FEM Modelling and Numerical Simulation Research Papers (original) (raw)

This paper presents a numerical analysis of a short circular hollow column using ABAQUS software. Circular hollow sections have high structural efficiency due to lack of major or minor axes. Such sections are also effective in areas with limited spaces.This paper provides an examination of their performance under axial loading using numerical analysis

With the development of the modeling and computer technology, the scale of mate-
rial has been expanded from macro- to micro-, also from micro- to nanoscale. The
development of molecular modeling tools to describe and predict the mechanical
properties of structural materials reveals to be of undeniable practical importance.
At the nanometer scale, anisotropy is the consequence of differences in the direc-
tional arrangements of atomic structure, the force between atoms, such as van der
Waals force, typical Coulomb force, and other forces.
Till early twenty-first century, the approximate solution of the Schrödinger equa-
tion in quantum mechanics field is almost equivalent to the importance of using
Newton’s laws widely to solve classical mechanics problems. Density functional
theory (DFT) as a first-principles theory and a solid band theory in quantum
mechanics has own a great success in linking physical properties and molecular
structure, the calculation with exact accuracy but for low computational efficiency
for macromolecular structure. Molecular dynamics (MD) has obvious advantages
in simulating macromolecular structure, with very high computational efficiency
but for much dependency of atomic potential parameters. Besides, MD method is
limited into a range of structure at atomic scale level and it cannot effectively solve
continuum mechanics problems like practical engineering application using finite
element method (FEM). So we look for a modeling tool so as to further widen the
application fields of nanoindentation simulation with consideration of atomic
forces at nanoscale level. In addition to the tradition of DFT and MD methods
that we briefly introduced above, a so-called AFEM modeling methodology at the
atomic scale (or nanoscale) is further investigated since the macroscopic properties
depend largely on the physicochemical properties of the interatomic bonds.
Nanoscale modeling and mechanical properties by using the density functional
theory (DFT), a so-called atomic finite element method (AFEM), and the classi-
cal molecular dynamics (MD) method are especially concerned according to the
modeling requirement of different crystals structures investigated.
This is a book of a professional and systematic scientific research by Dr. Jia Fu.
This book is committed to model and to calculate mechanical properties (Young’s
modulus especially) of typical anisotropic crystals structures (cubic crystals: CaO
and MgO; hexagonal crystals: CH and calcite; monoclinic crystals: 11 Å tobermorite
and gypsum; others: CNT and graphene; monolithic structures of C▬S▬H (I)
(Ca/Si = 0.67) and C▬S▬H (II) (Ca/Si = 1.67)) by programming with using three
methods above. Omitting the description of these structures’ importance, elastic
moduli are separately calculated by either homogenization or curve fitting of the
linear portion of the stress-strain curve by the corresponding numerical simula-
tions. At the end, nanoindentation experiments, SEM, and nanoindentation simula-
tions are carried out to determine elastic moduli of several phases in cement pastes.
As crystal structures at nanoscale always tend to exhibit anisotropy, our research
objects of typical cement phase structures depending on crystal types and practical
research needs in book are mainly divided into five types: cubic crystals (CaO
and MgO), hexagonal crystals (calcite and portlandite), monoclinic crystals (11 Å
tobermorite and gypsum), monolithic structures: C▬S▬H (I) (Ca/Si = 0.67) and
C▬S▬H (II) (Ca/Si = 1.67), and other crystals structures (CNT, graphene). These
structures are typical constituents of the microscale Portland hydrated cement
paste (HPCP) and their Young’s moduli are needed in a 3D multiscale mortar model.
Nanoscale modeling helps build the bottom-up multiscale model, by which the
accurately independent models of typical structures can be verified by the elastic
moduli obtained at atomic scale, then the needed multiscale model can be estab-
lished. In this book, we mainly focus on modeling and calculating the mechanical
properties of these typical anisotropic crystal structures at nanoscale with a high
efficiency, then determining homogenized elastic moduli of these structures with a
larger scale.
In summary, by identifying relevant parameters using the improved AFEM method
and other computational program, it therefore connects nanoscale modeling and
continuous pattern of deformation behavior from small scales to larger scales.
We believe that our research above will be expanded the existing research and to
provide further detailed parameters of our research objects, thus leads to a certain
practical significance.

Electrically active implants for regenerative therapies (e.g. regeneration of bone tissue or deep brain stimulation for the treatment of motion disorders) are gaining on importance within an aging population. The implants must be replaced during the course of the therapy. Their performance requirements vary from a few microwatts to a few milliwatts and will keep increasing with growing functionality. In order to extend the life of electrical active implants and thus avoid the expensive and risky operations for their replacement, a considerable amount of the implant's energy requirement shall be covered by the conversion of mechanical or thermal body energy into electrical power. In this work, we present a multi-physical model of a miniaturized thermoelectric generator for electrically active implants, which uses temperature gradients in human tissue. Based on this model, we analyze the influence of the geometry and material parameters on the thermal and electrical properties and aim for an optimal transducer design. Furthermore, we use mathematical methods of model order reduction to create an accurate compact model that can be applied within a system simulation.

