3D FEA Research Articles

Design and analysis of double stator HE-FSM for aircraft applications

The main objective of aerospace industry is to produce all electric aircraft (AEA) equipped by electrical devices in coming developments. Electrical machines that provide higher torque densities are gaining more interest for researchers to obtain sustainable direct-drive electrical propulsion system for aircraft applications. In addition to lesser weight and higher torque density, a machine should be “fault tolerant” to applied in aerospace applications. A novel machine for high starting torque, identified as flux switching machine (FSM) was established over the last decade. FSMs comprise all effective sources on stator including robust rotor structure. These machines exhibited higher “torque-to-weight ratios” and reliability. Nonetheless, the challenge of developing a machine suitable for aircraft applications goes far beyond electromagnetic design and much deeper into the field of mechanical systems than traditional ones. Thus, a new double stator (DS) hybrid excitation (HE) FSM design employing segmented rotor is proposed and analyzed in this research work. The suggested design for DS HE-FSM comprises of six field excitation coils (FECs) and six permanent magnets (PMs) as their excitation sources. In this research, investigation of DS HE-FSM is accomplished with respect to flux linkage, back EMF, cogging torque and torque analysis based on 2D FEA.

Does overlay preparation design affect polymerization shrinkage stress distribution? A 3D FEA study

This study evaluated the polymerization shrinkage stress of three tooth preparation designs for indirect ceramic overlay by finite element analysis: isthmus preparation (IST); without isthmus preparation (wIST); and non-retentive preparation (nRET). The models were created based in prepared dental typodonts and were digitally impressed with an intraoral scanner. The interfaces in all models were considered perfectly bonded and all materials were considered homogeneous, linear, and isotropic. The polymerization shrinkage of the cement layer (100 µm) was simulated and evaluated by maximum principal stress criteria. The stress peaks followed this sequence: restoration = IST (13.4 MPa) > wIST (9.3 MPa) > nRET (9 MPa); cement layer = IST (16.9 MPa) > wIST (12.6 MPa) > nRET (10-7.5 MPa); and teeth = IST (10.7 MPa) > wIST (10.5 MPa) > (9 MPa). For the cement layer, the non-retentive preparation (nRET) had the lowest shrinkage stress from all the groups, obtaining a more homogeneous stress distribution on the cement surface. Regarding the abutment teeth, the IST generated a higher shrinkage stress area on the dental structure, concentrating higher stress magnitude at the axiopulpar and axiogingival angles. Non-retentive preparation seems to reduce polymerization shrinkage stress.

Technique for shortening the term of periodic inspection of a steam turbine utilizing 3D shape measurement and FEA

Technique for shortening the term of periodic inspection of a steam turbine utilizing 3D shape measurement and FEA

3D 단부효과가 영구자석 동기전동기의 스큐 착자각도에 따른 코깅토크 특성에 미치는 영향에 관한 연구

The cogging torque of a permanent magnet synchronous motor (PMSM) using an ring type permanent magnet (PM) can effectively reduce the cogging torque by skew magnetization of the PM. In previous studies on skew magnetization to reduce cogging torque use the assumption that the same cogging torque occurs at all points in the stack length direction. However, in this paper, it was found that the value of the cogging torque generated in the motor is different for each position in the stack length direction due to the 3D end effect. From this, it was revealed that the existing 2D FEA could not accurately calculate the cogging torque according to the skew magnetization angle. In order to accurately calculate the cogging torque according to the skew magnetization, a 3D FEA that can take into account the 3D end effect is essential. In this paper, the effect of the 3D end effect on the cogging torque characteristics according to the skew magnetization angle of the PM motor was analyzed through a comparison of 2D FEA and 3D FEA analysis.

