scholarly journals Analysis of relation between edging ratio and deformation work done in pre-forming of workpiece by bulk buckling

2018 ◽  
Vol 178 ◽  
pp. 02003 ◽  
Author(s):  
Volodymyr Kukhar ◽  
Elena Balalayeva ◽  
Andrii Prysiazhnyi ◽  
Oleg Vasylevskyi ◽  
Iryna Marchenko
Keyword(s):  
Energy Efficient ◽  
Power Indices ◽  
Forming Process ◽  
Pressure Work ◽  
Similar Shape ◽  
Deformation Work ◽  
Work Of Deformation ◽  
Work Done

The results of studies of energy-power indices (contact face pressure, work of deformation) during upsetting with buckling of relatively high workpieces with upsetting ratio 3.5 to 6.0 are summarized in the paper. The relation between work of deformation at the bulk buckling and edging ratio, and similar shape ratios was established. The results are shown that buckling pass is an energy-efficient way of workpieces shaping for bent forgings or dual-forming of some products and belong to the class of dieless (impression-free) bulk pre-forming process.

Reply to Professor Simon’s comments

1952 ◽  
Vol 212 (1111) ◽  
pp. 477-477
Keyword(s):  
Free Energy ◽  
Potential Energy ◽  
Temperature Rise ◽  
Frictional Resistance ◽  
Mechanical Equivalent ◽  
Work Of Deformation ◽  
Work Done

The question raised by Professor Simon on the mechanism by which the work done against the frictional resistance is transformed into heat perhaps requires a more fundamental explanation than can be deduced from frictional experiments alone. I t is true that free energy is required for the formation of a new surface when the intermetallic junctions are ruptured, and this in itself does not produce an appreciable temperature rise. With plastic solids (as distinct from liquids), however, most of the work is required to deform the metal around the junctions. As Taylor & Quinney (1937) have shown at least 90% of the work of deformation is liberated as heat and less than 10 % remains as potential energy in the deformed metal, but if the metal is already heavily deformed the proportion of potential energy retained in the metal is negligibly small. Some of the early determinations of the mechanical equivalent of heat are of course based on the assumption that all the frictional work appears as heat. I would like to ask Dr A. J. W. Moore to comment further on this.

scholarly journals Canonical Transfer and Multiscale Energetics for Primitive and Quasigeostrophic Atmospheres

2016 ◽  
Vol 73 (11) ◽  
pp. 4439-4468 ◽  
Author(s):  
X. San Liang
Keyword(s):  
Multiple Scale ◽  
Pressure Work ◽  
The Past ◽  
Lie Bracket ◽  
Energy Transfers ◽  
Transport Kinetic ◽  
Work Done ◽  
Preliminary Application ◽  
Multiscale Window Transform ◽  
Canonical Transfer

Abstract The past years have seen the success of a novel and rigorous localized multiscale energetics formalism in a variety of ocean and engineering fluid applications. In a self-contained way, this study introduces it to the atmospheric dynamical diagnostics, with important theoretical updates and clarifications of some common misconceptions about multiscale energy. Multiscale equations are derived using a new analysis apparatus—namely, multiscale window transform—with respect to both the primitive equation and quasigeostrophic models. A reconstruction of the “atomic” energy fluxes on the multiple scale windows allows for a natural and unique separation of the in-scale transports and cross-scale transfers from the intertwined nonlinear processes. The resulting energy transfers bear a Lie bracket form, reminiscent of the Poisson bracket in Hamiltonian mechanics; hence, we would call them “canonical.” A canonical transfer process is a mere redistribution of energy among scale windows, without generating or destroying energy as a whole. By classification, a multiscale energetic cycle comprises available potential energy (APE) transport, kinetic energy (KE) transport, pressure work, buoyancy conversion, work done by external forcing and friction, and the cross-scale canonical transfers of APE and KE, which correspond respectively to the baroclinic and barotropic instabilities in geophysical fluid dynamics. A buoyancy conversion takes place in an individual window only, bridging the two types of energy, namely, KE and APE; it does not involve any processes among different scale windows and is hence basically not related to instabilities. This formalism is exemplified with a preliminary application to the study of the Madden–Julian oscillation.