The numerical methodes are most suitable to the specific task of assessing the mechanical state of the rock mass near longwall face. In particular, the finite element method (FEM). This method makes it possible to reflect in the calculations the initial stress state of the rock masses and their structural features (heterogeneity, layering, the presence of weak interlayer contacts, anisotropy, fracturing, etc.) and mechanical processes that occur during the excavation of coal seams (loss of mass continuity, block formation, hanging and collapse of layers, etc.). The advantage of the FEM is the ability to modeling any forms of connection between stresses and strains, as well as taking into account the interaction of supports with rocks.

The need to reduce electricity consumption by electrical devices, including electric motors, is the reason for the development of new designs. Designers strive to improve operational parameters, including efficiency, using, for example, new types of magnetic materials, new types of stator windings, etc. Currently, in mass production, motor cores are made of punched laminations-punching causes damage of core parts. For motors of relatively large geometrical sizes, this effect is ignored during design. For motors having small dimensions, this negative effect results in a reduction in efficiency, which is mostly small for this type of motor. In this paper, the authors propose a new rapid algorithm based on simple measurements to determine the material characteristics of the damaged material part. Then, using them in the FEM models, they determine the efficiency of motors with various powers and frame sizes. On this basis, the conclusions are formulated, they may be helpful for motor designers.

- by Zbigniew Gmyrek and +1
- •
- Electrical Engineering, Magnetic Materials, Electrical Motors, Efficiency

В диссертационной работе решена актуальная научно-техническая задача прогнозирования проявлений горного давления при проведении выработки и адаптации параметров крепи к изменчивым геомеханическим процессам. В результате анализа состояния горных выработок и методов прогнозирования проявлений горного давления установлено, что выработки проектируют и сооружают в условиях неполной геомеханической информации, поэтому принимаемые решения по их креплению не всегда рациональны, выработки обладают низкой эксплуатационной надежностью, а на их ремонт затрачиваются огромные средства. Усовершенствована комплексная методика шахтных наблюдений, включающая изучение анизотропии прочностных свойств пород, регистрацию смещений пород при помощи контурных и глубинных реперов, оценку нарушенности породного массива вокруг выработки с помощью модернизированного электроемкостного интроскопа. Проведены теоретические исследования зоны влияния выработки в неравнокомпонентном поле напряжений с учетом: критерия, по которому определяется её граница, и погрешности вычисления; исходного напряженного состояния породного массива; формы выработки; площади её поперечного сечения и соотношения высоты и ширины; ориентации выработки относительно направления действия главных напряжений в породном массиве; стадии развития и размеров зоны неупругих деформаций вокруг выработки. Доказано, что в пределах области достоверного моделирования методом конечных элементов площадь дополнительно напряженных элементов связана с площадью зоны разрушения вокруг выработки линейной зависимостью. При этом граничные условия соблюдаются при площади разрушения, которая не превышает 5% от площади расчетной модели, как для выработки круглой формы, так и квадратной (с углами). Дальнейшее увеличение площади разрушенных элементов ведет к потере устойчивости модели. Для установления вида функции влияния забоя решены пространственные упругие задачи о распределении напряжений вокруг выработки круглой и квадратной форм поперечного сечения. Эта функция является множителем к компонентам начального поля напряжений при решении псевдопространственной задачи и изменяется впереди забоя по нелинейной зависимости от 1 до 2, в плоскости забоя имеет скачок до 0,6, а позади забоя возрастает по экспоненте от 0,6 до 1. В результате моделирования зоны разрушения пород вокруг незакрепленной выработки установлено, что для всех форм поперечного сечения выработки зависимость относительной площади зоны разрушения от расстояния до забоя представляет собой нелинейную функцию, зависящую от относительного показателя прочности пород, обобщенного коэффициента бокового распора и реологического параметра и изменяющуюся от нуля в месте зарождения зоны разрушения до некоторого предельного значения, которое функция принимает на границе зоны влияния забоя, определяемой процессом перераспределения поля напряжений. В результате моделирования зоны разрушения пород вокруг выработки, в которой возводится адаптивная крепь с предварительным распором, установлено, что за счет уплотнения разрушенных пород можно уменьшить площадь зоны неупругих деформаций на границе зоны влияния забоя в 1,5-2,5 раза, причем зависимость этой площади от расстояния до забоя, на котором производится распор крепи, имеет минимум, учет которого позволяет объективно назначать рациональные параметры крепи и её распора. На основе установленных закономерностей разработан метод двухэтапного прогнозирования проявлений горного давления. Предварительный приблизительный прогноз реализуется на стадии проектирования выработки на основе неполной геомеханической информации. Текущий прогноз осуществляется при проведении выработки путем сочетания компьютерного моделирования и шахтных измерений. По результатам текущего прогноза корректируется при необходимости геомеханическая модель, устанавливается отсутствовавшая информация и адаптируются параметры крепи к изменчивым геомеханическим процессам.

