Finite Element Methods Research Papers (original) (raw)

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- Finite Element Methods, Response Surface Methodology, Finite Element, Optimization Problem

This paper presents a fast and interesting chaining method for ultrasonic shot peening that allows a quick prediction of the deformed shot peened part from the ultrasonic shot peening process parameters. A simulation of the shot dynamics is done using the exact process parameters, in order to obtain the impact velocity field on the peened surface. This field is then used as an input data for an analytical residual stresses model to predict the induced residual stress field in the sample. The latter is then fed to a Finite Element Method model as an initial condition for an elastic equilibrium calculation to predict the deformation of the part. This allows a complete and fast chaining from the process parameters to the deformed shot peened component. This approach has been applied to an Almen strip. Experimental and numerical data of the strip curvature have been compared and show very promising results.

Two original numerical techniques are developed for the finite element (FE) transient analysis of induction and permanent magnet motors operating in demanding aerospace applications. The first technique is the electromagnetic and thermal analysis weak coupling using a multiple slices 2D FE model. The advantage of the specific technique is the representation of complex actuator geometries including skewed magnets and winding ends, by using a low computational cost 2D model while taking into consideration temperature dependent material attributes. The second technique consists in the development of properly defined boundary conditions for the emulation of the cooling housing of actuators. Those boundary conditions are applied at the outer surface of the actuators in contact with the housing and eliminate the need of modeling complex 3D geometries of highly integrated actuator housings.

Analytical expressions correlating the volumetric flow rate to the inlet and outlet pressures are derived for the time-independent flow of Newtonian fluids in cylindrically-shaped elastic tubes using a one-dimensional Navier-Stokes flow model with two pressure-area constitutive relations. These expressions for elastic tubes are the equivalent of Poiseuille and Poiseuille-type expressions for rigid tubes which were previously derived for the flow of Newtonian and non-Newtonian fluids under various flow conditions. Formulae and procedures for identifying the pressure field and tube geometric profile are also presented. The results are validated by a finite element method implementation. Sensible trends in the analytical and numerical results are observed and documented.

- by Taha Sochi
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- Finite Element Methods, Fluid Mechanics, Fluid structure interaction, Fluid Dynamics

1M. Tech student, Civil-Structures, Maharashtra Institute of TechnologyWPU, Pune, M.H. India 2HOD, Civil-Structures, Maharashtra Institute of Technology-WPU, Pune, M.H. India... more

1M. Tech student, Civil-Structures, Maharashtra Institute of TechnologyWPU, Pune, M.H. India 2HOD, Civil-Structures, Maharashtra Institute of Technology-WPU, Pune, M.H. India ---------------------------------------------------------------------***-------------------------------------------------------------------ABSTRACT: Beam column joints in concrete framed structure have been identified as critical member for transferring forces and bending moments between beams and columns. The change of moments in beam and columns across the joint region, under loadings, induces high shear force and stresses as compared with other adjacent members. The shear failure caused is often brittle in nature which is not an acceptable structural performance. Retrofitting enhances the moment carrying capacity of joint. Often beam column joints need to be strengthened. Author proposes use of ferrocement for retrofitting as wrapping technique, cost effective alternative to costly FRP wrapping technique. In...

- by Philippe Conraux
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- Engineering, Finite Element Methods, Finite element method, Finite Elements
- by Muhammad Zulkifli
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- Electrical Engineering, Finite Element Methods, FPGA, Finite element method
- by Timo Tarhasaari
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- Engineering, Finite Element Methods, Problem Solving, Power Transmission

An finite element method of spur gear linear stattic analysis with SimXpert

One way of computing the macroscopic behavior of a material sample with complex microstructure is to construct a ﬁnite element model based on a micrograph of a representative slice of the material. The quality of the results produced with such a model obviously depends on the quality of the constructed mesh. In this article, we describe a set of routines that modify and improve the quality of a 2D mesh. Most of the routines are guided by an eﬀective element ‘‘energy” functional, which takes into account the shape quality of the elements and the homogeneity of the elements as determined from an underlying segmented image. The interfaces and boundaries in the image arise naturally from the segmentation process. From these routines, we construct a close-to-automatic mesh generator that requires only a few inputs, such as the linear sizes of the largest and smallest features in the micrograph.

