3D FEM Simulation Research Articles

3D FEM Simulation and Analysis of Fractal Electrode-Based FBAR Resonator for Tetrachloroethene (PCE) Gas Detection

This paper presents the FEM modeling and simulation of a thin-film bulk acoustic resonator (FBAR) for a tetrachloroethene (PCE) gas-sensing application. A zinc oxide layer is used as a piezoelectric material; an aluminum layer is used as the electrode material in the structure of the FBAR. Polyisobutylene (PIB) is used as the sensitive layer for PCE gas detection. The study was carried out in commercially available FEM-based COMSOL software. The proposed structure was exposed to six different organic gases with concentrations ranging from 0 to 1000 ppm. The structure showed high selectivity for PCE gas. Incorporating the 3rd-order Hilbert fractal geometry in the top electrode of the FBAR increased the sensitivity of the sensor which showed high selectivity for PCE gas detection. A sensitivity enhancement of 66% was obtained using fractal geometry on the top electrode of the FBAR without alteration in size or cost. In addition, a reduction in the cross-sensitivity was achieved. Further, the PIB layer thickness and active area of the FBAR were optimized to obtain high sensitivity. The equivalent circuit was also analyzed to understand the behavior of the sensing effect and mechanism.

2D FEM simulation and experimental verification of Al 7075‐T6 during turning process

AbstractIn this work, temperature distribution, effective stress and strain distribution in Al 7075‐T6 material and plastic flow of materials during turning process have been studied using Deform 3D v11.0 software. The four different points (P1, P2, P3, and P4) were chosen at the different locations in the cylindrical workpiece and the graph has been plotted with different parameters namely, temperature distribution, effective stress and strain. For temperature distribution, a good agreement has been found between simulation and experimental results at P4. The following results obtained from the simulation: In tertiary zone, the maximum temperature of specimen reaches upto 142 °C at points P1 due to friction between the tool rack face and the lower surface of chip. Maximum effective stress value reaches upto 650 MPa and 704 MPa at P1 and P4 respectively in the first sticking zone due to the combined effect of high normal force by tool edge and ploughing force. The effective strain value at P1 and P4 obtained, strain at P4 reaches maximum compare to P1 due to friction and unven temperature distribution. Additionally, chip analysis has been performed with microscopic image.

An analytical method for calculating the natural frequencies of spatial compliant mechanisms

Compliant mechanisms are becoming increasingly important in both research and industry. The design and the static analysis of such mechanisms has made much progress in recent years, yet comparatively little research has been done on their dynamic behaviour. The aim of this paper is to advance the dynamic analysis of spatial compliant mechanisms by pursuing the calculation of their natural frequencies. So far, their determination is only possible with time-consuming 3D-FEM simulations or via pseudo-rigid-body models and Lagrangian equations. An analytical method is developed to simplify and accelerate the calculation of the natural frequencies of compliant mechanisms. The method is integrated into an algorithm on which a graphical user interface is developed to allow the design and calculation of the system in the most time efficient and intuitive way. The results are verified by 3D-FEM simulations and validated through an experiment. The evaluation shows good agreement with the reference models. The results of this paper allow a reliable and efficient calculation of natural frequencies and serve to facilitate further work regarding the dynamic analysis of compliant mechanisms.

A new shear formula for tapered beamlike solids undergoing large displacements

In many engineering applications it is often necessary to determine the flow of shear stresses in the cross-sections of beamlike bodies. Taking a cue from Jourawski's well-known formula, several scholars have proposed expressions for evaluating the shear stresses in non-prismatic linear elastic beams, where longitudinal variations in the size and shape of the cross-sections produces complex stress fields. In the present paper, a new shear formula, derived using a mechanical model developed in a previous work, is presented for tapered beams subject to even large displacements and small strains. Numerical examples and comparisons with results obtained using other formulas in the literature and non-linear 3D-FEM simulations show how the new formula constitutes an important generalization of the previous ones and is able to provide particularly accurate results.

FEM 시뮬레이션 기반 분로리액터 소음 예측

Electromagnetic-vibration-acoustic coupling simulation based on 3D FEM simulation was carried out to predict the noise under the load condition of a shunt reactor. Electromagnetic forces such as the Lorentz force, magnetostriction and the Maxwell force were identified as major excitation forces. Not only the structure of the shunt reactor, but also the insulating oil and acoustic field areas were considered in the finite element model, and appropriate boundary conditions were applied. For the 10 MVAr/132 kV class shunt reactor, the overall noise levels were compared between measurement and simulation, and exhibited an error of less than 3 dB. Additionally, it is confirmed that the simulated noise radiation characteristics were well matched with real noise radiation characteristics.