Tubular pipe structures have been used in various applications-domestic, aviation, marine, manufacturing and material testing. The applications of tubular pipes have been considered greatly in the installation of tubular pipes, marine risers and pipe bending. For the investigation of plastic strains and the mechanical behaviour of a tube under bending, considerations were made utilising an exponent model with assumptions on the plane strain. The bending moment, wall thickness effect, cross-sectional distribution, stresses during bending and neutral layer boundaries were all presented as necessary theoretical formulations on the physics of tubular pipe bending. This model was based on the analytical and numerical investigation. In principle, the application can be observed as the spooling of pipes, bending of pipes and reeling. Comparisons were made on two models developed on the finite element analysis in Simscale OpenFEA, namely the linear-elastic and the elasto-plastic models. Thi...

- by Abiodun Oyetunji
- •
- Mechanical Engineering, Nanoparticles, Inventions, Mechanical Engineering Design

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 using the method of finite elements and starting with the possibilities given by the program system ANSYS in the field of application, research has been performed regarding the analysis of static behavior of a centrifugal pump shaft. The computational analysis of static behavior of shaft using the method of finite elements on the examined model during the phase of projecting, was aiming for a timely sighting of critical spots, in order to avoid possible further malfunction. In this way it is possible to examine validity of the basic solution with no need for making the prototypes. By static behavior analysis, in other words, using the method of finite elements it was shown to which extent can certain conditions of exploitation, created tensions, that is shifted knots, cause difficulties in the whole model performance. Analysis of the static behavior of shaft was performed for two cases with different load: the effect of radial force and the torsion moment. A special attention was...

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.

Turbo Generator foundation is one of the Paramount structures; if not the most one; in power generation plants. For the Turbo Generator foundation design, finite element (FE) is the commonly acknowledged analysis tool in structural engineering field. As the turbine and generator are relatively rigid compared either to the foundation or to the soil in analysis, both machines contributes in the finite element model through their masses applied at their center of gravity. Those elevated masses are connected to the foundation using rigid links / rigid beam elements in order to transfer loads / masses from the machines CG level to the foundation level. Rigid links are usually simulated in the analysis model as beam elements with a large Young's modulus value relative to other elements presented in the model (e.g., 100 times stiffer than the elements they are linked to) [1]. The aim of this paper is to examine study and recommend the most efficient rigid links Young's modulus value and modeling method in order to simulate the actual behavior of the system to reach the optimum dynamic and static analysis results of the Turbo Generator foundation. the analysis result indicates that using Young's modulus for the rigid link equal to ten-thousand-time steel young's modulus provide the most realistic dynamic behavior for the machine foundation.

This paper examines the impact of different pile configurations and geometric parameters on the bearing capacity and the settlement response of a combined pile–raft foundation system utilizing FLAC3D software. The configurations considered were: (1) uniform piles (denoted as CONF1), (2) shorter and longer piles uniformly distributed on the plan view of the raft (CONF2), (3) shorter piles at the center and longer piles at the edge of the raft (CONF3), and (4) longer piles at the center and shorter piles at the edge of the raft (CONF4). In the same framework, different pile diameters and raft stiffnesses were examined. The piles are considered to float in a cohesive–frictional soil mass, simulating the thick cohesive soil deposit found in Addis Abeba (Ethiopia). During simulation, a zero-thickness interface element was employed to incorporate the complex interaction between the soil elements and the structural elements. The analyses indicate that the configuration of piles has a considerable effect on both the bearing capacity and the settlement response of the foundation system. CONF1 and CONF3 improve the bearing capacity and exhibits a smaller average settlement than other configurations. However, CONF3 registers the highest differential settlement. On the other hand, the lowest differential settlement was achieved by the CONF4 configuration; the same configuration also gives ultimate load resistance comparable to those provided by either CONF1 or CONF3. The study also showed that applying zero-thickness interface elements to simulate the interaction between components of the foundation system is suitable for examining piled raft foundations problem.

- by Dr. Costas Sachpazis
- •
- Numerical Modeling, Numerical Analysis, Piles, Piled-Raft Foundations

In this paper we displayed the problematic of modeling, analysis and simulating work process of specific tool used for punching and cutting operations on inner plate of the front car door. Basic principles of treating material with deformations are displayed, to easily understand operations that are performed during the work of the tool. Principles of geometric modeling, application of Boolean operations, parametrized individual standard parts and databases are very important factors for tool modeling. Beside modeling it is very important to calculate the specific parts based on standards which are used in car industry. After geometrical modeling of tool, simulation and work analysis have been performed to control the movement speed of the tool during production. Simulation also enables faster design process for the tool, increases work safety etc.