- by Valerie Coffman
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- Microstructure, Finite Element Methods, Mesh generation, Material Science
- by G. Hrkac
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- Engineering, Magnetic Recording, Finite Element Methods, Numerical Analysis

Contact forces between two spheres are computed, including the contact pressure (normal) and the frictional stress (tangential) using a finite element method (FEM). A CAD model of a part of a sphere was developed. A mesh was created using ANSYS® Solid 186, 20-Noded hexahedral element and analyzed for its sensitivity. ANSYS® Contact 174 and Target 170, 8-Noded surface elements were used. Contact pressure and frictional stress contours were calculated by varying the displacements. Normal and Tangential contact forces were computed by integrating contact pressure and frictional stress over the contact surface. The values obtained for thenormal force were compared with the non-linear spring model as given byHertz [1]. Similarly values of the tangential force were compared with themodel of Mindlin and Deresiewicz (MD) [2]. The FEM results were found tobe in agreement with the models.

- by Hassan Abbas Khawaja
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- Finite Element Methods

The purpose of this work is to discuss the tulip contact behavior during mechanical and electrical simulations in a Finite Element Method (FEM) environment using ANSYS and COMSOL software. During the simulations, the full contact movement was analyzed. During the contact movement, the individual behavior of the contact components was taken into consideration. The motion simulation was carried out at different velocities and forces acting on the contact. The obtained results were compared to each other and discussed. Relatively, the angles of the contact surfaces to each other were also changed, which meant that we could conduct a more in-depth analysis. The other approach of simulation research was a field analysis of physical phenomena occurring in the tulip contact. This analysis was performed in COMSOL Multiphysics. Parametric analysis allowed an observation of the electric field in the tulip contact at different contact distances with respect to each other. This work is importan...

- by Lukasz Kolimas
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- Engineering, Materials Science, Finite Element Methods, Energy

Transformer design optimization is determined by minimizing the transformer cost taking into consideration constraints imposed both by international specifications and customer needs. The main purpose of this work is the development and validation of an optimization technique based on a parallel mixed integer nonlinear programming methodology in conjunction with the finite element method, in order to reach a global optimum design of wound core power transformers. The proposed optimization methodology has been implemented into software able to provide a global feasible solution for every given set of initial values for the design variables, rendering it suitable for application in the industrial transformer design environment.

- by Yifan Guo
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- Finite Element Methods, Packaging, Finite element method, Finite Element
- by R. Hertel
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- Engineering, Finite Element Methods, Mesh generation, Finite Element

Vertical cylindrical vessel-chambers as a part of coal — drying plants, whose purpose is to collect wastewater, are supported at 3 points in upper dish head area and are made of fine-grained Mn steel plates, joined by welding. Significant thinning and leaking in upper dish head area of the vessel occurred due to original design provoking an intensive abrasion, cracking and rupture. After reconstruction, in the upper zone of cylindrical shell, two new joints were made in sity by manual arc welding, with subsequent, local post-weld heat treatment. However, cracks appeared firstly in new welded zones in radial and axial joints, and then in zones of openings. Later, the similar failure features began to appear in the area of original welded joints. All of these cracks were repaired by properly specified technology. Unfortunately, after some period of exploitation the initiation of new cracks was observed, at first by the visual inspection. This problem was detected in the repaired areas...

- by Gordana Bakic
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- Materials Science, Finite Element Methods, Metallurgy, Heat Treatment

Geosynthetic-reinforced soil segmental retaining walls are now an economical solution. The design of these structures is carried out according to the Association of State Highway and Transportation Officials or the Federal Highway Administration design guidelines, which are based on the limit equilibrium approach. Many experimental, analytical, and numerical studies have identified several sources of conservatism in these design guidelines. This article focuses on a numerical study undertaken using the finite difference code Fast Lagrangian Analysis of Continua in 3 Dimensions (FLAC3D), to investigate the influence of facing batter angle, soil/facing interface friction angle, and backslope angle on the behavior of geosynthetic-reinforced soil segmental retaining walls. The numerical results show that the design guidelines lead to overly conservative design where the soil/facing interface is rough and/or the backslope is present.