Usability of finite elements based on the absolute nodal coordinate formulation for deformation analysis of the Achilles tendon

This work explores the modelling of soft tissues, particularly the Achilles tendon, using the absolute nodal coordinate formulation (ANCF).The anisotropic Gasser–Ogden–Holzapfel (GOH) potential energy function provided the necessary anisotropic elastic feature descriptions. A generalized one-dimensional Maxwell model described the viscoelastic effects. Finally, a parameter-based damage model characterized the effects of repetitive loading. We used an objectivity test to establish multibody system dynamics usability. The test ascertains whether or not the developed elements can adequately describe rigid body motion and therefore be applied to describe large deformation in whole bodies. Comparing our results against high-fidelity ANSYS 3D FEA solutions served as verification. To further ensure the validity of the obtained solutions, our results were also compared against test results. For modelling material behaviour, the developed ANCF elements demonstrated substantial fidelity, and simulation results agreed well with test results and results found in the literature.

2D FEA study of Hertzian contact stress between two cylindrical bodies

Abstract Power transmission machine elements such as gears, cams, and bearings, are subjected to Hertzian contact stress. Ansys is a widely used FEA tool to analyze the Hertzian contact stress problems. In this work, 2D FEA analysis was carried out to understand two cylindrical contacts stress behaviour under plane strain, plane stress, and plane stress with 100 mm thickness using ANSYS 16.2. An initial convergence study was carried out to obtain the optimum mesh and compared with the theoretical value. The simulation was performed using the optimum mesh size between two identical cylinders with appropriate boundary conditions and a load of 5000 N. Von-mises stress, and normalized stress was plotted under plane strain, plane stress, and plane stress with 100 mm thickness. Subsurface stress was observed under plane strain condition, whereas surface stress was achieved from the plane stress and plane stress with 100 mm thickness. The behaviour of a normalized stress plot for plane stress condition is almost similar when compared to the plane strain condition. A gradual decrement in normalized stresses was observed with an average slope range of 2.37–12.38 for both plane strain as well as plane stress conditions. In contrast, rapid decrement in normalized stresses was observed with an average slope range of 15.96–32.85 under plane stress with 100 mm thickness.

Modelling of Quadratic-Surface Sludge Digesters by Smoothed Particle Hydrodynamics (SPH) – Finite Element (FE) Methods

Abstract The quadric-surfaced sludge digester (QSD), also known as the egg-shaped sludge digester, has proven its advantages over traditional cylindrical digesters recently. A reduction in operational cost is the dominant factor. Its shell can be described as a revolution of a parabola with the apex and base being either tapered or spherical. This shape provides a surface free of discontinuities, which is advantageous regarding the efficiency during mixing. Since the shape does not produce areas of inactive fluid motion within the tank, sludge settlement and an eventual grit build-up are avoided. The stresses developed in the shell of the sludge digester, vary along the meridian and equatorial diameters. A non-dimensional parameter, ξ, defines the height-to-diameter aspect ratio which is used to delineate the parametric boundary conditions of the shell’s surface. Three groups of analyses were conducted to determine the orthogonal stresses in the shell of the QSD. The first-principles numerical models ran reasonably quickly, and many simulations were made during the study. The results showed that they were in within the range 5.34% to 7.2% to 2D FEA results. The 3D FEA simulation results were within the range of 8.3% to 9.2% to those from the MATLAB time-history models. This is a good indicator that the first principles numerical models are an excellent time-saving method to predict the behaviour of the QSD under seismic excitation. Upon examining the criteria for the design, analysing the results for the 2D FEA simulations showed that the fill height is not a significant variable with sloshing however the 3D FEA showed that the hydrostatic pressure is a significant variable. With the maximum tensile stress of the 3D-printed Acrylonitrile Butadiene Styrene (ABS)-a common thermoplastic polymer typically used for injection molding applications, being 24.4 MPa, the overall maximum stress of 5.45 MPa, the material can be a viable option for the use of QSD construction in small island developing states (SIDS).

A numerical investigation of the sealing performance and the strength of a raised face metallic bolted flange joint

The development of leakage and strength of a metallic bolted flange joint are investigated in this work. Finite element analyses in 2D and 3D have been developed using ANSYS to study a steel flange and bolt with an aluminium gasket. The pressure-penetration criterion (PPNC) in ANSYS has been used to model fluid leakage propagation between the flange and the gasket. Validation was performed with a benchmark test, using published study of a bolted metallic flange joint; the agreement between the results is excellent. Results showed that the finite element method using PPNC is a good method to study leakage behaviour compared to other methods, which are relatively time-consuming and expensive. The influence of the flange dimensions on the maximum stresses and leakage propagation has been investigated in this study. Furthermore, the agreement between the 3D and axisymmetric 2D FEA models is very good, so the latter can be used to save computational time. This study was undertaken as a preliminary to a larger project about bolted flange joints made of composite materials.