- by Isad Saric
- •
- Modeling, Modeling and Simulation, Structural Analysis, Simulation

Ch 009: Soil–structure interaction for seismic analysis and design of bridges

The present research intends to study the effects of the seismic soil-foundation-structure interaction (SFSI) on the dynamic response of various buildings. Two methods including direct and Cone model were studied through 3D finite element method using ABAQUS software. Cone model as an approximate method to consider the SFSI phenomenon was developed and evaluated for both high and low rise buildings. Effect of soil nonlinearity, foundation rigidity and embedment as well as friction coefficient between soil-foundation interfaces during seismic excitation are investigated. Validity and performance of both approaches are evaluated as reference graphs for Cone model and infinite boundary condition, soil nonlinearity and amplification factor for direct method. A series of calculations by DeepSoil for inverse earthquake record modification was conducted. A comparison of the two methods was carried out by root-mean-square-deviation (RMSD) tool for maximum lateral displacement and story shear forces which verifies that Cone model results have good agreement with direct method. It was concluded that Cone method is a convenient, fast and rather accurate method as an approximate way to count for soil media.

- by Azadeh Amiri and +1
- •
- Structural Engineering, Soil-Structure Interaction, Abaqus, FEM Modelling and Numerical Simulation

Currently, electric motor manufacturers install a ground and turn insulation capable of withstanding normal operating voltages without exceeding the dielectric strength of the air. If the electric field generated during operation exceeds this characteristic quantity, there are pre-discharge phenomena, which accelerate the degradation of the insulation and therefore lead to a shortening of the useful life of the machine. The main objective of this thesis was to develop a model capable of determining the so-called Partial Discharge Inception Voltage for random-wound machines and to facilitate the design of their electrical insulation system. In addition to this, an in-depth study was carried out on how to improve the qualification process of electric motors and actuators intended for use in the world of More Electric Transportation. First, it was considered how to effectively test the insulation systems of random-wound electrical machines to prove that they are PD-free. Subsequently, ...

The reasons for failure of locally made furnaces in the foundries were as a result of cycles of operating temperatures that they were subjected to, which caused thermal stress and strain on the furnaces. This paper studied the simulation... more

- by Abiodun Abioye and +1
- •
- FEM Modelling and Numerical Simulation

Implementing an effective disaster management, community-based disaster management (CBDM) has become increasingly important in societies facing complex and uncertain disaster risks. CBDM emphasizes community self-reliance, raising awareness of vulnerability and root causes of disasters and developing practical program-solving skills. It is also widely recognized that community-based flood risk communication among residents, regional communities, and administrative authorities is central to effective flood risk management. A clear communication of flood risk ensures the appropriate and effective steps to reduce and mitigate the risk in community-based flood risk management. Flood hazard maps are
also recognized as useful instruments for flood risk management in many other countries. In the case of a
flash flood, it is crucial to examine the evacuation timing and time-space distributions both of flood risk and safety evacuation routs in the community levels. However, very little work is currently available to investigate these issues in the conventional flood hazard maps. This lack of the studies is troubling in implementing the effective community-based flood risk management. The purpose of this study is to investigate
an integrated flood evacuation simulator taking into account the time-space distributions both of flood risk and safety evacuation routs in the community levels. Two-dimensional flood simulations were conducted using an unstructured grid model to consider the detailed land-use in the community level. The flood evacuation simulations using the multi-agent model were also performed to examine the evacuation timing and proper location planning of evacuation refuges. The proposed evacuation simulator would be recognized the useful tools for disaster prevention planning in community levels. This simulator also can be used for disaster education, evacuation planning and training for both the individual and community
levels.
Key Words : Community-based Flood Risk Management, Evacuation, Integrated Model, Hazard Map

- by Natainia Lummen
- •
- Numerical Simulations, Numerical Modeling, Flood Risk Management, Urban Studies

Opsi merupakan suatu kontrak antara penjual opsi dengan pembeli opsi, dimana penjual opsi menjamin adanya hak (bukan suatu kewajiban) dari pembeli opsi untuk membeli atau menjual saham tertentu pada waktu dan harga yang telah ditentukan. Paper ini membahas tentang penentuan harga opsi untuk model Black-Scholes yang berupa persamaan diferensial parsial. Model Black-Scholes tipe Eropa dapat diselesaikan secara eksak, dengan mentransformasikan modelnya ke dalam bentuk persamaan panas. Kemudian, untuk mencari solusi numeriknya, digunakan metode beda hingga Crank-Nicolson.

En este trabajo se realizó un estudio sobre un caso de campo en pozos fracturados hidráulicamente en yacimientos areno-arcillosos, con una disminución importante en su producción de aceite. En los pozos estudiados se sospechó que la integridad de la fractura y su conductividad estaban seriamente degradadas y se consideró su re-fracturamiento. Se detectaron, sin embargo, otras complejidades geológicas y de fluidos que también contribuyeron a la disminución de la producción. Se discuten los resultados de la aplicación, de una nueva metodología para la selección de estos candidatos, a través del análisis dinámico de la presión transitoria para el caso de una fractura de conductividad finita.
Se proporcionan nuevos resultados calculando los parámetros de presión inicial (pi), permeabilidad (k), daño (s), que se utilizan para el diseño del fracturamiento hidráulico; a través de los métodos de la primera y segunda derivada. La metodología incluyó modelos semi-analíticos y numéricos, que permiten explicar la propagación, cierre y longitud final de la fractura apuntalada y total. Fue necesario considerar estas variables para interpretar la presión transitoria y los parámetros durante el diseño. Para diagnosticar y tener un resultado final del primer fracturamiento, se realizaron las pruebas para el ajuste del modelo de yacimiento (condiciones transitorias y presión de yacimiento actual) y para el ajuste del modelo de frontera (condiciones pseudo-estacionarias, reserva original y remanente asociada al pozo). De acuerdo a resultados de campo, mostrados en la literatura (Wolhart et al., 2000, 2007), (Berumen et al., 2000) (Moos et al. 2000) (Zoback, M.D. 2007) se consideró que la producción puede causar rotación de esfuerzos en el área de influencia del pozo y en consecuencia se genera una nueva orientación en la fractura. Esto se tomó en cuenta para los nuevos diseños. (W. John Lee, & Kuchuk, F.)

