Prediction of Heat Distribution Shape and Nozzle Diameter of Plasma Arc Cutter

2011 ◽  
Vol 284-286 ◽  
pp. 2465-2468
Author(s):  
Aniruddha Ghosh ◽  
Shailendra Bhatia ◽  
Somnath Chattopadhyaya
Keyword(s):  
Aerodynamic Drag ◽  
Three Dimensional ◽  
Distribution Model ◽  
Work Piece ◽  
Heat Distribution ◽  
Plasma Arc ◽  
Plasma Properties ◽  
Plasma Torches ◽  
Distribution Shape ◽  
Energy And Momentum

Theoretical three-dimensional Gaussian heat distribution model of the complex heat flow and plasma properties of cutting plasma torches have been developed. For cutting metallic plates, plasma torches must produce a narrow supersonic plasma jet with enough energy and momentum densities to melt, vaporize, and remove the metal from the impingement region. Our model allows us to study the details of the heat distribution and to make predictions on pick temperature development on metal surface, heat transfer to the work piece, force i.e. the forces acting on the melt (aerodynamic drag, gravity, viscosity and surface tension) during plasma arc cutting, the main forces acting on the melt is believed to be the aerodynamic drag force and the gravity is significant only for thick metal plates. With the help of these assumptions and diameter of Gaussian heat source’s volume, diameter of nozzle has been calculated for thin work piece. A good agreement is found between the model results and the available experimental data.

Simulation of Three-Dimensional Stress Distribution in Compression Dies

2008 ◽  
Vol 575-578 ◽  
pp. 449-454
Author(s):  
Chu Yun Huang ◽  
Sai Yu Wang ◽  
Tao Yang ◽  
Xu Dong Yan
Keyword(s):  
Stress Distribution ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Distribution Model ◽  
Extrusion Dies ◽  
Maximum Value ◽  
Multiple Unit ◽  
Stress Freezing Method ◽  
Experimental Values ◽  
Aided Design

The stress fields of rectangular and T shape compression dies were simulated by three dimensional photo-elasticity of stress freezing method. The rules of stress distribution of σx, σy, σz on the surface of rectangular and T-shaped dies were discovered, and the rules were also found inside the dies. The results indicate that the stress distribution of rectangular die is similar to that of T shape die. Obvious stress concentration in corner of die hole was observed. σz rises from die hole to periphery until it achieves maximum value then it diminishes gradually, and σz between die hole and fix diameter zone is higher than it is in other position. At the same time, the equations of stress field of extrusion dies were obtained by curved surface fitting experimental values in every observed point with multiple-unit regression analysis method and orthogonal transforms. These works can provide stress distribution model for die computer aided design and make.

Energy and Momentum Eigenspectrum of the Hulthén-screened Cosine Kratzer Potential Using Proper Quantization Rule and SUSYQM Method

2021 ◽  
Author(s):  
Kaushal R Purohit ◽  
Rajendrasinh H PARMAR ◽  
Ajay Kumar Rai
Keyword(s):  
Quantum Mechanics ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Numerical Data ◽  
Time Dependent ◽  
Quantization Rule ◽  
Approximation Approach ◽  
Momentum Spectra ◽  
Energy And Momentum ◽  
Three Dimensional Space

Abstract Using the Qiang-Dong proper quantization rule (PQR) and the supersymmetric quantum mechanics approach, we obtained the eigenspectrum of the energy and momentum for time independent and time dependent Hulthen-screened cosine Kratzer potentials. For the suggested time independent Hulthen-screened cosine Kratzer potential, we solved the Schrodinger equation in D dimensions (HSCKP). The Feinberg-Horodecki equation for time-dependent Hulthen-screened cosine Kratzer potential was also solved (tHSCKP). To address the inverse square term in the time independent and time dependent equations, we employed the Greene-Aldrich approximation approach. We were able to extract time independent and time dependent potentials, as well as their accompanying energy and momentum spectra. In three-dimensional space, we estimated the rotational vibrational (RV) energy spectrum for many homodimers ($H_2, I_2, O_2$) and heterodimers ($MnH, ScN, LiH, HCl$). We also used the recently introduced formula approach to obtain the relevant eigen function. We also calculated momentum spectra for the dimers $MnH$ and $ScN$. The method is compared to prior methodologies for accuracy and validity using numerical data for heterodimer $LiH, HCl$ and homodimer $I_2, O_2,H_2$. The calculated energy and momentum spectra are tabulated and analysed.

