scholarly journals Analysis of an Approach for Detecting Arc Positions During Vacuum Arc Remelting Based on Magnetic Flux Density Measurements

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Miguel F. Soler ◽  
Kyle E. Niemeyer

Vacuum arc remelting (VAR) is a melting process for the production of homogeneous ingots, achieved by applying a direct current to create electrical arcs between the input electrode and the resultant ingot. Arc behavior drives quality of the end product, but no methodology is currently used in VAR furnaces at large scale to track arcs in real time. An arc position sensing (APS) technology was recently developed as a methodology to predict arc locations using magnetic field values measured by sensors. This system couples finite element analysis of VAR furnace magnetostatics with direct magnetic field measurements to predict arc locations. However, the published APS approach did not consider the effect of various practical issues that could affect the magnetic field distribution and thus arc location predictions. In this paper, we studied how altering assumptions made in the finite element model affect arc location predictions. These include the vertical position of the sensor relative to the electrode–ingot gap, a varying electrode–ingot gap size, ingot shrinkage, and the use of multiple sensors rather than a single sensor. Among the parameters studied, only vertical distance between arc and sensor locations causes large sources of error and should be considered further when applying an APS system. However, averaging the predicted locations from four evenly spaced sensors helps reduce this error to no more than 16% for a sensor position varying from 0.508 m below and above the electrode–ingot gap height.

2016 ◽  
Author(s):  
Miguel Soler ◽  
Kyle Evan Niemeyer

Vacuum arc remelting (VAR) is a melting process for the production of homogeneous ingots, achieved by applying a direct current to create electrical arcs between the input electrode and the resultant ingot. Arc behavior drives quality of the end product, but no methodology is currently used in VAR furnaces at large scale to track arcs in real time. An arc position sensing (APS) technology was recently developed as a methodology to predict arc locations using magnetic field values measured by sensors. This system couples finite element analysis of VAR furnace magnetostatics with direct magnetic field measurements to predict arc locations. However, the published APS approach did not consider the effect of various practical issues that could affect the magnetic field distribution and thus arc location predictions. In this paper, we studied how altering assumptions made in the finite element model affect arc location predictions. These include the vertical position of the sensor relative to the electrode-ingot gap, a varying electrode-ingot gap size, ingot shrinkage, and the use of multiple sensors rather than a single sensor. Among the parameters studied, only vertical distance between arc and sensor locations causes large sources of error, and should be considered further when applying an APS system. However, averaging the predicted locations from four evenly spaced sensors helps reduce this error to no more than 16 % for a sensor position varying from 0.508 m below and above the electrode-ingot gap height.


Author(s):  
Hongyan Ding ◽  
Zuntao Feng ◽  
Puyang Zhang ◽  
Conghuan Le

Abstract The onshore pre-fabrication technology for composite bucket foundations takes “prefabrication-assembly-lifting” as the core concept. The practice of pre-fabrication of upper and lower structures is prefabricated respectively. In the research of hoisting engineering technology, combined with the structural form and construction requirements of composite bucket foundation, the assembly scheme of the upper prestressed concrete transition section and the lower steel bucket and the hoisting scheme of integral foundation with compartments were designed. The finite element model in the lifting process of composite bucket foundation was established by the large-scale general finite element analysis software ABAQUS. For the optimization analysis of the lifting point arrangement during hoisting process, the number, position and arrangement form of lifting points are simulated and analyzed. The results show that the maximum value of the principal stress of the concrete transition section structure appears in the assembly stage with the lower steel bucket, and the structure checking calculation should be carried out as the most unfavorable lifting condition in construction; the peak point of structural stress is at the junction of girder and secondary beams and inner ring beams of concrete roof, which belongs to the weak position of force transmission. In construction, it should be paid attention to as the key part of monitoring to ensure composite bucket foundation is under reasonable stress and the stability in the lifting process. The research results can provide guidance and reference for the future batch production and standardization production construction for composite bucket foundations.


2012 ◽  
Vol 591-593 ◽  
pp. 728-732
Author(s):  
Rong Zhang

This paper uses non-linear finite element method to structurally analyze top flanged joint system of a MW wind turbine, sets up a finite element model of top flanged joint system by applying finite element analysis software MSC.Marc/Mentat, makes an analysis on the stress distribution of key components of top flanged joint system under ultimate operating mode based on applying appropriate boundary condition and loads, and carries out security examination on top flange and joint bolt. Result shows that key components of the top flanged joint system can satisfy design requirements, and it has a guiding role for rational design and performance improvement of large scale wind turbine flange, which can be used in structural analysis of other flanged joint systems, and has certain practical value in the aspect of engineering.


2013 ◽  
Vol 712-715 ◽  
pp. 1080-1083
Author(s):  
Hu Qi Wang ◽  
Hai Zhao He ◽  
Hai Yan Lu ◽  
Rong Xing Huang

A large-scale forklift's wheel rim appeared cracking phenomenon in the course of use. This article summarized and analyzed force of the forklift's wheel rim according to the typical working conditions of forklift, and calculated the load of various working conditions. It provided the correct boundary conditions for the finite element analysis of the wheel rim [. After the analysis of wheel rim's three typical conditions, found the weak parts of the structure of the rim, and this part was consistent with the feedback part, so it proved correct of the finite element analysis model. Clever was used ribbed-plate and punching groove to strengthen the weak part of wheel rim and the finite element model was used to calculate and check the improved wheel rim again. The results showed that the improved wheel rim stress decreased quite, so the measure was correct.