- by Miguel Angel Vidal Arango and +1
- •
- Reservoir Engineering, Productivity, Reservoir Simulation, Well Test Analysis of Naturally Fractured Reservoir

represents a small but active scientific community in Greece. Being affiliated with the International Association for Computational Mechanics (IACM) and the European Community on Computational Methods in Applied Sciences (ECCOMAS), GRACM has been from the very beginning oriented towards international scientific interaction and cooperation. The GRACM Conferences aim at bringing together the members of the Greek computational mechanics community, domestic and of the diaspora, and colleagues from abroad, mainly from academia.

- by Giorgos Kouzilos
- •
- Polymer Engineering, Heat Transfer, FEM, Heat and Mass Transfer

The losses in European Union distribution transformers are estimated at about 33 TW · h/year, whereas reactive power and harmonic losses add a further 5 TW · h/year. The reduction of distribution transformer no-load loss is particularly important as the ratio of no-load to load losses is nearly three. In this paper, the no load operation of wound-core transformers under sinusoidal and distorted supply-voltage conditions is investigated. For that purpose, a 2-D nonlinear transient finite-element analysis taking into account hysteresis has been developed. The hysteresis model is based on a modified Jiles–Atherton representation, and the proposed analysis is compared to experimental data.

- by Themistoklis D. Kefalas
- •
- Engineering, Electrical Engineering, Harmonic Analysis, Electromagnetism

"The paper deals with the flexural failure of Reinforced Concrete elements under
blast loads. The main topics and results of a PhD thesis are here summarized, whose
aim was to develop theoretical dynamic and energy models capable of evaluating the
dynamic response of R.C. elements under explosive load.
In the original work, models with different levels of complexity were presented, but
for sake of simplicity only the simplest Single Degree Of Freedom (SDOF) system has
been here discussed. Strain-rate effects are also accounted for.
A sensitivity analysis to determine the key parameters in beam response under
blast load has been developed by means of the SDOF model. Results of numerical
simulations obtained in terms of deflection and velocity have been fitted by proper
polynomial least-square interpolation.
Among the various interpolations considering several parameters (peak load,
positive phase duration, slenderness, span length, concrete strength, reinforcement
ratio etc.) slenderness (corresponding to stiffness) and peak load prove to be the most
important parameters, but span length (corresponding to mass) is also a key
parameter. Other variables such as concrete strength and reinforcement ratio do not
seem to have a high correlation with results.
Lastly some suggestions for blast-resistant bridge design are presented."

- by Flavio Stochino
- •
- Civil Engineering, Structural Engineering, Concrete, Structural Dynamics

This paper proposes to find the significant geometrical length of the saxophone mouthpiece, to compare the acoustical properties of shape variations. For this purpose I created a parametric model of a mouthpiece, and then I used the finite element method (FEM) to calculate its acoustical behavior. I investigated several models to validate the geometric behavior. Then, I compared the simulation results with the literature [1], The comparison of the acoustic characteristics between different mouthpiece shapes shows that the selected parameters are suitable. In addition, I explained my settings in the software COMSOL v5.6 to achieve high-performance computing and reduce simulation time.

- by Gioele Greco
- •
- Acoustics, Music, Musical acoustics, Numerical Analysis

The aim of this technical report is to handle the Simulate to Innovate Award provided by ALTAIR, the objective of this award is to provide and recognize the use of CAE (Computer-Aided Engineering) simulation on Cairo university Team's Urban Car. This report and the analysis were represented during Shell Eco-Marathon 2021. As ALTAIR supported the teams participated in the marathon by providing not just free Altair software, but also some important virtual learning sessions to help and aid teams to improve their designs and performance. Simulation-driven design methods will be included with all the steps and results, and how could Altair software products help us to handle this improvement. Finite element analysis (FEA) is mandatory for design stages for either the chassis or the body. Altair Hypermesh with Opti structure solver ease the cycle of meshing and applying the basic analyses which applied to the car and applying a robust optimization to save some weight without decreasing the stiffness of the car with free sized optimization, with the aid of Hyperworks software for making some modifications on the CAD, like Snitching, suppress edges, or filling surfaces. Computational Fluid Dynamics (CFD) analysis is done using AcuSolve solver and visualized with the aid of AcuFieldView. [Simulate to Innovate Award Winner 2021]

