scholarly journals Numerical Model Simulation of the Double-Roll Rotary Forging of Large Diameter Thin-Walled Disk

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1767
Author(s):  
Zhongquan Yu ◽  
Mingchao Chen ◽  
Chong Ma ◽  
Site Luo ◽  
Chundong Zhu
Keyword(s):  
Numerical Model ◽  
Model Simulation ◽  
High Surface ◽  
Large Diameter ◽  
Metal Flow ◽  
Deformation Characteristic ◽  
Low Noise ◽  
Forging Process ◽  
Rotary Forging ◽  
Thin Walled

Double-roll rotary forging is an emerging plastic forming technology based on rotary forging. Owing to the advantages of being labor-saving, a small eccentric load, low noise and vibration, good uniformity, high surface quality, and material saving, it is very promising for the fabrication of large diameter thin-walled disks. To date, little relevant research on the double-roll rotary forging technology of large diameter thin-walled metal disks has been reported, and the deformation characteristic and the influence of three key parameters on the double-roll rotary forging process remain uninvestigated. Herein, a reasonable 3D rigid-plastic numerical model of the double-roll rotary forging of a disk workpiece is established under the Deform software environment. Based on the valid 3D numerical model, the deformation mechanism, and the effective laws of three key parameters (feed rate v of the lower die, rotational speed n of the upper die, and the initial temperature T of the disk workpiece) on the metal flow and force and power parameters in the double-roll rotary forging process have been explored. The research results provide valuable guidelines for a better understanding of double-roll rotary forging for the fabrication of large diameter thin-walled disks.

scholarly journals Forming Characteristics and Mechanism of Double-roll Rotary forging for Large Diameter and Thin-walled Metal Discs

2021 ◽  
Author(s):  
Zhongquan Yu ◽  
Chundong Zhu ◽  
Mingchao Chen ◽  
Site Luo
Keyword(s):  
High Surface ◽  
Large Diameter ◽  
Equivalent Stress ◽  
Low Noise ◽  
Forming Process ◽  
Eccentric Load ◽  
Geometric Shapes ◽  
Rotary Forging ◽  
Forming Characteristics ◽  
Thin Walled

Abstract Double-roll rotary forging is an emerging plastic forming technology based on rotary forging. Owing to the advantages of labor saving, small eccentric load, low noise and vibration, good uniformity, high surface quality and material saving, it is very promising for fabrication of large-diameter thin-walled disc. To date, few relevant research on the double-roll rotary forging technology of large-diameter thin-walled metal discs has been reported, and the forming mechanisms and process of disc workpieces remains uninvestigated. Herein, a 3D rigid-plastic finite element model (FEM) is established to simulate the fabrication process of large-diameter thin-walled disc, four geometric features appear in the forming process: “mushroom” shape, “upper drum” shape, “drum shape” shape and “lower drum” shape. Equivalent stress, equivalent strain and temperature field of these four geometric shapes are analyzed, and the forming mechanism of these four geometric shapes is revealed. The reliability and accuracy of FEM are verified through experiments and the four geometric shape features occur in the process are consistent with the simulation. The research results provide valuable guidelines for better understanding of double-roll rotary forging for the fabrication of large-diameter thin-walled discs.

scholarly journals Dynamic Impedances of Offshore Rock-Socketed Monopiles

2019 ◽  
Vol 7 (5) ◽  
pp. 134 ◽  
Author(s):  
Rui He ◽  
Ji Ji ◽  
Jisheng Zhang ◽  
Wei Peng ◽  
Zufeng Sun ◽  
...  
Keyword(s):  
Numerical Model ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Dynamic Stiffness ◽  
Large Diameter ◽  
Offshore Wind ◽  
Offshore Wind Turbines ◽  
Thin Walled ◽  
Rock Parameters ◽  
Radiative Damping