- by Mekki Mellas
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- Civil Engineering, Finite Element Methods, Geotechnical Engineering, Retaining Wall

Engineering codes are a key method to guide designs to safe and reliable outcomes. Many such codes have prescribed calculations where the user provides specific inputs in a series of calculations, often using charts or tables, to get specific outputs. The design margins, units, and underlying theory are not always apparent. Engineering codes may not be suitable for reverse engineering an incident or providing a failure prediction. This article examines a criminal negligence case in which an initial forensic analysis incorrectly applied the ASME Pressure Vessel Code to use Finite Element Analysis (FEA) of a failed pressure vessel section. The flaws in the original analysis were revealed by applying reverse engineering using conventional stress calculations and understanding basic material science. This emphasizes the need to understand the underlying theories with both engineering codes and numerical modeling. Subsequent FEA provided an accurate analysis report that was successfully used in court. These same methods can be applied to many other engineering codes and standards. "Although most people do not realize it, standards and the methods used to assess conformity to standards are absolutely critical. They are essential components of our nation's technology infrastructure-vital to industry and commerce, crucial to the health and safety of Ameri-cans, and basic to the nation's economic performance 1 ."

Critical point is a factor that causes chassis fatigue failure. In this study, critical
buckling load analysis of truck chassis with arc-length method and the effect of
replacing conventional steel with two stainless steels in critical point of truck chassis
have been investigated. critical point analysis of stress that may cause the fatigue
failure, the FE software, ABAQUS, is employed. The obtained results from the linear
analysis of buckling showed that changing of the chassis materials did not bring about
considerable changes in the values of critical loads. Post buckling response showed
that the imperfection of very small values causes a significant decrease of the critical
buckling loads. These reductions make stressful points in chassis. Investigation showed that when conventional steel is used in chassis, the amount of displacement and stress is critical in Stressful points. This amount of displacement and stress can cause fatigue failure in chassis and reduce the longevity of chassis.

- by ehsan hedayati
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- Finite Element Methods, Automotive Engineering

A generalized macroscopic representation of electrical steels used in transformer manufacturing industry is developed. The proposed representation is specifically formulated for integration in the finite element method. Usage of the specific technique enables the accurate evaluation of electromagnetic field distribution of transformer cores under heavily saturated conditions. Advantages over conventional techniques include numerical stability, numerical accuracy, and reduction of iterations of the Newton–Raphson method.

- by Oszkar Biro
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- Engineering, Finite Element Methods, Differential Equations, Finite Element Analysis

Computer modelling and simulation of the the quadcopter body had been investigated in this article. For the modelling of a body the Fusion 360 software had been used. In the first stage the geometrical form was taken a simple prismatic form. After analysing the load-stress distribution using finite element method an optimized construction of a body have been designed.

- by Anar Abdurahmanli and +1
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- Mechanical Engineering, Structural Engineering, Finite Element Methods, Solid Mechanics

As Additive Manufacturing (AM) continue to evolve, components can be improved to reduce their overall weight while increasing efficiency. In racing in particular, there is a strong incentive for maximally optimized parts, as sometimes only a few seconds decide between victory and defeat. This paper shows the advantages of Additive Manufacturing in the production of components with complex geometries such as aerodynamic spoilers for vehicles. Here, AM enables the use of bionically inspired structures which make these parts stiff and light at the same time while meeting the load profile (e.g. for the core structure of a wing). Therefore, structure and flow analysis based on the aerodynamic load is carried out and the results converted into algorithms to particularly compress the inner structure in highly stressed areas. The algorithm is a proprietary development that combines data from various software and applies the results to given component geometries simulating bionic structures.

- by Dominique Lehmon and +1
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- Finite Element Methods, Additive Manufacturing, Automotive Engineering

In a nonuniform magnetic field a force acts on ferromagnetic particles, which results from the mutual reaction between the induced magnetic moment in a particle and applied external magnetic field. This phenomenon is named magneto-phoresis, and is used in a various commercial and industrial processes for, among others, for separation of solid magnetic particles suspended in fluids. There are two methods for calculating forces acting on a magnetic particle placed in a magnetic liquid: the first is an equivalent dipole method and the second method is based on Maxwell's stress tensor. Both of these forces can be used in hyperthermia based on magnetic fluids supplied to the patient's body via blood. These forces should cause the placement of ferromagnetic microscopic particles in an adequate place in the patient's body, and then they should be used to produce a heat that interacts with the tumor. These two methods are compared in terms of accuracy and parameters that affect their accuracy. This article will discuss two mentioned methods for calculating forces acting on a particle in a magnetic fluid.