An electronic medical record system is a digital application that enables hospitals to store patients' records electronically. The system allows an entire patient history to be viewed without the need to track down the previous medical record and assists in ensuring data is accurate, appropriate, and legible. Most hospitals in Nigeria still practice paper-based system of storing patients' records is prone to many errors ranging from the physical space to keep the large volume of patients' records; difficulty in reading some prescriptions to occurrences like termite attack, fire outbreak, flood and theft which can lead to loss of files and records. This paper developed an electronic medical record system for a t storing patients' records electronically and which makes it easy for medical practitioners to have access to patients' files at a glance, with ease and from anywhere they may be. The system can also allow patient appointments with any doctor of their choice and view some parts of their records. This was achieved by developing a computer application using javascript, HyperText Markup Language (HTML), and Cascading Style Sheets (CSS) for the front end, the Hypertext Preprocessor (PHP) for the backend, and MySQL for the database. The result of this research effort is an electronic medical record system which is a robust computer application that contains clinical data and provides support for clinical decision records with ease and from wherever they may be.

Qt GUI programming for visualization of Partial Differential Equations Approximations using Finite Element Methods.

Granular anchors (GAs) can resist pullout/uplift forces, compression forces and also provide ground improvement. Under pullout loading, a centrally located tendon transmits the applied surface load to the base of the granular column via a base plate attachment, which compresses the column causing significant dilation of the granular material to occur, thereby forming the anchor. This paper describes a program of field testing and numerical modelling of the pullout resistance of GA installations in overconsolidated clay for the undrained (short term) condition. Pertinent modes of failure are identified for different column length to diameter (L/D) ratios. The applied pullout load is resisted in shaft capacity for short GAs or in end-bulging of the granular column for long GAs. In other words, the failure mode is dependent on the column L/D ratio. A novel modification in which the conventional flat base-plate is replaced by a suction cup was shown to significantly improve the undrained ultimate pullout capacity of short GAs

- by Brendan C . O'Kelly and +1
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- Numerical Modeling, Geotechnical Engineering, Soil Mechanics, Numerical Modelling

Selective laser sintering (SLS) process has the potential to become one of the most useful additive manufacturing techniques in coming few years, because it has potential to easily produced complex shapes. Use of this process becomes more extensive, with the main advantages being a wide range of build materials available. So SLS can accommodate multiple applications throughout the manufacture process. It comes early with three main applications: conceptual models, functional prototypes, and pattern masters. Since then, they have been added with an extra module, which incorporates rapid tooling. Only disadvantage of SLS process that it is both time consuming and expensive when a new material comes into use. In this paper we will investigate the effect of part placement (X and Y direction) in the build on the dimensional accuracy and mechanical properties of part produced by this SLS process.

Accurate prediction of the formability in multistage forming process is very challenging due to the dynamic shift of limiting strain during the different stages depending on the tooling geometry and selection of the process parameters. Hence, in the present work, a mathematical framework is proposed for the estimation of stress based and polar effective plastic strain-forming limit diagram (r- and PEPS-FLD) using the Barlat-89 anisotropic plasticity theory in conjunction with three different hardening laws such as Hollomon, Swift, and modified Voce equation. Two-stage stretch forming setup had been designed and fabricated to first prestrain in an in-plane stretch forming setup, and, subsequently, limiting dome height (LDH) testing was carried out on the prestrained blanks in the second stage to evaluate the formability. The finite element (FE) analysis of these two-stage forming process was carried out in LS-DYNA for automotive grade dual-phase (DP) and interstitial-free (IF) steels, and the r-FLD and PEPS-FLD were used as damage model to predict failure. The predicted forming behaviors, such as LDH, thinning development, and the load progression, were validated with the experimental results. It was found that the LDH in the second stage decreased with increase in the prestrain amount, and both the r-FLD and PEPS-FLD could be able to predict the formability considering the deformation histories in the present multistage forming process with complex strain path.

Steel structural elements with variable cross-section, made of welded plates, are largely used in the construction industry for both beams and columns in accordance with the stress and stiffness demand in the structure. These types of elements are mainly used for the design of single storey frames with pitched roof rafters and pinned column base. Rafters and columns can be designed as tapered members made of steel welded plates, respecting the bending moment diagrams for gravitational load combination. This paper deals with experimental tests performed on tapered beam-columns elements, subjected to both bending moment and compressive axial force together with analytical investigation.

- by Dogariu Adrian and +1
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- Steel Structure, FEM Modelling and Numerical Simulation

This article will present the experimental activities and numerical analysis of an intervention technique efficiency. This technique applies a stainless or zinc coated steel wire mesh (SWM) bonded with epoxy resin to the masonry walls, on one or both sides. Important advantage of this technique may be related to its reversibility-wire mesh fixed with epoxy resin can be removed from the masonry wall by heating the resin layer. Steel wire mesh reinforced masonry walls have a complex behaviour and no analytic procedures for design are available; therefore, advanced numerical models confirmed by extended experimental tests are need. The experimental program is presented together with the finite element model adopted for retrofitted masonry specimens. The numerical model is calibrated according to the contact-less and full-field measurements. The experimental tests, carried-out within the framework of a European research project, have included tests on steel wires, on steel meshes, on 500 by 500 mm retrofitted masonry elements (diagonal tensile tests) and 1500 by 1500 mm masonry walls. The numerical calibration have been made using ABAQUS finite element software. The replacing of simple masonry with an equivalent material with improved behaviour, can be done following the experimental testing results. This kind of approach that considers the retrofitting steel wire mesh as an external reinforcing can really simplify the numerical effort.