With the development of offshore wind energy in China, more and more offshore wind turbines are being constructed in rock-based sea areas. However, the large diameter and thin-walled steel rock-socketed monopiles are very scarce at present, and both the construction and design are very difficult. For the design, the dynamic safety during the whole lifetime of the wind turbine is difficult to guarantee. Dynamic safety of a turbine is mostly controlled by the dynamic impedances of the rock-socketed monopile, which are still not well understood. How to choose the appropriate impedances of the socketed monopiles so that the wind turbines will neither resonant nor be too conservative is the main problem. Based on a numerical model in this study, the accurate impedances are obtained for different frequencies of excitation, different soil and rock parameters, and different rock-socketed lengths. The dynamic stiffness of monopile increases, while the radiative damping decreases as rock-socketed depth increases. When the weathering degree of rock increases, the dynamic stiffness of the monopile decreases, while the radiative damping increases.

Fractality of Simulated Fracture

2009 ◽  
Vol 409 ◽  
pp. 154-160 ◽  
Author(s):  
Petr Frantík ◽  
Zbyněk Keršner ◽  
Václav Veselý ◽  
Ladislav Řoutil
Keyword(s):  
Numerical Model ◽  
Elastic Plate ◽  
Model Simulation ◽  
Element Model ◽  
The Other ◽  
Particle Model ◽  
Discrete Element Model ◽  
Fractal Nature ◽  
Discrete Elements ◽  
The Impact

The paper is focussed on numerical simulations of the fracture of a quasi-brittle specimen due to its impact onto a fixed rigid elastic plate. The failure of the specimen after the impact is modelled in two ways based on the physical discretization of continuum: via physical discrete elements and pseudo-particles. Advantages and drawbacks of both used methods are discussed. The size distribution of the fragments of the broken specimen resulting from physical discrete element model simulation follows a power law, which indicates the ability of the numerical model to identify the fractal nature of the fracture. The pseudo-particle model, on the other side, can successfully predict the kinematics of the fragments of the specimen under impact failure.

scholarly journals Evaluation of stresses in large diameter, thin walled piping at support locations

1992 ◽  
Author(s):  
B.J. Bryan ◽  
H.E. Jr. Flanders ◽  
G.B. Jr. Rawls
Keyword(s):  
Large Diameter ◽  
Thin Walled

scholarly journals Free oscillations of thin-walled bimetallic pipelines of large diameter on an elastic foundation

2018 ◽  
Vol 193 ◽  
pp. 02027
Author(s):  
Vladimir Sokolov ◽  
Igor Razov ◽  
Evgeniy Koynov
Keyword(s):  
Elastic Foundation ◽  
Nuclear Power ◽  
Large Diameter ◽  
Compressive Force ◽  
Free Oscillations ◽  
Working Pressure ◽  
Momentum Theory ◽  
Internal Working ◽  
Nonlinear Version ◽  
Thin Walled

In the article, solutions are obtained for a thin-walled bimetallic pipeline. Solutions are obtained, and the frequencies of free oscillations are investigated taking into account the internal working pressure, the longitudinal compressive force, and the elastic foundation. The solutions were obtained on the basis of a geometrically nonlinear version of the semi-momentum theory of cylindrical shells of the middle bend. The proposed calculations can find application in the nuclear power industry, aviation, and the petrochemical industry.

On the Origin of Rotation Derived from Super Rapid Scan Satellite Imagery at the Cloud-Tops of Severe Deep Convection

2021 ◽  
Author(s):  
Jason M. Apke ◽  
John R. Mecikalski
Keyword(s):  
Quality Control ◽  
Numerical Model ◽  
Flow Field ◽  
Optical Flow ◽  
Case Studies ◽  
Model Simulation ◽  
Deep Convection ◽  
Vertical Wind Shear ◽  
Future Research ◽  
Severe Thunderstorms

