atmospheric Flow ◽  
Airflow Field ◽  
Distribution Laws ◽  
The Cross

This paper carries out a numerical simulation of the atmospheric flow field around bridge. The variation law of airflow field around bridge is studied. Velocity and pressure distribution laws of flow field in horizontal plane and the cross-section are discussed, and influence range of flow field around bridge area is identified.

Numerical Simulation on Temperature Field of CFST Member under Solar Radiation

2011 ◽  
Vol 354-355 ◽  
pp. 1241-1244
Author(s):  
Yan He ◽  
Man Ding ◽  
Qian Zhang
Keyword(s):  
Numerical Simulation ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Solar Radiation ◽  
Cross Section ◽  
Temperature Difference ◽  
Steel Tube ◽  
Concrete Filled Steel Tube ◽  
Nonlinear Temperature ◽  
The Cross

In this paper the temperature field of Concrete Filled Steel Tube (CFST) member under solar radiation is simulated. The results show that temperature distribution caused by solar radiation is nonlinear over the cross-section of CFST member, and it is significantly varied with time and sections, the largest nonlinear temperature difference is over 26.3°C.

scholarly journals Numerical simulation of cutting layer in internal corners milling

Mechanik ◽  
2019 ◽  
Vol 92 (7) ◽  
pp. 412-414
Author(s):  
Jan Burek ◽  
Rafał Flejszar ◽  
Barbara Jamuła
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Cross Section ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Cross Section Area ◽  
Section Area ◽  
The Cross ◽  
The Stability

The analytical and numerical model of the cross-section of the machined layer in the process of milling of concave rounding is presented. Simulation tests were carried out to determine the cross-sectional area of the cutting layer. A strategy has been developed that allows to increase the stability of the cross-section area of the cutting layer when the mill enters the inner corner area.

scholarly journals Numerical simulation of the transverse flow over spans of girder bridges

2018 ◽  
Vol 18 (4) ◽  
pp. 362-378
Author(s):  
Yu. A. Gosteev ◽  
A. D. Obukhovskiy ◽  
S. D. Salenko
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Cross Section ◽  
Cross Sections ◽  
Aerodynamic Characteristics ◽  
Transverse Flow ◽  
Single Beam ◽  
Weighted Estimates ◽  
Girder Bridges ◽  
The Cross

Introduction. The technique of numerical modeling of the transverse flow over span structures of bridges on the basis of the two-dimensional URANS (Unsteady Reynolds-averaged Navier-Stokes) approach used in the modern methods and software packages for computational fluid dynamics is verified. The work objective was debugging and experimental substantiation of this technique with the use of the database on the aerodynamic characteristics of the cross-sections of span structures of girder bridges of standard shapes pre-developed by the authors.Materials and Methods. A numerical simulation of the transverse flow of low-turbulent (smooth) and turbulent air flows around the bridge structures in a range of practically interesting attack angles is carried out. SST  k − ω turbulence model was used as the closing one. The technique was preliminarily tested on the check problem for the flow of the rectangular crosssection beams. Calculations were carried out using the licensed ANSYS software.Research Results. The calculated dependences on the attack angle of the aerodynamic coefficients of forces (drag and lift) and the moment of the cross sections of the girder bridges of standard shapes are obtained. These data refer to the span structures at the construction phase (without deck and parapets, without parapets) and operation phase, under the conditions of model smooth and turbulent incoming flow. The latter allows us to outline the boundaries for more weighted estimates of the aerodynamic characteristics of thegirder bridges in a real wind current. The best agreement with the experimental data was obtained from the drag of the cross-section. The magnitude of the lifting force is more sensitive to the presence and extent of the separation regions, so its numerical determination is less accurate. The reproduction of the angle-of-attack effect on the aerodynamic moment of the cross-section is the most challenging for the majority of configurations.Discussion and Conclusions. Comparison of the calculated and experimental data indicates the applicability of the URANS approach to the operational prediction of the aerodynamic characteristics of the single-beam span structures. In the case of multi-beam span structures, where the aerodynamic interference between separate girders plays an important role, the URANS approach must apparently give way to more accurate eddy-resolving methods. The results obtained can be used in the aerodynamic analysis of structures and in practice of the relevant design organizations in the field of transport construction.

Influence of Courtyard Size on Stack Effect During Building Fires

2021 ◽  
Vol 13 (6) ◽  
Author(s):  
Yanqiu Chen ◽  
Qianhang Feng ◽  
Xiankun Wang ◽  
Junmin Chen
Keyword(s):  
Numerical Simulations ◽  
Cross Section ◽  
Fire Protection ◽  
Pressure Difference ◽  
Three Dimensional ◽  
Building Fires ◽  
Stack Effect ◽  
Fire Smoke ◽  
The Cross

Abstract This paper studied the stack effect in courtyards in buildings through the pressure difference between the top and the bottom in the courtyard through three-dimensional (3D) numerical simulations, which would provide engineering guidance for the fire protection design of courtyards in buildings. During the fire, the stronger the stack effect was, the pressure difference between the top and the bottom was more significant, the fire smoke reached the top of the courtyard more quickly, and the temperature and the smoke concentration at the top were influenced in a shorter time. The influence of the size of the courtyard in the stack effect was investigated. It was found that the stack effect was linearly negatively related to the width of the cross section W and the length of the cross section L, exponentially negatively related with the area of the cross section A, while it was exponentially positively related to the height of the courtyard H. The change in the walls without windows (W) affected ΔPmax and the stack effect more significantly compared with the change in walls with windows (L). When L/W ≤ 1, the stack effect was strengthened as L/W increased; when L/W > 1, the stack effect was weakened as L/W increased. The stack effect was the most significant when L/W = 1.

Prediction of Carbon Liquation in Steel Forging Ingot Cross Section

Metallurgist ◽  
2016 ◽  
Vol 60 (7-8) ◽  
pp. 786-801 ◽  
Author(s):  
A. N. Romashkin ◽  
V. S. Dub ◽  
D. S. Tolstykh ◽  
I. A. Ivanov ◽  
A. N. Mal’ginov
Keyword(s):  
Cross Section ◽  
Forging Ingot ◽  
Steel Forging

Resonance in Flow-Induced Cable Vibration: Analytical Prediction and Numerical Simulation

2005 ◽  
Author(s):  
M. K. Kwan ◽  
R. R. Hwang ◽  
C. T. Hsu
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Cross Section ◽  
Flow Direction ◽  
Cross Flow ◽  
Transverse Cross Section ◽  
Analytical Prediction ◽  
Water Flows ◽  
Flow Displacement ◽  
The Cross

Flow-induced resonance for a two-end hinged cable under uniform incoming flows is investigated using analytical prediction and numerical simulation. In this study, the fundamental mode is analyzed for simplicity. First, based on a series of physical judgments, the approximate cable trajectory is predicted — the whole cable vibrates as a standing wave, with its locus on the transverse cross-section having a convex “8”-like shape. To find the exact path, however, experiment or numerical simulation is necessary. Hence, a bronze cable at aspect ratio (length/diameter) of 100 under water flows at Reynolds number (based on cable diameter and incoming velocity) of 200 is computed. The result confirms our predictions. Moreover, it is found that the amplitude of the cross-flow displacement is much higher than that of the streamwise displacement, despite the higher streamwise fluid force. As a consequence, energy transfer from fluid to solid is maximized in the cross-flow direction.

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