A Three-Dimensional Load Sharing Model of Planetary Gear Sets Having Manufacturing Errors

2015 ◽  
Author(s):  
Nicholas D. Leque ◽  
Ahmet Kahraman
Keyword(s):  
Three Dimensional ◽  
Planetary Gear ◽  
Load Sharing ◽  
Distribution Model ◽  
Gear Mesh ◽  
Position Errors ◽  
Proposed Model ◽  
Manufacturing Errors ◽  
Manufacturing Tolerancing ◽  
Planetary Gear Sets

Planet-to-planet load sharing is a major design and manufacturing tolerancing issue in planetary gear sets. Planetary gear sets are advantageous over their countershaft alternatives in many aspects, provided that each planet branch carries a reasonable, preferably equal, share of the torque transmitted. In practice, the load shared among the planets is typically not equal due to the presence of various manufacturing errors. This study aims at enhancing the models for planet load sharing through a three-dimensional formulation of N-planet helical planetary gear sets. Apart from previous models, the proposed model employs a gear mesh load distribution model to capture load and time dependency of the gear meshes iteratively. It includes all three types of manufacturing errors, namely constant errors such as planet pinhole position errors and pinhole diameter errors, constant but assembly dependent errors such as nominal planet tooth thickness errors, planet bore diameter errors, and rotation and assembly dependent errors such as gear eccentricities and run-outs. At the end, the model is used to show combined influence of these errors on planet load sharing to aid designers on how to account for manufacturing tolerances in the design of the gears of a planetary gear set.

scholarly journals Ultra-small MOSFETs: The Importance of the Full Coulomb Interaction on Device Characteristics

VLSI Design ◽  
2001 ◽  
Vol 13 (1-4) ◽  
pp. 75-78 ◽  
Author(s):  
W. J. Gross ◽  
D. Vasileska ◽  
D. K. Ferry
Keyword(s):  
Coulomb Interaction ◽  
Short Range ◽  
Three Dimensional ◽  
Real Space ◽  
Relaxation Processes ◽  
Dimensional Model ◽  
Impurity Effects ◽  
Three Dimensional Model ◽  
Momentum Relaxation ◽  
Energy And Momentum

We discuss a full three-dimensional model of an ultra-small MOSFET, in which the transport is treated by a coupled EMC and molecular dynamics (MD) procedure to treat the Coulomb interaction in real space. The inclusion of the proper Coulomb interaction affects both the energy and momentum relaxation processes, but also has a dramatic effect on the characteristic curves of the device. We find that the short-range e–e and e–i terms, combined with discrete impurity effects, is also needed for accurate measurement of the device threshold voltage.

Differentiation of Gliomas Using Tissue Parameters and a Three-dimensional Density Distribution Model

1990 ◽  
pp. 294-298
Author(s):  
P. Pedrosa ◽  
M. Jungke ◽  
M. Grigat ◽  
H. P. Higer ◽  
S. Meindl ◽  
...  
Keyword(s):  
Density Distribution ◽  
Three Dimensional ◽  
Distribution Model

scholarly journals A Semi-Analytical Load Distribution Model for Cycloid Drives with Tooth Profile and Longitudinal Modifications

2020 ◽  
Vol 10 (14) ◽  
pp. 4859
Author(s):  
Ting Zhang ◽  
Xuan Li ◽  
Yawen Wang ◽  
Lining Sun
Keyword(s):  
Load Distribution ◽  
Contact Stiffness ◽  
Three Dimensional ◽  
Elastic Half Space ◽  
Distribution Model ◽  
Influence Coefficient ◽  
Hertz Contact ◽  
Tooth Contact Analysis ◽  
Tooth Contact ◽  
Analysis And Design

