fem method
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Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 621
Author(s):  
Fugang Zhai ◽  
Liu Yang ◽  
Wenqi Fu ◽  
Haisheng Tong ◽  
Tianyu Zhao

This paper investigates the electromagnetic torque by considering back electromagnetic force (back-EMF) trapezoidal degrees of ironless brushless DC (BLDC) motors through the two-dimensional finite element method (2-D FEM). First, the change percentages of the electromagnetic torque with back-EMF trapezoidal degrees, relative to those of PMs without segments, are investigated on the premise of the same back-EMF amplitude. It is found that both PM symmetrically and asymmetrically segmented types influence back-EMF trapezoidal degrees. Second, the corresponding electromagnetic torque, relative to that of PMs without segments, is studied in detail. The results show that the electromagnetic torque can be improved or deteriorated depending on whether the back-EMF trapezoidal degree is lower or higher than that of PMs without segments. Additionally, the electromagnetic torque can easily be improved by increasing the number of PMs’ symmetrical segments. In addition, the electromagnetic torque in PMs with asymmetrical segments is always higher than that of PMs without segments. Finally, two ironless PM BLDC motors with PMs symmetrically segmented into three segments and without segments are manufactured and tested. The experimental results show good agreement with those of the 2-D FEM method. This approach provides significant guidelines to electromagnetic torque improvement without much increase in manufacturing costs and process complexity.


2022 ◽  
Vol 961 (1) ◽  
pp. 012014
Author(s):  
Z A Alkaissi

Abstract A research aim was to achieve a finite element model for predictive pavement cracking implementing ABAQUS software ver.6.12.1. A simulation model for pavement structure was implemented to analyze the propagation of cracks within flexible pavement. The X-FEM method adopted in this research based on the functions of interpolation that can characterize the displacements near the crack zone, initial crack was defined at the bottom of asphalt layer. The estimated results illustrated that X-FEM was efficient for the simulation of cracks in pavement structures without the need for re meshing during crack propagation evolution process. Finally, inclusive simulation results probed the considerable effect for improvement of bonding layers to enhance the service life of pavement in terms of decreasing the rate of crack propagation. The crack was propagated upwards from depth end of asphalt layer to pavement surface and deviated from center of applied pressure with an inclination of almost 300 in the third upper zone of asphalt layer while the pre-crack point was always located in the bottom of asphalt layer in pavement model because of the different characteristics of their bonding bases. In the crack zone the permanent deformation was increased gradually from the crack edge along vertical direction of crack spread due to tensile stresses concentration at the crack zone. The action of horizontal and vertical stresses affect crack propagation and growth vertically to the direction of higher horizontal tensile stresses, and along direction of higher compression vertical stresses.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Liang Zhang ◽  
Qidi Wang ◽  
Xin Li

The prediction of vibration characteristics was studied in the mistuned bladed disk by the mobile interface prestressed component mode synthesis (CMS) superelement method. When the strongly, generally, and weakly coupling in the mistuned bladed disk, according to the results of the direct FEM method, the prediction accuracy of this method was verified and compared with the fixed-interface CMS method by using the relative error of dynamic frequency, vibration mode matching function, and dimensionless root mean square error of vibration amplitudes. It is pointed that for mistuned bladed disk in the strong coupling, the prediction accuracy of dynamic frequency and vibration amplitudes are higher by the mobile interface CMS method and the vibration modes are matched with the direct method. In weak coupling, the results of dynamic frequency and vibration modes predicted by the mobile interface CMS method and the fixed-interface CMS method are consistent with the direct method, but the vibration amplitudes’ prediction error of the mobile interface CMS method is lower than that of the fixed-interface CMS method. In general coupling, the mobile interface CMS method has higher dynamic frequency prediction accuracy at low order, and the two methods have comparable dynamic frequency prediction accuracy at high order. The vibration modes predicted by the two methods are matched with the direct FEM method, and the prediction accuracy of vibration amplitude by the mobile interface CMS method is better than that of the fixed-interface CMS method. The results indicate that the mobile interface CMS method could more accurately predict vibration characteristics of the mistuned bladed disk with different coupling degrees and could be an effective measurement for studying the vibration characteristics of the mistuned bladed disk system.


2021 ◽  
Author(s):  
Yildirim İsmail Tosun

The soft rock and wet slopes increase landslides over 50 m long creep slide and risk assessment for long steep slide in Şırnak open-pit coal mining should be searched in asphaltite quarries. The Avgamasya quarries No1 and 2 at critical depths and road bench sites in Şırnak, reaching over 120 m height with 60–65° shale slopes, developing major creep factors and other factors for landslide in the deep quarry locations is resulting debris rock falling or free sliding. The pore pressure measurements by measurements of water levels in four wells and water flow counting as the mining safety in recent years. This research provided rock slope stability patterns and crack propagation control of the hazardous location and formation cracks. The stages of creep experimentation explored the geophysical characteristics and thaw and freeze testing of rock samples. For this aim, two different long sliding areas with similar geoseismical conditions, two main analyzing methods, and patterns of researches were developed. Firstly, data on crack propagation in situ rock shale faces over certain time periods were determined. Displacement measurements over highly saturated shale—limestone contacts over the base of crack counting in a meter scale such as Rock Quality Designation (RQD) scoring of drilling logs. Secondly, hydrological water level logs were taken into consideration. On the other hand, due to that creep effect over freeze crack propagation unseen cause instability over wet sliding surfaces over 50 m, long sliding surface matter over slopes, poly linear or circle type creep sliding or rock tumbling falling failure types, and GEO5 slope stability, slice analysis will be advantageous instead of Finite Element Method (FEM) method.