Heat treatment was conducted to improve the ductility of locally manufactured mild steel rods (F e − 0.26 %C) obtained from Ferro-Fabrik, Tema, using tempering. Microstructural studies, hardness, impact and tensile tests were carried out on the mild steel rod samples before and after heat treatment. The samples were heated to 950 • C to austenitize them for 1 hour and rapidly quenched to room temperature in water to produce martensites. They were then re-heated to the tempering temperature of 500 • C for 1, 3 and 5 hours. Some of the martensitic samples were not tempered after quenching. The as-received samples (non-heat treated samples) had an average hardness value of 2290.5 ± 373.5 (Vickers Hardness 20) HV20. The martensitic samples had an average hardness value of 5477.0 ± 452.7 HV20. The samples tempered for 1 hour had an average hardness value of 2735.7 ± 577.6 HV20. The samples tempered for 3 hours had an average hardness value of 2470.2 ± 394.3 HV20 while the samples tempered for 5 hours had an average hardness value of 2198.6 ± 387.6 HV20. The as-received samples had an average impact energy value of 109.8 ± 6.8 J. The martensitic samples had an average impact energy value of 40.7 ± 5.0 J. The samples tempered for 1 hour had an average impact energy value of 114.3 ± 6.9 J. The samples tempered for 3 hours had an average impact value of 139.8 ± 2.3 J; while the samples tempered for 5 hours had an average impact value of 141.1 ± 3.9 J. From the tensile test the average percentage elongation of the as-received samples was 30.8 %. The martensitic samples had an average percentage elongation value of 17.5 %, whereas the samples tempered for 1, 3 and 5 hours had an average percentage elongation of 25 %, 30.0 % and 32.5 % respectively. The as-received and the martensitic samples had average percentage area reductions of 65.0 % and 42.5 % respectively. The samples tempered for 1, 3 and 5 hours at 500 • C had average percentage area reductions of 57.3 %, 64.0 % and 65.8 % respectively. The microstructure of the tempered samples revealed the formation of even distribution of ferrite and pearlite. The above results suggest that the ductility of locally manufactured mild steel rods may be improved by tempering.

Dual phase (DP) steel is of great interest for automotive part manufacturers due to its excellent combinations of strength and formability. Complex components involving three- dimensional stampings are usually fabricated through multistage sheet forming operations. The ability of a sheet metal to be deformed into a specific desired shape by distributing strain over arbitrary tool surface depends on complex interaction of material, process and design variables. The strain-based forming limit diagram (ε-FLD) is often used as a measure of formability in the press shop due to convenience of measuring the limiting strain. However, it was reported by previous researchers that the ε-FLD of sheet metal shifts after pre-strain due to the initial forming operations. Hence, this work proposes a mathematical framework for constructing σ-FLD of different pre-strained sheets incorporating Barlat-89 yield criterion with different hardening laws. The formability of biaxially pre-strained DP600 was evaluated experimentally in two stages. The forming behaviour of pre-strained material was predicted by finite element model using the σ-FLD, and the predicted results matched very closely with the experimental data. It was also observed that the σ-FLD was robust and
underwent insignificant changes due to the change in the pre-strain path.

The strength and ductility of a proposed intervention technique for retrofitting masonry walls using metallic sheathing were experimentally evaluated. Due to the masonry-connector-plate system complexity, a detailed ABAQUS FE-model of masonry shear walls reinforced by metal sheathing, was set up. The numerical model was experimentally calibrated so as to replicate the behaviour of the retrofitted elements allowing parametric analysis. By using the finite element model, a " numerical experiment " was performed in order to set up the behaviour of different retrofitted wall types. An equivalent material able to replicate the numerical behaviour of the retrofitted model was applied in the global analysis. The seismic safety based on the performance approach was evaluated for a study case building. A multi-decisional matrix was proposed for the validation of the retrofitting techniques which combines structural, technical and economic aspects.

Nowadays, transformers are made of conventional magnetic cores which are constructed of a single grainoriented or amorphous, magnetic steel. Even though, the transformer is the most efficient of electrical machines, with efficiencies typically above 90%, it is possible to improve transformer performance by using composite magnetic cores. Patents related to this simple and effective technique can be traced back to 1929. The specific technique can be applied to wound core distribution transformers. By using wound cores constructed with a combination of conventional and high permeability grain-oriented steel the total owing cost (TOC) of the transformer can be reduced effectively. This paper presents a brief review of patents on wound and composite magnetic cores and introduces a generalized technique for the determination of the optimum design variables of a new composite wound core design.