Experimental and numerical prediction and comprehensive compensation of springback in cold roll forming of UHSS

Ultra-high-strength steels (UHSS), for instance, dual phase (DP) and martensitic steels, get growing challenges in strip metal forming processes of car industry manufacturing to achieve lightweight and improve passenger security. Predict and compensate for springback is still a major problems to be solved in cold roll forming (CRF) for complex section materials. In this study, the springback performance UHSS in cold roll forming is discussed by simulation and experimental methods. At the same time, one 3D FEA model was established to analyze the CRF process by COPPA RF and MSC MARC, in which planar swift’s model, anisotropic Hill’s 48 model, and Yid2000-2d model in the company with Yoshida-Uemori kinematic hardening pattern were investigated. Automobile threshold section CRF experiment and springback evaluation carried out through the comparison of numerical results. Considering Yoshida-Uemori kinematic hardening, the anisotropic Yid2000-2d model improves the springback prediction accuracy in CRF car threshold section in comparison with other models. The improved model is used to compensate the springback of product. A new method is proposed, which takes into account angle overbending compensation (AOC), small radius compensation (SRC), and revere-bending compensation (RBC) based on roll shape design. The method, which we call “USTB-Durable Integration of Springback Control (UDI),” is general for it considers the fact radius and angle would occur during springback. Compared with the AOC, SRC, and RBC method, the new method has higher precision especially for the springback compensation of ultra-high-strength complex section in CRF. The researchers are expected to conduct design engineer to calculate and compensate the springback trend before applying roller design to actual production.

Yokeless Axial Flux Surface-Mounted Permanent Magnets Machine Rotor Parameters Influence on Torque and Back-Emf

The paper presents the results of a 3D FEA simulations series of a dual air gap Axial Flux (AF) electric machine with Surface-Mounted Permanent magnets (SPM) with parameterized rotor geometry. Pole number and pole span influence on back-emf, as well as cogging and ideal electromagnetic torques angular characteristics were investigated for each model with the common segmented yokeless stator with concentric windings. Synchronous and BLDC drives supply were used to estimate back-emf distortion. Ideal torque ripple and cogging torque spectra were analyzed. It was concluded that the number of poles closer to the number of slots with ~0.8 pole span tends to yield good torque density with the lowest cogging torque, back-emf distortion and ideal torque ripple.

A comparative study between zirconia and titanium abutments on the stress distribution in parafunctional loading: A 3D finite element analysis.

Zirconia has become a popular biomaterial in dental implant systems because of its biocompatible and aesthetic properties. However, this material is more fragile than titanium so its use is limited. The aim of this study was to compare the stresses on morse taper implant systems under parafunctional loading in different abutment materials using three-dimensional finite element analysis (3D FEA). Four different variations were modelled. The models were created according to abutment materials (zirconia or titanium) and loading (1000 MPa vertical or oblique on abutments). The placement of the implants (diameter, 5.0 × 15 mm) were mandibular right first molar. In zirconia abutment models, von Mises stress (VMS) values of implants and abutments were decreased. Maximum and minimum principal stresses and VMS values increased in oblique loading. VMS values were highest in the connection level of the conical abutments in all models. Using conical zirconia abutments decreases von Mises stress values in abutments and implants. However, these values may exceed the pathological limits in bruxism patients. Therefore, microfractures may be related to the level of the abutment.