- by Piotr Gas
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- Finite Element Methods, Hyperthermia, magnetophoresis, Magnetic Particles Placement

Little scientific information about dental restorative materials has been available until recently. Prior to this knowledge, the use of these materials was entirely an art, and the only tasting laboratory was the mouth of the patient. Today, despite the availability of the sophisticated technical equipment and development of standardized testing methods for evaluating the mechanical and thermal properties of restorative materials, this testing sometimes still occur on the mouth of our patients. The present work has considered and compared the essential mechanical and thermal properties of some of the most widely used restorative materials. The behaviour of these materials when used to filled class I cavity on mandibular first molar tooth, under the combinations of different thermal and structural loads were analysed using ANSYS (Work bench 15.0). Amalgam, Composite, and Gold alloys materials were considered for this work, the results obtained from ANSYS analysis showed that, the maximum deformation occurred at the occlusal surface, specifically on the filling material and increases towards the other four surfaces (mesial, buccal, lingual and distal surfaces) and the roots, while the equivalent (Von-Mises) stress was depicted along the cervical line (a border line between crown and roots) and distributed towards both the crown and the roots. 35 trials were made and the values for the maximum deformation and von-Mises stress were both plotted against the temperature and structural load using Qtiplot software, and the final result showed that; Gold alloy and composite materials has the least and highest values of both deformation and von-Mises stresses respectively.

- by Abdulfatah A Yusuf
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- Mechanical Engineering, Finite Element Methods, Machine Design

Increase in use of power electronics in power system addressed power quality problems. Converters are widely used in industrial area for different application. They are non-linear devices and degrade power quality of system. In this paper, 12 – pulse ac – dc power supply is taken as non-linear load example. Power supply, here discuss is use in low voltage, high dc current application. High dc current is generated by connecting four M3 converters in parallel. Phase-shifting transformer is also introduce for require phase displacement. Converter can affect power quality in terms of inject harmonics and decrease power factor. It can be used as dynamic load; therefore, it is necessary to evaluate active and reactive power for different loading condition. This paper represents assessment of power quality for such system.

Despite the generally inferior clinical performance of acetabular prostheses as compared
to the femoral implants, the causes of acetabular component loosening and the extent to
which mechanical factors play a role in the failure mechanism are not clearly understood
yet. The study was aimed at investigating the load transfer and bone remodelling around
the uncemented acetabular prosthesis.
The 3-D FE model of a natural right hemi-pelvis was developed using CT-scan data. The
same bone was implanted with two uncemented hemispherical acetabular components,
one metallic (CoCrMo alloy) and the other ceramic (Biolox delta), with 54 mm outer
diameter and 48 mm bearing diameter. The FE models of the implanted pelvis
(containing ~116000 quadratic tetrahedrals) were generated using a submodelling
approach, which were based on an overall full model of implanted pelvis (containing
~217600 quadratic tetrahedrals) acted upon by hip joint force and twenty one muscle
forces. The apparent density (ρ in g cm-3) of each cancellous bone element was calculated
using linear calibration of CT numbers of bone, from which the Young’s modulus (E in
MPa) was determined using the relationship, E = 2017.3 ρ2.46 [1].
Implant-bone interface
conditions, fully bonded and debonded with friction coefficient μ = 0.5, were simulated
using contact elements. Applied loading conditions consist of two load cases during a gait
cycle, corresponding to 13% and 52% of the walking cycle. Fixed constraints were
prescribed at the pubis and at the sacroiliac joint. The bone remodelling algorithm was
based on strain energy based site-specific formulation [2]. The FE analysis, in
combination with the bone remodelling simulation, was performed using ANSYS FE
software.
The predicted changes in peri-prosthetic bone density were similar for the metallic and
the ceramic implant. For debonded implant-bone interface, stress shielding led to ~20%
reductions in bone density at supero-anterior, infero-anterior and posterior part of the
acetabulum (Fig. 1). However, bone apposition was observed at the supero-posterior part
of the acetabulum, where implantation led to ~60% increase in bone density (Fig. 1). The
effect of bone resorption was higher for the fully bonded implant-bone interface, wherein
bone density reductions of 20 – 50% were observed in the cancellous bone underlying the
implant (Fig. 1), which is indicative of implant loosening over time. However,
implantation led to an increase in bone density around the acetabular rim for both the
interface conditions (Fig. 1). These results are well corroborated by the earlier studies
[3,4]. Implantation with a ceramic component resulted in 2 – 7% increase in bone density
at supero-posterior part of the acetabulum as compared to the metallic component, for the
debonded interface condition. Considering better wear resistant properties and absence of
metal ion release, results of this study suggest that the ceramic component might be a
viable alternative to the metallic prosthesis.