2013 ◽  
Vol 753-755 ◽  
pp. 1196-1200
Author(s):  
Lu Yu Huang ◽  
Yang Gao ◽  
Xia Cao

Based on the construction features of the steel structures of a type of electrical dust precipitator, a finite element model is established with large-scale finite element analysis software ANSYS, and the structure stress and displacement of the model under all sorts of loads are analyzed with the frontal solution method. The results indicate that analysis is relatively accurate, the finite element model and the analysis method is appropriate. The result can be further used for optimization design of the electrical precipitator steel structures.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2437
Author(s):  
Jonathan Sjölund ◽  
Sandra Eriksson

Electromagnetic modelling of electrical machines through finite element analysis is an important design tool for detailed studies of high resolution. Through the usage of finite element analysis, one can study the electromagnetic fields for information that is often difficult to acquire in an experimental test bench. The requirement for accurate result is that the magnetic circuit is modelled in a correct way, which may be more difficult to maintain for rare earth free permanent magnets with an operating range that is more likely to be close to non-linear regions for the relation between magnetic flux density and magnetic field strength. In this paper, the inclination angles of the magnetic flux density, magnetic field strength and magnetization are studied and means to reduce the inclination angles are investigated. Both rotating and linear machines are investigated in this paper, with different current densities induced in the stator windings. By proper design of the pole shoes, one can reduce the inclination angles of the fields in the permanent magnet. By controlling the inclination angles, one can both enhance the performance of the magnetic circuit and increase the accuracy of simpler models for permanent magnet modelling.


2014 ◽  
Vol 553 ◽  
pp. 570-575
Author(s):  
Daniel John Lowe ◽  
Raj Das ◽  
George Charles Clifton ◽  
Namasivayam Navaranjan

The degradation of the connection between shear studs and concrete is a complicated phenomenon that depends on many factors, including; interfacial properties, concrete crushing and steel yielding. The purpose of this paper is to outline the scope and methodology of the research project being undertaken to characterise the shear stud-concrete interface of a composite beam using finite element analysis. A mesoscopic model will be created for a section of the interface. With the use of a multi-scale approach, the mesoscopic model will be incorporated into a global model. The influence of steel roughness and mechanical properties will be included. Concrete is to be modelled as heterogeneous, comprising discrete regions of aggregate, cement matrix, and an interfacial transition zone (ITZ). The effect of the ITZ will be taken into account using a zero thickness cohesive element. Experimental testing using a push-up rig is to be conducted to verify the numerical models. The ultimate aim is to develop a simplified representation of the shear stud-concrete interface that can be used in a large scale finite element model of a composite member to correctly capture the behaviour of the shear stud-concrete interface in the elastic and inelastic state.


2013 ◽  
Vol 838-841 ◽  
pp. 1096-1101 ◽  
Author(s):  
Feng Jiang Qin ◽  
Jin Di ◽  
Jie Dai ◽  
Guang Ling Li

A 3-D finite element model for Yueyang Dongting Lake bridge was established with a large scale general finite element analysis software, and the subspace iteration method was adopted to analyze the natural vibration characteristics of the bridge, meanwhile, the influences of settings different types of central buckles at the mid-span of the main spans between the main cables and girder on the dynamic behaviors of the long-span suspension bridge with deck-truss composite stiffening girder were studied. The results show that compared with only setting short hanger cable at mid-span, the the whole rigidity of suspension bridge is raised and the natural frequencies increase by the setting central buckle, but various types of vibration modes are affected in different extents; among all of these vibration modes, the antisymmetric vibration and Longitudinal floating of stiffening girder are most obviously affected. The stiffness of central buckle has a great influence on the vibration of main cable, while compared with only setting short hanger cable, the vibration of main cable increases 7.32% while setting the rigid central buckle. The conclusions of this paper provide theoretical basis for the using of central buckle in long-span suspension bridge.


2013 ◽  
Vol 762 ◽  
pp. 584-589 ◽  
Author(s):  
Yun Long Chang ◽  
Lin Lu ◽  
Xiao Long Liu ◽  
Bo Young Lee

The finite element analysis on temperature field and stress field during submerged-arc welding (SAW) was carried out by means of assembly language of FORTRAN on the base of ABAQUS. A finite element model was established to study the effects on weld bead formation by using longitudinal magnetic field of low-frequency and different process parameters loaded with moving heat source. A practical SAW experiment was conducted to verify the results of the numerical simulation. It was shown that a molten pool with a wider weld face and a lower penetration could be obtained by the control of longitudinal magnetic field of low-frequency. In addition, the fusion line after this treatment was smoother than with conventional SAW. The results of practical SAW experiment were consistent with those of the numerical simulation. It was confirmed that the longitudinal magnetic field of low-frequency could contribute in diminishing the dilution rate and improving the performance of surfacing layers.


2012 ◽  
Vol 150 ◽  
pp. 165-169 ◽  
Author(s):  
Gang Zhang ◽  
Xue Zhang ◽  
De De Jiang ◽  
Ming Yan Li ◽  
Jian Zhang

According to the property of contact problem, the calculation formula of contact stress of cross-roller slewing bearing is derived under the action of eccentric axial load. The finite element model of slewing bearing is analyzed in ANSYS, and then the finite element analysis software is used to analyze the contact stress. In this way, the distribution condition of contact stress between roller and rings is obtained. By comparing the finite element analysis results with theoretical analysis results, the correctness of finite element analysis is certified, which provides a guide for the design and optimization of slewing bearing.


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