Examination of compression effects on PEMFC performance by numerical and experimental analyses

In the present study, the effects of compression method on Proton Exchange Membrane Fuel Cell (PEMFC) performance were investigated both numerically and experimentally. Total deformation of the components within the PEMFC was simulated by ANSYS three-dimensional finite element analysis (3D FEA). Moreover, geometrical and material properties of all components of PEMFC such as bipolar plates (BPP), membrane electrode assembly (MEA), gasket, current collector plate (CCP), screw and nut were implemented for accurate simulation of compression. In the experimental part, PEMFC tests were performed with 25 cm2 active area single cell having 3 channel parallel in series (3 PS) flow channel via PEMFC test station with H2 and air at 60 °C. The maximum power density was achieved as 0.458 W/cm2 and 0.480 W/cm2 for bolt compression and clamping plates compression, respectively. The equivalent stress values were found as 120 MPa that under 4389 N the clamping plates and 1600 MPa under bolt compression with 1.3 Nm torque. When numerical and experimental studies are examined together, it is seen that bolt compression has higher deformation and less equivalent stress than clamping plates compression.

Study on the Cutting Temperature of the Textured Tool by 3D FEA Simulation

Temperature plays an important role in the life of cutting tools. However, it is sometimes difficult to observe instantaneously because of limited data acquisition, especially for the textured tool. In this paper, the performance of microgroove textured cutting tools for three-dimensional (3D) oblique dry turning of AISI 1045 steel was studied by finite element simulation. The effects of width, depth and spacing of strip micro-texture on cutting temperature and the effect of cutting speed on cutting temperature of strip micro-texture tool were studied. The results show that the maximum temperature of the tool and the tip temperature first increase and then decrease with the increase of micro-texture width. When the micro-texture depth increases, the maximum temperature and the tool tip temperature decrease first and then increase. The highest temperature and tip temperature of the tool gradually increase with the increase of micro-texture spacing. The highest temperature and tip temperature of the tool increase with the increase of cutting speed, feed speed and cutting depth. In addition, the effective mechanism of micro-texture parameter for the temperature was proposed. It provides profound guidance for optimizing the microstructure parameters and cutting process of cutting tools according to cutting temperature in this study. It also provides an effective and practical method for the design, innovation and development of micro-textured tools.

Finite elements analysis of the temporomandibular joint disc in patients with intra-articular disorders

BackgroundIntra-articular disorders (ID) or anterior and/or medial displacement of the temporomandibular joint disorder (TMJ) disc are the most common form of TMJ dysfunction (TMD). TMD causes changes in the friction coefficient during TMJ movement. Herein, we provided a three-dimensional (3D) finite-elements model (FEM) including the maxilla, disc, and mandible and evaluated the stress distribution with different friction coefficient.MethodsFourteen volunteers without TMD and 20 patients with MRI-diagnosed TMD were selected. CT and MRI data were collected to build the 3D FEA model of the mandible and TMJ disc. Stress distribution with different friction coefficient was measured.ResultIn the normal model, stress distribution on the TMJ disc was 2.07 ± 0.17, 1.49 ± 0.14, and 1.41 ± 0.14 MPa with 0.001, 0.3, and 0.4 friction coefficient, respectively. In the TMD model, stress distribution was 3.87 ± 0.15, 7.23 ± 0.22, and 7.77 ± 0.19 MPa respectively.ConclusionWhen the friction coefficient of the side with anterior displacement increased, stress on the disc, condyle and mandible of the opposite side increased. Simultaneously, stress values of the disc, condyle and mandible were higher than those of the normal lateral joint.

Evaluation of Heat Transfer Performance of Hypervapotron Elements in Two Phase Flow Devised in Indian test facility

Abstract Indian Test Facility (INTF) is a testbed to carry out neutral beam experiments where beam with peak power densities reach about 66 MW/m2 and incident on calorimeters. To survive such thermal fluxes, Hypervapotron (HV) elements are devised in designing calorimeters. The HV element has a finned surface inside and working in a subcooled nucleate boiling regime with water as a coolant. HV elements are efficient heat transfer technologies made from high thermal conductive materials (CuCrZr – Copper alloy) and capable of removing heat flux densities about 10−30 MW/m2 w.r.t various coolant flow conditions. In this paper, efforts are undergone to evaluate heat transfer performance of these elements in three approaches – a) 3D FEA using Empirical correlations available in literature, b) 2D CFD in ANSYS CFX, c) Conducting high heat flux experiments on the HV element and compared the methodologies and estimate the safe operating boundaries for INTF operation.