2021 ◽  
Vol 1199 (1) ◽  
pp. 012010
Author(s):  
Łukasz Gierz ◽  
Tomasz Zwiachel ◽  
Mikołaj Spadło ◽  
Zharkevich Olga ◽  
Aliya Kukesheva ◽  
...  

Abstract Most of the front loaders are compact structures that do not allow loading at greater heights. On the Polish and foreign market, there was a need to develop a front loader design that would allow to increase the loading height. As a result, the front loader was designed a front loader with the possibility of extending the arms for the Kubota M5 agricultural tractor. The system enables unloading and loading of cubes, straw and hay bales on higher piles. Before starting the design process, the available front loader solutions were analyzed and on this basis, three concepts of design solutions were proposed. These concepts were scored on the basis of the adopted criteria and the one with the highest number of points was selected. For the selected concept, strength analytical calculations and verification calculations using the FEM method were performed. The developed loader is innovative compared to other available designs and has a good chance of implementation.


AIP Advances ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 115304
Author(s):  
Wei Chen ◽  
Chang-kyu Rheem ◽  
Shuangxi Xu ◽  
Xiaobin Li

Author(s):  
Benessalah Djamel ◽  
Houassine Hamza ◽  
Nadir Kabache ◽  
Moussaoui Djeloul

<span lang="EN-US">The interest in synchronous reluctance machine (SynRM) does not stop increasing in recent decades; this is encouraged by their numerous advantages. This paper presents a nonlinear parametric study of the SynRM using finite element method (FEM) method. After a brief introduction and a description of the basic principles of SynRM an investigation and an evaluation of the effects of some influential parameters’ variables of the machine on the torque and magnetic losses is highlighted. The SynRM is created using ANSYS Maxwell software, using 2D FEM. The analyses are performed in the ANSYS Maxwell. The influence of the thickness of the air gap, the opening angle of the rotor, the width and the height of the stator tooth are listed and discussed. The obtained results reveals that the opening angle of the rotor and the air gap produces a large effect over the torque of the SynRM. In order to validate, the finite element model of the studied machine, experimental tests were carried out on designed machine such as the measurement of the synchronous inductance, the torque and the different losses. The experimental results are in agreement with those obtained by FEM.</span>


2021 ◽  
Vol 1207 (1) ◽  
pp. 012020
Author(s):  
L J Kong ◽  
Y W Huang ◽  
Q B Yu ◽  
J Y Long ◽  
S Yang

Abstract Complicated industrial robot structure and harsh working conditions may cause signal features collected in the condition monitoring process to be seriously disturbed. In this paper, a joint feature enhancement mapping and reservoir computing (FEM-RC) method is presented to handle the industrial robot fault diagnosis problem. Firstly, a feature enhancement mapping (FEM) method is proposed to achieve intraclass distance minimization and interclass distance equalization to obtain an enhanced feature matrix. Then, the first reservoir computing (RC) network is adopted to map the original feature matrix to the feature enhancement matrix, and the second RC network is for fault type classification. The results of the experiment carried out on a six-axial industrial robot demonstrate that compared with other peer models, the present FEM-RC has better fault diagnosis performance and robustness.


2021 ◽  
Author(s):  
LI Xing lin ◽  
Hongjun Hu ◽  
Zhang Huiling ◽  
Zhao Hui ◽  
ZHANG Dingfei ◽  
...  

Abstract A new severe plastic deformation for manufacturing thin-walled tube made of AZ31 magnesium alloy called TEB(Tube-Extrusion-Bending ) process, which combines direct extrusion with two step bending,has been developed to manufacture tube.The TEB process has been researched by using finite element modeling (FEM) method. The rules of extrusion temperatures and the extrusion forces varying with process parameters have been developed. A TEB process with installed containers and dies has been constructed to perform tests in order to validate the FEM model with different process conditions. And the microstructures evolution have been researched based on effective strains evolution. The results showed that refined and uniform microstructures can be achieved by TEB process. The research results showed that the TEB process would produce the serve plastic deformation and improve the recrystallization of the grains.The comparisons of FEM simulation and experimental results have been made to obtain the relative important principles of TEB process.


2021 ◽  
Vol 2045 (1) ◽  
pp. 012007
Author(s):  
Y D Fu ◽  
S Yang ◽  
G Li ◽  
X L Lin ◽  
H D Zhang ◽  
...  

Abstract In the design of large-scale steel structure, the design calculation of the structure is usually based on the service state. But in the process of steel structure construction, the displacement and stress produced in the construction process cannot be completely consistent with that in the design state. With the progress of construction process, the deformation and stress caused by self-weight and construction load gradually accumulate until the structure is formed, which will produce construction error relative to the design state. In this paper, FEM method was used to simulate the construction process of the steel grid roof of the theater in the Beijing Sub Center Theater project, and the influence of the accumulated deformation and stress on the mechanical properties of the structure during the construction process was analyzed. The results show that the cumulative deformation and stress in the construction process have a great influence on the final deformation and stress distribution of the structure. The maximum vertical displacement in the actual construction state is 599.6% of that in the design state, and the maximum stress is 119.7% of that in the design state. This will lead to the difference between the construction-completed structure and the design structure, which makes the design result dangerous. The measures to optimize the construction process were also given in this paper, which provides guidance for the construction process of large-scale steel structure.


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