A comprehensive 2 Dimensional and 3 Dimensional FEM study of scarf repair for a variety of common composite laminates under in-plane uniaxial and equibiaxial loadings

Due to their potential to recover strength and stiffness with a minimum impact on aerodynamic performance of a damaged structure, scarf repairs are boosted as a viable repair option for primary aero-structures. So far, most of the experimental and numerical studies have been limited to joint specimens and their equivalent 2 Dimensional models and a few number of studies attempted to examine the results using real scarf repair geometry. Suggestions previously made to justify the difference between scarf joint and scarf repair strength and possible solution to diminish the difference are challenged in current work. Here, it is tried to investigate the strengths and shortcomings of 2D scarf joint modelling and their influence on the associated results by promoting 3 Dimensional Finite Element Modelling of complete geometry of the scarf repair. A method to assign material properties to a planar geometry of composite material has been developed that provides the possibility of plane strain, plane stress, and generalized plane strain modelling options of a scarf repair cross section under uniaxial load. Besides, accuracy of scarf joint specimen as a representative to scarf repair to predict load carrying capacity of a circular scarf repair is investigated. The study mainly focuses on 2D and 3D FEM simulation results discrepancies considering the effect of angle ply, cross ply and various stacking sequences of quasi-isotropic laminate under uniaxial and equi-biaxial loads. Results show that the laminate lay-up angles and stacking sequence substantially affect the 2D and 3D simulations agreement. Also, the observed discrepancies in scarf repair and scarf joint results are not limited to the effects of plastic deformation of the adhesive, but it seems the modelling shortcomings greatly affect the results. In overall, the current work demonstrates that for a particular laminate, joint specimen does not represent reasonably a scarf repair. In fact, the load carrying capacity estimated based on joint specimen data can mislead decision making procedure in a way that results in rejection of an eligible repair. To avoid inaccurate strength estimation, a 3D simulation of a scarf repair especially for a load other than uniaxial tension or compression is strongly recommended.

Visualizing undyed microplastic particles and fibers with plasmon-enhanced fluorescence

Despite widespread awareness that enormous consumption of plastics is not sustainable, the global production and use of plastics continue to grow. This generates vast amounts of plastic waste and microplastics, ending up e.g., in the marine environment. There are serious challenges in detecting and measuring microplastics, especially in highly diluted natural samples. Here, a new alternative microplastic detection method based on plasmon-enhanced fluorescence (PEF) was developed and tested using fluorescence microscopy. In particular, gold nanopillar-based substrates, displaying (i) high electromagnetic field enhancement, and (ii) surface superhydrophobicity and high adhesion properties, were utilized to enhance the fluorescence emission signal from microplastics in water samples. The fluorescence microscopy imaging revealed remarkable fluorescence enhancement by the PEF substrates on the microplastic particles and fibers with different sizes of both conventional, low-density polyethylene, and biodegradable poly (butylene adipate-co-terephthalate). The limit of detection and quantification by this method was estimated to be as low as 0.35 and 1.2 femtograms, respectively. The observed fluorescence enhancement of the gold nanopillar substrates for the microplastics was ca. 70 times greater than the case of having the microplastics on a glass substrate. Additionally, 3D FEM simulations were performed to further investigate the system's electromagnetic field distribution near the nanostructures. This new method makes undyed microplastics visible in fluorescence microscopy, even particles and fibres too small to be imaged with conventional light microscopy. This can be a great tool for microplastic research, helping us to detect, study, understand microplastic dynamics in water based systems.

CAD and FEM Modelling of Theoretical Roughness in Diamond Burnishing

Diamond burnishing is a widely used finishing machining that can have a positive effect on both the roughness of cut surfaces and its stress state. This paper is focused on the examination of the theoretical and real roughness of surfaces machined by sliding burnishing. In determining the theoretical roughness, the surface structure created by the pre-burnishing cutting (turning) was also considered. Two different modelling methods were used to obtain theoretical surface roughness data: CAD-modelling and finite element simulation. A method using CAD-based modelling of the machined surface was used to determine the theoretical roughness for both the turning and burnishing processes. However, this previously developed model is not directly applicable to plastic deformation processes such as diamond burnishing, so the principle of the Hertz theory for normal contact of elastic solids was used to calculate the penetration depth of the tool into the workpiece. The 2D FEM simulations were performed in the DEFORM software. To validate the applied modelling methods, real cutting experiments were performed, where the surface roughness values were measured during diamond burnishing experiments with different feed per revolution values. Based on the comparison of both applied modelling methods with real roughness data it can be stated that the theoretical roughness values are well approximated the real data.