- by Kaushik Mukherjee and +1
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- Finite Element Methods, Orthopaedic Implants, Orthopaedic Biomechanics, Bone Remodelling
- by Jacek Gieras
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- Engineering, Design, Finite Element Methods, Finite element method

Currently, there are a lot of powerful FEM packages which are used for different types of analysis of structures. However, using these softwares for assessment of seismic safety and strengthening of historical masonry buildings are envolved with some problems. Complex building geometry, low information about physical and mechanical properties of materials, lack of precise information about composing material of internal parts of thick elements, prohibition of execution of destructive tests on these buildings, consumpsion of considerable cost and time for analysis process are some of the problems for engineers and researchers working professionally on numerical modelling of historical buildings.
Simplified Kinematic Limit Analysis (SKLA) is a powerful method for the analysis of historical buildings. Historical masonry buildings subjected to earthquake show in most cases local failure mechanisms rather than global failure mechanisms due to the lack of integrity of structure. For this reason, SKLA method is recommended for strengthening of historical masonry buildings in Italian O.P.C.M.3431 ordinance. Simplified kinematic limit analysis of a structure includes a series of limit analysis that check the stability of different specific failure mechanisms involving the equilibrium of macro-elements. This kind of analysis stemed from the fact that structural masonry constructions normally collapse due to a local failure mechanism. Applied rules in this method are based on virtual work principle. Four overturning and four in plane collapse mechanisms were devised and analyzed for seismic safety assessment of structure in SKLA method.
In this paper, this method (SKLA) capability for assessing the seismic safety of Tabriz Alisha Citadel is investigated. For this, the results of analysese of this building by two methods of SKLA and FEM are compared. The comparison of the results of two methods has shown acceptable accordance. High analysis speed and being free of precise mechanical properties of the buildings material are main features of SKLA method. However, tracing the magnitude of stresses and deflections in different points, revealing collapse time and sequence of fracture of walls are main features of FEM. It seems that the SKLA can be utilized as a high speed and low cost tool for primary assessment of seismic safety of masonry buildings.
From that result, it was concluded that the structure is not safe. While the gravity capacity of the structure is high, its lateral resistance to equivalent static loading is not enough.

- by Majid Pouraminian and +1
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- Finite Element Methods, Seismic safety assessment

Convolving the output of Discontinuous Galerkin computations with symmetric Smoothness-Increasing Accuracy-Conserving (SIAC) filters can improve both smoothness and accuracy. To extend convolution to the boundaries, several one-sided spline filters have recently been developed. This paper interprets these filters as instances of a general class of position-dependent (PSIAC) spline filters that can have non-uniform knot sequences and skip B-splines of the sequence. PSIAC filters with rational knot sequences have rational coefficients. For prototype knot sequences , such as integer sequences that may have repeated entries, PSIAC filters can be expressed in symbolic form. Based on the insight that filters for shifted or scaled knot sequences are easily derived by non-uniform scaling of one prototype filter, a single filter can be re-used in different locations and at different scales. Computing a value of the convolution then simplifies to forming a scalar product of a short vector with the local output data. Restating one-sided filters in this form improves both stability and efficiency compared to their original formulation via numerical integration. PSIAC filtering is demonstrated for several established and one new boundary filter.