The current load distribution model for cycloid drives based on the Hertz contact stiffness typically assumes a two-dimensional planar problem without considering the tooth longitudinal modification effects, which fails to comply with the practical situation. In this paper, this issue is clarified by developing a semi-analytical load distribution model based on a three-dimensional and linear elastic solution. Unloaded tooth contact analysis is introduced to determine the instantaneous mesh information. The tooth compliance model considering tooth contact deformation is established by combining the Boussinesq force–displacement relationships in elastic half-space with an influence coefficient method. With this, the loads, contact patterns, and loaded transmission error are calculated by enforcing the compatibility and equilibrium conditions. Comparisons to predictions made with the assumption of Hertz contact stiffness are presented to demonstrate the effectiveness of the proposed model, which shows good agreement. At the end, the effect of tooth longitudinal modifications on load distributions is investigated along with various loading conditions. This study yields an in-depth understanding of the multi-tooth contact characteristics of cycloid drives and provides an effective tool for extensive parameter sensitivity analysis and design optimization studies.

Numerical Simulation of the Relation between Plasma Reflection and Keyhole Dimension in the Keyhole PAW Process

2011 ◽  
Vol 399-401 ◽  
pp. 1812-1815
Author(s):  
Feng Liang Yin ◽  
Sheng Zhu ◽  
Sheng Sun Hu
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Three Dimensional ◽  
Plasma Arc ◽  
The Status ◽  
Voltage Signal ◽  
Plasma Reflection

A three-dimensional mathematical model has been established to research the relation between the plasma reflection and status of keyhole during the keyhole PAW processing. It has been found that the strength of the plasma reflection is related to the keyhole dimension. Another condition to make the plasma refection appearance is that the keyhole or concave in the pool must be unsymmetrical about the axis of the plasma arc. The mechanism of detecting circuit designed based on the fact that the plasma refection is able to indicate the status of keyhole is mathematically studied. The result shows that the voltage signal in the detecting circuit can be used to indicate the status of keyhole.

A Comprehensive Model for Cutting Dynamics

2005 ◽  
Author(s):  
Achala V. Dassanayake ◽  
C. Steve Suh
Keyword(s):  
Time Domain ◽  
Three Dimensional ◽  
Cutting Speed ◽  
Nonlinear Behavior ◽  
Work Piece ◽  
Special Focus ◽  
Comprehensive Model ◽  
Time Frequency ◽  
Domain Models ◽  
Tool Deflections

A three dimensional dynamic model describing turning operation involving whirling caused by mass imbalance is presented. Both the workpiece and tool deflections affected by nonlinear regenerative forces with instantaneous cutting speed and feed are included. The work piece is modeled as a system of three rotors; namely, unmachined, being machined and machined, connected by a flexible shaft. Special focus is given to the middle rotor where cutting forces act and the new surface is being generated. The nonlinear behavior of the system is studied using instantaneous frequency. The stable and unstable situations are illustrated in time domain as well as time-frequency domain. Models with and without whirling are considered and two sets of results are compared with the experimental results published in the literature.

Modeling of Three-Dimensional Gas Metal Arc Welding With Groove

2007 ◽  
Author(s):  
J. Hu ◽  
H. L. Tsai
Keyword(s):  
Weld Pool ◽  
Arc Welding ◽  
Filler Metal ◽  
Gas Metal Arc Welding ◽  
Three Dimensional ◽  
Plasma Arc ◽  
Droplet Impingement ◽  
Sulfur Species ◽  
Metal Arc Welding ◽  
Arc Pressure

This article analyzes the dynamic process of groove filling and the resulting weld pool fluid flow in gas metal arc welding of thick metals with V-groove. Filler droplets carrying mass, momentum, thermal energy, and sulfur species are periodically impinged onto the workpiece. The complex transport phenomena in the weld pool, caused by the combined effect of droplet impingement, gravity, electromagnetic force, surface tension, and plasma arc pressure, were investigated to determine the transient weld pool shape and distributions of velocity, temperature, and sulfur species in the weld pool. It was found that the groove provides a channel which can smooth the flow in the weld pool, leading to poor mixing between the filler metal and the base metal, as compared to the case without a groove.

Sign in / Sign up

Export Citation Format

Share Document