AbstractSevere thunderstorms routinely exhibit adjacent maxima and minima in cloud-top vertical vorticity (CTV) downstream of overshooting tops within flow fields retrieved using sequences of fine-temporal resolution (1-min) geostationary operational environmental satellite (GOES)-R series imagery. Little is known about the origin of this so-called “CTV couplet” signature, and whether the signature is the result of flow field derivational artifacts. Thus, the CTV signature’s relevance to research and operations is currently ambiguous. Within this study, we explore the origin of near-cloud-top rotation using an idealized supercell numerical model simulation. Employing an advanced dense optical flow algorithm, image stereoscopy, and numerical model background wind approximations, the artifacts common with cloud-top flow field derivation are removed from two supercell case studies sampled by GOES-R imagers. It is demonstrated that the CTV couplet originates from tilted and converged horizontal vorticity that is baroclinically generated in the upper levels (above 10 km) immediately downstream of the overshooting top. This baroclinic generation would not be possible without a strong and sustained updraft, implying an indirect relationship to rotationally-maintained supercells. Furthermore, it is demonstrated that CTV couplets derived with optical flow algorithms originate from actual rotation within the storm anvils in the case studies explored here, though supercells with opaque above anvil cirrus plumes and strong anvil-level negative vertical wind shear may produce rotation signals as an artifact without quality control. Artifact identification and quality control is discussed further here for future research and operations use.

Study on Cylindrical Heatsink Forging Process Considering Friction Condition

2019 ◽  
Vol 823 ◽  
pp. 141-144
Author(s):  
Tung Sheng Yang ◽  
Yong Nan Chen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Friction Factor ◽  
Testing Machine ◽  
Metal Flow ◽  
Compression Tests ◽  
Stress Strain ◽  
Element Analysis ◽  
Forging Process ◽  
Different Temperatures

The feasibility of forging of AL-1050 alloy of cylindrical heatsink under warm conditions is demonstrated in the present work. The stress-strain curves and friction factor play an important role in the cylindrical heatsink forging. The purpose of forging lubrication is to reduce friction between blank and die, and to decrease resistance of metal flow to die. The stress-strain curves at different temperatures are obtained by compressing tests. The friction factor between 1050 aluminum alloy and die material are determined at different temperatures by ring compression tests with graphite lubricants. The compressing and ring compressing tests are carried out by using the computerized screw universal testing machine. The finite element method is used to investigate the forming characters of the forging process. To verify the prediction of FEM simulation in the cylindrical heatsink forging process, the experimental parameters such as stress-strain curves and fiction factor, are as the input data during analysis. Maximum forging load and effective stress distribution are determined of the heatsink forging, using the finite element analysis. Finally, the cylindrical heatsink parts are formed by the forging machine under the conditions using finite element analysis.

A FEA Simulation Model for Thin-Walled C-Section Composite Beam Assembling With R-Angle Deviation

2014 ◽  
Author(s):  
Hua Wang ◽  
Suo Si
Keyword(s):  
Numerical Model ◽  
Composite Beam ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Element Model ◽  
Load Level ◽  
Compression Tests ◽  
Accurate Analysis ◽  
Angle Deviation ◽  
Thin Walled

There are unavoidable deviations, such as shrinkage and distortions, in the composite detail parts production due to the complexity of composites fabrication. Interests in the assembly analysis of composite beams have led to a need for more accurate analysis especially in the case of fabrication deviations. This work proposes a numerical finite element model of thin-walled C-section composite beam with R-angle deviation for assembling. The rule of Hashin failure combined with cohesive element is applied to study the mechanical performance of the fiber and matrix (implemented as user subroutine UMAT in ABAQUS) while positioning and clamping. Tension and compression tests are carried out based on available standards to determine the C-section beam behavior under load. The testing data validates the proposed numerical model. The numerical model captures the experimentally obtained results with minimal error, and predicts the failure modes successfully. The proposed model allows to determine accurately the first failure location and the associated load level. It will enhance the understanding of the composite components pre-loading analysis, and help systematically improving the composites assembling efficiency in civil aircraft industry.

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