Numerical investigation and modeling of residual stress field variability impacting the machining deformations of forged part

Aluminum alloys are widely used for structural parts in the aerospace industry. Those parts are usually machined from rolled plates or forged blanks, and heat treatments are carried out to reach the necessary mechanical properties. Forming and heat treatments induce residual stresses that generate deformations during and after machining because material removal modifies their balance. One major issue in industry is the important variability of the residual stress field in forged blanks. A better knowledge of the residual stress field will enable the definition of better machining strategy to minimize the deformations. In order to understand and manage this variability, a sensibility analysis was performed to investigate the impact of their different potential sources. It relies on a coupling of 2D-FEM and beam model simulations. Then, this work introduces a model reduction technique (by POD and SVD) to build a model of the variability of a stress field and shows how it could be used on the production line.

Applicability of Equivalent Linear Analysis to Reinforced Concrete Shear Walls: 3D FEM Simulation of Experiment Results of Seismic Wall Ultimate Behavior

Applicability of Equivalent Linear Analysis to Reinforced Concrete Shear Walls: 3D FEM Simulation of Experiment Results of Seismic Wall Ultimate Behavior

Improvement of 3D-simulation models based on experiments

The accuracy of manufacturing machines and specially the products of automatic panel benders is continuously improving. Within the last ten years the permissible deviations of the bending angles have been reduced in the specification by 50%, from 1.0° to 0.5°. This accuracy is to be achieved from the first performed bend. In order to further improve and shorten the design process, a parameter identification is carried out based on measurements on the real machine. A good pre-adjustment and tuning of the developed digital twin with respect to the bending process of various sheet metals with a large variety of operating parameters has been derived. In this contribution it is shown how the computation results of the highly efficient 3D-FEM simulation models are matched with the real bending machine in order to derive further improvements.

Crack width verification and minimum reinforcement according to EC 2: Current model with specifications in Germany and Austria vs proposal for revision

AbstractLimiting crack widths to an acceptable level and determining the required minimum reinforcement are important tasks in the design of reinforced and prestressed concrete structures. Experience with different types of structures, ranging from watertight concrete structures to prestressed concrete bridges, shows that the concept currently applied in Germany and Austria is very effective and that significant changes are not necessary. The current draft for the revision of the EC2 (prEC2), however, presents a new concept for crack width verification and minimum reinforcement. In contrast to the concept currently used in Germany and Austria, this new concept is based more on the analysis and good reproduction of observations made in laboratory experiments and takes less account of the mechanical relationships of reinforced or prestressed concrete after cracking. For this purpose, numerous empirical factors are introduced which not only complicate the understanding but also the application in practice. However, an improvement in the accuracy of the crack width prediction is not achieved and the minimum reinforcement is significantly underestimated, especially for prestressed cross sections and thick members. In this article, the new concept set out in prEC2 is explained in detail. Its main weaknesses and contradictions are discussed by a comparison with the concept currently applied in Germany and Austria as well as detailed analysis of 2D FEM simulations with discrete cracks and adequate regard of the bond stress‐slip relationship at the reinforcement‐concrete interface. This should provide the basis for a factual discussion before the introduction of prEC2 into practice.

Effects of pillar design on the thermal performance of vacuum-insulated glazing

Vacuum-insulated glazing (VIG) with a low-emittance coating has a great market potential as an effective transparent insulator. The thermal insulating performance of VIG is determined by its design, including material selection and configuration of different components. Thermal conductance of the vacuum gap as a transport bottleneck is one of the primary factors controlling the thermal transport across VIG. In particular, because support pillars provide the main thermal transport channels across the vacuum gap, increasing the pillar thermal resistance is a key strategy for creating effective thermal insulation while maintaining the vacuum space. In this research, the effects of various pillar design parameters, such as thermal conductivity, geometry, and arrangement, on the VIG thermal performance were comprehensively investigated via the finite element method. In addition, analytical models for thermal transport were examined and thermal conductance across the VIG unit was experimentally measured for validation. The pillar design parameters, especially the height, shape, spacing, and arrangement of the pillars, showed significant effects on the thermal performance of VIG. This research also shows that the smaller contact area for horizontal pillars can effectively decrease the heat loss by more than 30%. Because current VIG analytical equations of thermal performance are only applicable to cylindrical pillars, an analytical equation that can better describe the thermal performance of rectangular parallelepiped pillars is presented, along with a discussion about the mechanism of thermal transfer for different pillar shapes. Thermo-mechanical analyses based on 3D FEM simulations can provide valuable insights into the effect of various design parameters on the overall performance the VIG, allowing for the development of an optimal VIG design.