On the Pressure Dependency of Physical Parameters in Case of Heat Transfer Problems of Supercritical Water

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Gabor Hazi ◽  
Istvan Farkas
Keyword(s):  
Heat Transfer ◽  
Supercritical Water ◽  
Physical Parameters ◽  
Convective Term ◽  
Pressure Work ◽  
Thermophysical Parameters ◽  
Pressure Dependency ◽  
Order Of Magnitude ◽  
Transfer Problems ◽  
Work Done

Studying heat transfer problems of supercritical water, the pressure dependency of thermophysical parameters (density, specific heat, viscosity, and thermal conductivity) and the work done by pressure are often neglected. Here we show that the variations of some physical parameters as functions of pressure have the same order of magnitude than their variations as functions of temperature in supercritical water. Therefore, pressure dependency of physical parameters should be taken into account in heat transfer calculations of supercritical water. It is also pointed out that the work done by pressure should not be neglected in supercritical water since the pressure work term has the same order of magnitude than the convective term near the pseudocritical temperature.

Recent advances and challenges in electroplastic manufacturing processing of metals

2010 ◽  
Vol 25 (7) ◽  
pp. 1215-1224 ◽  
Author(s):  
Lei Guan ◽  
Guoyi Tang ◽  
Paul K. Chu
Keyword(s):  
Microstructure Evolution ◽  
Metal Forming ◽  
Energy Efficient ◽  
Experimental Investigations ◽  
Forming Process ◽  
Electroplastic Effect ◽  
The Past ◽  
Current State ◽  
Recent Developments ◽  
Metal Forming Process

Electroplastic manufacturing processing (EPMP) is a relatively new metal-forming process that is energy efficient, environmentally friendly, and versatile. In particular, it can be used to manufacture metals or alloys that are difficult to process by conventional manufacturing protocols. There have been significant advances in EPMP in the past decade, and this review summarizes our current state of understanding and describes recent developments in EPMP. Particular emphasis is placed on describing the mechanisms responsible for the electroplastic effect and microstructure evolution as well as major advances in EPMP of metals. Challenges facing theoretical and experimental investigations are also discussed.

Energy-Efficient Solid Forward Extrusion through Hybridization Based on Process-Integrated Resistance Heating

2013 ◽  
Vol 554-557 ◽  
pp. 620-629 ◽  
Author(s):  
Michael Terhorst ◽  
Fritz Klocke ◽  
Stefan Niebes ◽  
Fabian Schongen ◽  
Patrick Mattfeld
Keyword(s):  
Energy Efficient ◽  
Process Integration ◽  
Numerical Algorithms ◽  
Numerical Approach ◽  
Extrusion Process ◽  
Resistance Heating ◽  
Forming Process ◽  
Workpiece Material ◽  
Forward Extrusion ◽  
Deform 2D

In this paper a hybridized solid forward extrusion process is proposed that uses a process-integrated resistance heating for the energy-efficient heating of the workpiece material in order to avoid the occurrence of chevron cracks. As for the process-integration of the resistance heating two variations are regarded: the preheating of the wrought material prior to the forming process as well as a resistance heating concurrent with the extrusion process. Based on a three-shouldered solid forward extrusion of Cf53 with emerging chevron cracks the broad temperature interval for crack elimination is derived from experiments where the wrought material is preheated in a furnace. With this derived temperature a numerical approach for the dimensioning of a resistance heating of both prior to the forming process and during extrusion is shown. The approach is based on solving the Fourier heat transfer equation using both numerical algorithms in MATLAB and finite element method (FEM) in Deform-2D. In a final step the two scenarios heating prior to and during the extrusion process are evaluated in terms of their energy-efficiency using FEM.