In this paper a robust three-dimensional (3D) finite element (FE) anisotropy model is introduced based on a particular scalar potential formulation. The specific 3D FE model is suitable for the accurate evaluation of the peak flux density distribution and no load loss of one-phase and three-phase wound core distribution transformers. The accuracy of the proposed 3D FE anisotropy model is validated by local flux density and no load loss measurements.

We use a texture component crystal plasticity ﬁnite element method for the simulation of plane strain compression (maximum thickness reduction 95%) of a ferritic stainless steel (X6Cr17, AISI 430, 1.4016). The method incorporates the graded hot band texture of the starting material and predicts the development of the orientation distribution during forming in the surface and in the center layer considering 24 slip systems.

- by Jonas De Basabe
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- Finite Element Methods, Numerical Analysis, Dispersion, Spectral element methods
- by alvaro sanchez
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- Engineering, Distributed Computing, Finite Element Methods, Magnetic Materials
- by E. Cardelli and +1
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- Engineering, Finite Element Methods, Magnetic Materials, Finite element method

There have been numerous publications on unreinforced masonry construction in the literature; however, there is a lack of publications on the condition assessment of existing unreinforced masonry façades for disturbances due to nearby subway construction. To fill this gap, this paper presents a study in which a 5-story historical building with unreinforced masonry façade experiences inward and outward deformations perpendicular to the plane of wall due to nearby subway construction. The performance of the unreinforced masonry façade is examined under wind load combinations. For this, a finite-element (FE) model is built in ANSYS software to conduct a stress analysis of the brick façade. The results revealed that the tensile stresses exceeded the tensile stress limit at several locations; therefore, a structural remediation is required. A structural retrofit is proposed to tie the façade wall to the floor diaphragms with steel anchor rods at specific stories. Another FE model is built to represent the remedies proposed for stabilizing the façade wall. The results show that all stresses are within the limits, indicating that the structural solution for the remediation is appropriate. As a result of this study, the proposed remediation was implemented at the building, and the structure has been in good structural condition without any complaints, even after the subway construction was completed and the subway line was in operation.

Представлена инженерная методика исследования тепловых режимов за-крытых асинхронных двигателей с короткозамкнутым ротором, эксплуатируемых в широком диапазоне частоты вращения при основных системах воздушного охлаждения. Выводятся аналитические выражения, позволяющие рассчитать: превышение температуры обмотки статора; допустимую нагрузку при изменении интенсивности охлаждения; значения коэффициентов влияния потерь. Уточняется формула расчета сервис-фактора электродвигателя. Расчетный аппарат развивает метод эквивалентных потерь на класс частотно-регулируемых двигателей.

The microstructure of dual phase steels can be compared with a composite composed of a matrix of ferrite reinforced by small islands of martensite. This assumption has been used in several attempts to model the mechanical properties of dual phase steels. However, recent measurements show that the properties of the ferrite phase change with distance from the martensite grains. These measurements showed that the grains of the ferrite phase are harder in the vicinity of martensite grains. As a consequence of this local hardening eﬀect,the ferrite phase has to be considered as an inhomogeneous matrix in modeling dual phase steels. This experiment inspired the idea thatlocal hardening is caused by geometrically necessary dislocations. The idea is investigated experimentally and numerically in the presentanalysis, which for the ﬁrst time leads to good agreement with experimental observations of the mechanical stress–strain behavior

- by Dierk Raabe
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- Microstructure, Finite Element Methods, Micromechanics, Mechanical properties

"Tumour identification is a critical step in robot-assisted partial nephrectomy (RAPN) during which the surgeon determine the tumour localization and resection margins. To help the surgeon in achieving this step, our research work aims at leveraging both pre- and intra-operative imaging modalities (CT, MRI, laparoscopic US, stereo endoscopic video) to provide an augmented reality view of kidney-tumour boundaries with uncertainty-encoded information. We present herein the progress of this research work including segmentation of pre-operaitve scans, biomechanical simulation of deformations, stereo surface reconstruction from stereo endoscopic camera, pre-operative to intra-operative data registration, and augmented reality visualization"

- by Ivan Figueroa Garcia
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- Medical Imaging, Finite Element Methods, Biomechanics