Experimental validation of ultra-shortened 3D finite element electromagnetic modeling of three-core armored cables at power frequency

Due to recent advances, the numerical analysis of submarine three-core armored cables can nowadays be developed through the finite element method (FEM) in a small slice of the cable. This strongly reduces the computational burden and simulation time. However, the performance of this ultra-shortened 3D-FEM model is still to be fully assessed with experimental measurements. This paper focuses on this validation for an extensive variety of situations through the experimental measurements available in the specialized literature for up to 10 actual cables. In particular, it deals not only with relevant calculations at power frequency, like the series resistance and inductive reactance or the induced sheath current, but also with other aspects never analyzed before through 3D-FEM simulations, such as the zero sequence impedance, the magnetic field distribution around the power cable, as well as side effects due to the nonlinear properties of the armor wires. All this considering different armoring and sheath bonding configurations. Results show a very good agreement between measured and computed values, presenting the ultra-shortened 3D-FEM model as a suitable tool for the analysis and design of three-core armored cables, and opening the possibility to reduce the need of extensive experimental tests in the design stage of new cables.

The Deformation Analysis of a Deep Frame Top-Down Excavation in Downtown Shanghai Based on the 3D FEM

The deformation and environmental influence of the pit excavation in downtown is very important. A 3D FEM analysis is conducted to understand the deformation of a 13.9 to 15.2 m deep excavation with an in-plane dimension of about 189 m width and 251 m length constructed by the frame top-down method (FTDM) in the soft clay region in the Shanghai metropolitan area. The field monitoring results indicate that the magnitudes of wall deflections and ground settlements, along with the column’s uplift difference, are relatively small, which are below the specified protection levels, and that the FTDM is feasible as one of the extralarge excavation construction methods. It is reasonable to predict wall deflection by 3D FEM simulation with qualitative comparison between the simulated column uplifts and the measured data, yet the prediction of the settlement distribution is of no satisfaction. This project studied in this paper not only serves as a special case study calibrated and verified by numerical tools but also provides insights into the design and construction of an extralarge deep excavation using the frame top-down method in soft soils and metropolitan environment.

Analysis and Experiment on the Levitation Force and Thrust Force Characteristics of a Permanent Magnet Electrodynamic Wheel for Maglev Car Application

The traditional permanent magnet electrodynamic suspension (PMEDS) structure has a high cost and low lift to drag ratio caused by sizeable magnetic resistance, which limits its widespread use. Hence, an annular Halbach structure of permanent magnet electrodynamic wheel (EDW) is studied in this paper, which is able to convert the magnetic resistance into the thrust force and avoid extra energy consumption, thus have the potential to be applied into the maglev car system. This paper established an experimental platform to measure the levitation force and thrust force of the EDW, then the force characteristics and variation tendencies were analyzed. Next, to verify the effectiveness and accuracy of the experiment, the comparison between force results from the experiment and that from the 2D FEM simulation were studied. Eventually, this paper lays a foundation for further research on the dynamic levitation characteristics of the EDW. And it provides an individual experimental basis and theoretical guidance for the study of maglev cars based on the PMEDS principle.

Finite element simulation and experimental validation of machining martensitic stainless steel using multi-layered coated carbide tools for industry-relevant outcomes