On the Pressure Dependency of Physical Parameters in Case of Heat Transfer Problems of Supercritical Water

2008 ◽  
Author(s):  
Gabor Hazi ◽  
Istvan Farkas
Keyword(s):  
Heat Transfer ◽  
Supercritical Water ◽  
Physical Parameters ◽  
Convective Term ◽  
Pressure Work ◽  
Thermophysical Parameters ◽  
Pressure Dependency ◽  
Order Of Magnitude ◽  
Transfer Problems ◽  
Work Done

Studying heat transfer problems of supercritical water, the pressure dependency of thermophysical parameters (density, specific heat, viscosity, thermal conductivity) and the work done by pressure are often neglected. Here we show that the variations of some physical parameters as functions of pressure have the same order of magnitude than their variations as functions of temperature in supercritical water. Therefore, pressure dependency of physical parameters should be taken into account in heat transfer calculations of supercritical water. It is also pointed out that the work done by pressure should not be neglected in supercritical water, since the pressure work term has the same order of magnitude than the convective term near the pseudocritical temperature.

Evaluation of metals deformability

2020 ◽  
pp. 243-246
Author(s):  
A.M. Nikonova ◽  
S.A. Barannikova
Keyword(s):  
Metal Forming ◽  
Deformation Behavior ◽  
Deformation Process ◽  
Strength Class ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Specific Work ◽  
Mechanical Processing ◽  
Deformation Work ◽  
Work Of Deformation

The laws of the deformation behavior of metals, determined by carrying out standardized uniaxial tensile tests are studied. The distribution of various strength class metals by strain resistance is analyzed. It is taken into account that in the thermodynamic aspect the deformation process is dissipative effect, therefore, the deformation work, determined by the area of the tension diagram, serves as basis for assessing of the metals deformability criteria. It is found that the normalized specific work of deformation increases linearly with increasing strength. In the applied aspect, the numerical values of the compliance criterion can be used to predict the behavior of various strength class materials during mechanical processing (metal forming and cutting) or operation.

Hydrostatic pressure on vagal effects and heart contraction

1962 ◽  
Vol 202 (5) ◽  
pp. 947-949 ◽  
Author(s):  
Wei Young ◽  
Frank Upham
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Inhibitory Effect ◽  
Inhibitory Effects ◽  
Pressure Work ◽  
Pressure Limit ◽  
Heart Contraction ◽  
Work Done ◽  
Kinetics Of ◽  
Definite Period

Vagal inhibitory effects are readily observed in isolated vagal heart preparations of Rana pipiens. The normal effect was partially blocked by raising the hydrostatic pressure to about 2,000 psi. There was a complete block of vagal effects at about 5,000 psi or more. When the preparation was subjected to low pressure, the vagal inhibitory effect again occurred. This process could be repeated several times. Physostigmine raised the critical pressure limit by about 2,000 psi. The observed phenomena are discussed in particular with respect to the kinetics of acetylcholinesterase under the high pressure. Work done per contraction of the heart is increased under high pressure by about 25%. The total work done, however, in a definite period, e.g., 1 min, is decreased because the rate of the contraction is decreased.

Finite Element Modeling of Superplastic Forming of Tubular Shapes

2010 ◽  
Vol 433 ◽  
pp. 179-184 ◽  
Author(s):  
Mohammed A. Nazzal ◽  
Fadi K. Abu-Farha
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Superplastic Forming ◽  
Forming Process ◽  
Tube Forming ◽  
Pressure Profiles ◽  
Significant Difference ◽  
Work Done

Most of the work done on superplastic forming is related to sheet metal forming. Very limited studies have been directed toward investigating the superplastic tube forming process. In this work, Finite Element (FE) simulations are carried out in order to simulate the superplastic tube forming process. The analysis is conducted for the superplastic magnesium alloy AZ31 at 400°C. The results clearly demonstrate that there is a significant difference between tube forming and sheet metal forming in terms of forming pressure profiles. In addition, the effects of tube radius, free forming length, and contact on the tube forming process are investigated.

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