This paper proposes the manufacturing of distribution transformers using a novel type of magnetic core which is called composite wound core. A composite wound core is constructed of a combination of conventional and high magnetization grain-oriented steel. The main advantage of transformers assembled of composite wound cores over conventional transformers is the significant reduction of the manufacturing and operating cost. For the analysis of composite wound core transformers, a FE model considering anisotropy and high saturation conditions, and an advanced 3D hybrid FE-BE model have been developed.

A three-dimensional numerical model was developed to investigate the nonisothermal, non-Newtonian polymer flow through a cone cylindrical die used in the HDPE (high-density polyethylene) extrusion process. The numerical model was based on the computational fluid dynamics code COMSOL 3.4 the finite element method, and it was used to calculate pressure, flow, and temperature distributions in a cone cylindrical die used for industrial-scale extrusion of an HDPE rod. The model also accounted for viscous heating. In addition, pressure and temperature data were derived using an analytical solution. The numerical approach agrees fairly well with the experimental data recorded during the extrusion process of the material.

- by Giorgos Kouzilos
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- Polymer Engineering, Numerical Simulations, Modeling and Simulation, Simulation

In this study, Wire Arc Additive Manufacturing (WAAM) based Directed Energy Deposition (DED) process is used to build two parts, tube and wall from 2209 Duplex Stainless Steel. Duplex stainless steel is extremely effective against stress corrosion cracking due to existence of an equal portion of austenite and ferrite phases. The challenge is monitoring of the process parameters and cooling rate to promote ferrite phase formation. To this end, three-dimensional transient thermal models of the additive manufactured (AM) parts are presented and the simulated thermal cycles are verified with the experimental results. The correlation between the calculated cooling rates and the phases formation in the WAAM parts is studied and revealed. The results highlight that slow cooling rate of the built layers at elevated temperatures promote austenite formation significantly in a ferrite matrix. Furthermore, the experimental mechanical examinations will illustrate the quality of the WAAMmade parts and compare their mechanical properties with their wrought counterparts .

- by Farrokh Binesh and +1
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- Materials Science, Materials Characterisation, Scanning Electron Microscopy, Numerical Analysis

Numerical analysis of contact stresses at rotational elements of gerotor pumps with fixed position of shafts axis and with driving rotor acting as internal element, is presented in this paper. The basic characteristics and principles of functioning of this type of pumps are explained and review of researches in the area of numerical methods and developments and design optimizations of those pumps are presented. The basic assumptions, limitation and input values are defined in order to determine maximal stresses, numerical analysis of contact stresses, which are caused by transmitting of torque from internal to external gear. The obtained results of research contact stresses by numerical and analytical method are graphical presentations. The comparisons of results for better understanding of its deviations also were performed.

- by Applied Engineering Letters and +2
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- Engineering, Mechanical Engineering, Numerical Simulations, Numerical Modeling

Modelling and Simulations have been applied in various engineering disciplines since the 1990s, especially in the area of defence, being an essential tool in all phases of the cycle of acquisition and in all applications whose main objective are to reduce the time, resources, and risks associated with acquisition, to enable the integrated product and process development, and to improve the quality of the fielded product. One of the main purposes of this research is to demonstrate the importance of Systems Engineering (INCOSE) as part of the defence acquisition system and how this engineering discipline has incorporated the use of Modelling and Simulations into their acquisition-cycle phases and processes.

Notice No responsibility is assumed by the publisher for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions or ideas contained in the material herein. Because of rapid advances in the medical sciences, in particular, independent verification of diagnoses and drug dosages should be made.

This paper presents the analytical computation of the slot leakage inductance for permanent magnet (PM) machines with tooth-coil winding (TCW). Inductance equations are derived with detailed permeance determination for vertical or horizontal coil side arrangement in the slots, assuming a straight-line path for the flux leakage. Generalized expressions for the slot leakage inductance of the whole phase for different slots and poles combinations are proposed to be used during the dimensioning stage of a machine. Finite element (FE) simulations were carried out in a 6 slot and 4 pole machine to validate the analytical expressions, showing a good agreement between both methods.

- by Dimitrios Manolakos
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- Polymer Engineering, Heat Transfer, FEM, Heat and Mass Transfer

Calibration curves of a multi-component dynamometer is of essence in machining operations in a lathe machine as they serve to provide values of force and stress components for cutting tool development and optimization. In this study, finite element analysis has been used to obtain the deflection and stress response of a two component cutting tool lathe dynamometer, for turning operation, when the cutting tool is subjected to cutting and thrust forces from 98.1N to 686.7N (10 to 70kg-wts), at intervals of 98.1N(10kg-wt). By obtaining the governing equation, modeling the dynamometer assembly, defining boundary conditions, generating the assembly mesh, and simulating in Inventor Professional; horizontal and vertical components of deflection by the dynamometer were read off for three different loading scenarios. For these three loading scenarios, calibration plots by experiment compared with plots obtained from simulation by finite element analysis gave accuracies of 79%, 95%, 84% and 36%, 57%, 63% for vertical and horizontal deflections respectively. Also, plots of horizontal and vertical components of Von Mises stress against applied forces were obtained.