Martensitic stainless steel is widely used where there is a need for strength, hardness, and corrosion resistance. But the machinability of this steel is difficult because of its poor thermal conductivity, as it leads to high tool wear. Application of coating on the cutting tool is one of the sustainable techniques utilized in improving the machinability of work material. But the problem in the application of the coated tool is the determination of different coating materials and the thickness of coatings, and it usually requires extensive experimental tests. Therefore finite element modelling has proved to be one of the important techniques which can be employed in evaluating the machining performance of coated cutting tools. In the current work, oblique cutting experiments, 2D, and 3D FEM simulations have been performed while machining the martensitic AISI 420 steel using the multi-layered (TiN-TiCN-Al2O3-TiN, TiN-Al2O3-TiCN-TiN) coated carbide tools and uncoated carbide tool. A tabular data material model has been utilized to model the work material. Initially, the simulation results of tangential forces obtained using 2D FE and 3D FE machining models are validated with the experimental tangential forces at a feed rate (f) of 0.14 mm/rev, depth (d) of 0.3 mm, and cutting velocity (V) of 230 m/min. It has been observed that a maximum error of 59.10% in the tangential force has been observed using the 2D FE machining model and experimental results, while a maximum error of 4.05% has been observed using the 3D machining model and experimental results. Thus it indicates that the 3D FE machining model is more suitable in the prediction of machining responses. The 3D FE machining model has been further validated with the experimental results in terms of tangential force and feeds force using the different coated and uncoated cutting tools at varying feed rates of 0.14, 0.18, 0.224, and 0.25 mm/rev and at depth d = 0.3 mm, cutting speed V = 230 m/min. A maximum error of 13.97% in the tangential force and 5% in the feed force is observed at different cutting conditions. The validated model has been further utilized to examine the influence of tool coatings and cutting parameters on the effective stress, cutting temperature, cutting power, and tool temperature. The developed 3D FE model indicates that the better machinability of martensitic AISI 420 steel can be achieved using the multi-layer TiN-TiCN-Al2O3-TiN coated tool in terms of reduction in cutting temperature, effective stress, and power consumption.

Free vibration and buckling characteristics of functionally graded beams with triply periodic minimal surface architecture

This work presents models to studies the free vibration and buckling characteristics of functionally graded porous (FGP) beam with triply periodic minimal surfaces including Primitive, Diamond, IWP, and Gyroid using Euler’s beam theory. The models take into account the effect of the neutral axis dislocation during both vibration and buckling mode. The porous density is considered to be functionally graded along the vertical direction following the practical fabrication of architected structures. The effective stiffness is proposed in form of the three-degree polynomials and their coefficients are found by fitting the discrete data from three-dimensional finite element method (3D FEM) simulation of architected TPMSs with a wide range of porosity. The condition of gradient index is derived based on the power rule to make this work practical. 3D FEM simulations for FGP beam are carried out to validate against the present model in terms of natural frequency and neutral axis deviation to mid-plane with good agreements observed. It is found that three-degree polynomial is a good form to express the effective stiffness over the large range of porosity. In addition, the gradient index, beam dimension, architected material types, and base materials are found to affect significantly the free vibrational and buckling behaviors of beam.

Analytical design and experiment of radial inductive displacement sensor with full-bridge structure for magnetic bearings

In magnetic bearing systems, the air gap between the stator and the rotor is generally measured with an eddy current displacement sensor. However, the inductive displacement sensor (IDS) is a preferred choice due to its structural consistency with magnetic bearings, which contributes to a compact system design. While most of the reported IDS research studies are based on three-dimensional finite element method (3D FEM) simulation and the IDS of such studies is designed with a half-bridge structure, in this paper, a higher sensitivity IDS with a full-bridge structure is proposed. To optimize the response of the sensor, an accurate theoretical analysis method is presented for the sensor based on the Schwarz-Christoffel transformation, which is used for compensating fringe effects of sensor inductance. Compared to traditional 3D FEM simulation, fast sensor design and optimization can be achieved with the proposed method. Experimental results agree well with theoretical predictions. The sensitivity of the proposed sensor is nearly 15.5 mV/μm, and the displacement resolution is better than 1 µm.

3D-FEM Simulation of Hot Rolling Process and Characterization of the Resultant Microstructure of a Light-Weight Mn Steel

Computational simulation has become more important in the design of thermomechanical processing since it allows the optimization of associated parameters such as temperature, stresses, strains and phase transformations. This work presents the results of the three-dimensional Finite Element Method (FEM) simulation of the hot rolling process of a medium Mn steel using DEFORM-3D software. Temperature and effective strain distribution in the surface and center of the sheet were analyzed for different rolling passes; also the change in damage factor was evaluated. According to the hot rolling simulation results, experimental hot rolling parameters were established in order to obtain the desired microstructure avoiding the presence of ferrite precipitation during the process. The microstructural characterization of the hot rolled steel was carried out using optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was found that the phases present in the steel after hot rolling are austenite and α′-martensite. Additionally, to understand the mechanical behavior, tensile tests were performed and concluded that this new steel can be catalogued in the third automotive generation.