Relationships of Stresses on Alveolar Bone and Abutment of Dental Implant from Various Bite Forces by Three-Dimensional Finite Element Analysis.

Occlusal trauma caused by improper bite forces owing to the lack of periodontal membrane may lead to bone resorption, which is still a problem for the success of dental implant. In our study, to avoid occlusal trauma, we put forward a hypothesis that a microelectromechanical system (MEMS) pressure sensor is settled on an implant abutment to track stress on the abutment and predict the stress on alveolar bone for controlling bite forces in real time. Loading forces of different magnitudes (0 N–100 N) and angles (0–90°) were applied to the crown of the dental implant of the left central incisor in a maxillary model. The stress distribution on the abutment and alveolar bone were analyzed using a three-dimensional finite element analysis (3D FEA). Then, the quantitative relation between them was derived using Origin 2017 software. The results show that the relation between the loading forces and the stresses on the alveolar bone and abutment could be described as 3D surface equations associated with the sine function. The appropriate range of stress on the implant abutment is 1.5 MPa–8.66 MPa, and the acceptable loading force range on the dental implant of the left maxillary central incisor is approximately 6 N–86 N. These results could be used as a reference for the layout of MEMS pressure sensors to maintain alveolar bone dynamic remodeling balance.

Compensation analysis of longitudinal end effect in three‐phase switched reluctance linear machines

The longitudinal end effect of switched reluctance linear machine (SRLM) makes the electromagnetic characteristics of different phases unbalanced, especially in magnetic flux distributions. These discrepancies unbalance phase currents and aggravate the force ripple of SRLM, which are verified on a double-sided SRLM. This study aims to analyse the influence of the longitudinal end effect on SRLMs and to investigate simple but practical compensation methods for the performance improvement of linear machines. Through magnetic circuit analysis, a new compensation method which is widening stator end poles is proposed for the first time. Three-dimensional finite element analysis (3D FEA) shows that this new method can decrease the force factor by about 93.9%, while the previously used method which is adding auxiliary stator poles can decrease the force ripple factor by only about 27.5%. In addition, the proposed method needs less extra space than the previous method. Hence, the new compensation method is more practical and more efficient. Furthermore, the theoretical value of optimal width of stator end poles is expressed, and its effectiveness is confirmed by sensitivity analysis.

Influence of skewing design for reduction of force ripples in DSL-SynRM using 3D FEA

Influence of skewing design for reduction of force ripples in DSL-SynRM using 3D FEA

Electromagnetic Performances and Main Parameter Sensitivity Effect on Unbalance Magnetic Flux in a New Single-Phase FEFSM with Segmental Rotor

Three-phase field excitation flux switching motor (FEFSM) with salient rotor structure has been introduced with their advantages of rotor easy temperature elimination and controllable FEC magnetic flux. Yet, the salient rotor structure is found to lead a longer magnetic flux path between stator and rotor parts, producing a weak flux linkage along with low torque performances. Hence, a new structure of single-phase FEFSM using segmental rotor with non-overlap windings is proposed with advantages of shorter magnetic flux path, light weight and robust rotor structure. Analysis on fundamental magnetic flux characteristics, armature and FEC magnetic flux linkages, cogging torque, back-Emf, various torque capabilities, refinement of unbalance magnetic flux, and torque-power versus speed characteristics are conducted using 2D FEA through JMAG Designer version 15. The results show that magnetic flux amplitude ratio has been improved by 41.2% while the highest torque and power achieved are 1.45 Nm and 343.8 W, respectively.

Modeling the influence of roughness on nanoindentation data using finite element analysis

Nanoindentation is a popular tool for the study of hardness and elasticity of materials at the nanoscale. However, the roughness of such samples may violate the basic assumptions under which these parameters can be evaluated. In this article we study the effects of roughness on the reduced modulus of contact. A systematic study using 3D FEA modeling to map the apparent modulus on a real rough surface as measured by AFM is presented. The requirements for the assessment of 2D modulus maps are compared to the requirements for the assessment of the average value and found to be much higher, approx. by a factor of ten. The possibility to use a simplified Hertzian model based on the local curvature is explored and found to give acceptable results, at least from a qualitative point of view.