Mechanical APDL Research Articles

Simulations of Triple-GEM tracker's response for experiments at Jefferson Lab

ABSTRACTThis paper is about the Gas Electron Multiplier (GEM), a gas detector that will be installed on the new Super BigBite Spectrometer (SBS), under construction at Jefferson Laboratory in Newport News, VA, USA; the main interest of JLAB physics is the study of the fundamental interactions and constituents of hadronic matter and in particular the study of the electromagnetic Form Factors of the nucleons. The Italian group, JLAB12, is engaged in the construction, characterization and commissioning of two of the detectors that will be implemented in SBS: the GEM front tracker and the hadron calorimeter HCAL-J. A Gas Electron Multiplier is a gas detector useful to track the charged particles. It is composed of 2 layers of copper and a layer of Kapton, a dielectric material; all the layers together are inside a box with a mixture of gas: of Argon an of CO. In each GEM foil there are a lot of biconical holes, and it is placed between a drift plane and a readout plane; when a charge particle crosses the gas, it loses energy creating couple ion-electron. If we apply a potential difference, the pairs are accelerated by the electric field, and they have enough energy to create an avalanche. The gain that we can reach with a single GEM foil is 1000. In JLAB's configuration for SBS, a TripleGEMs system will be used; a TripleGEM is composed of 3 GEM foil placed in cascade. The advantages of this technology are: the layers structure, so the primary ionization, the multiplication and the charge collection regions are separated, the high gain about 100,000, the flexibility of geometry, the good spatial resolution about 70 µm, low costs and small streamer or charging up phenomena. To verify GEMs performances and to optimize the digitalization model, we started simulations changing some physical and geometric parameters. In order to run the GEM's simulations, we used two different software: ANSYS Mechanical APDL to create the detector geometry, assign the materials, define the meshes in shape and size and the electric field, and Garfield++, a toolkit for detailed Monte Carlo simulation of a gaseous detector, to evaluate the distribution of the charged particles on the readout plane when we change some parameters like the type of the primary particle, its energy and its incident slope. In particular, we built two different models: a triple GEM model and a cascade model; we are comparing the simulations results with the real test that we did in Juelich (Germany) with a beam of 2.8 GeV protons.

Dynamic analysis of an offshore jacket platform with a tuned mass damper under the seismic and ice loads

Herein, we present numerical simulation based model to study the use of a \'Tuned Mass Damper (TMD)\' - particularly spring mass systems - to control the displacements at the deck level under seismic and ice loads for an offshore jacket structure. Jacket is a fixed structure and seismic loads can cause it to vibrate in the horizontal directions. These motions can disintegrate the structure and lead to potential failures causing extensive damage including environmental hazards and risking the lives of workers on the jacket. Hence, it is important to control the motion of jacket because of earthquake and ice loads. We analyze an offshore jacket platform with a tuned mass damper under the earthquake and ice loads and explore different locations to place the TMD. Through, selected parametric variations a suitable location for the placement of TMD for the jacket structure is arrived and this implies the design applicability of the present research. The ANSYS*TM mechanical APDL software has been used for the numerical modeling and analysis of the jacket structure. The dynamic response is obtained under dynamic seismic and ice loadings, and the model is attached with a TMD. Parameters of the TMD are studied based on the \'Principle of Absorption (PoA)\' to reduce the displacement of the deck level in the jacket structure. Finally, in our results, the proper mass ratio and damping ratios are obtained for various earthquake and ice loads.

Finite Element Analysis of Direct Chill Casting using Concept of Element Birth and Death

A direct chill (DC) casting is a continuous casting process widely used in different industries. The aim of the work is to investigate thermal and mechanical stress formed during the direct chill casting process by a numerical method. A commercial software ANSYS mechanical APDL is used for the simulation. A moving mesh technique is employed for the development of ingot during the solidification process. An element birth and death concept is used to find out the deformation in ingot. The verification of the results is done with the results found in literature and found a good agreement. The developed model has admirable ability to predict the thermal and mechanical stress formed in direct chill casting process.

Formulation of a Method for Assessment of Fatigue Life, Formation and Propagation of Cracks

An engineering method for assessing fatigue life, taking into account the accumulation of damage and allows determining the trajectory of the fatigue crack. The calculation is performed by successive approximations based on the ANSYS Mechanical APDL software package in both linear and nonlinear installations. Stages of calculation of fatigue, cracking and fatigue failure of the structure alternate.

Software for deformable solid mechanics

Subject of Research. The paper presents a software building method for the tasks of deformable solid mechanics. This software should guarantee high accuracy and speed of calculations, as well as simple preparation of the initial data and data processing even for an inexperienced user. The software was developed using the open source GMSH mesh generator application programming interface (API) and the Eigen mathematical library. Method. The developed software consists of three modules: GMSH_API, InputFile, FEMSolver and a database. The GMSH_API module, which prepares the finite element model, was written using the GMSH mesh generator API. The InputFile module describes methods for interacting with a previously created database, that provides quick and easy preparation of the input file needed to start the calculation. Numerical calculation by the finite element method is implemented in the FEMSolver module. The Eigen mathematical library was actively used for its implementation, and it can build sparse matrices that do not store zero elements in memory. This possibility obviates the need for additional transformations of the global stiffness matrix used in the finite element method. Main Results. The Kirsch task was solved as an example in a plane-stressed setting: a distributed tensile load was applied to the upper edge of a steel plate, with a round hole in the center, the lower edge of the plate was rigidly fixed. After calculating and obtaining the von Mises stress distribution field in the plate, we observe an error of 1.72% relative to the analytical solution. Such error value is considered low, therefore, the developed software not only facilitates the preparation of data for calculation, but also guarantees high accuracy of the obtained results. Practical Relevance. Commercial software for solving the problems of deformable solid mechanics, such as ANSYS Mechanical APDL, Abaqus, etc., is very expensive. Free software is primarily focused on researchers and, as a rule, is difficult for learning by an ordinary user-engineer, and the compromise version of the PDE Toolbox for MATHLAB is applicable only for tasks in a two-dimensional area and only supports a linear triangular finite element. However, the application of GMSH API and the Eigen library provides for creation of an easy-to-use but powerful tool for solving the problems of deformable solid mechanics.

DEVELOPMENT OF AN INTEGRATED METHOD OF CALCULATION OF THE STRESSED-DEFORMED STATE OF THE COMPOSITION SHELL IN THE PROCESS OF MANUFACTURE

The paper discusses the key stages of developing an integrated methodology for predicting the stress-strain state of a sand-polymer mandrel-plastic shell system during heat treatment with the adaptation of experimentally determined viscoelastic characteristics of components in the CAE ANSYS Mechanical APDL package. The first stage solves the problem of determining the effective viscoelastic characteristics for the shell. Viscoelastic characteristics are determined on the basis of the developed complex experimental calculation method based on the solution of boundary quasistatic problems of thermomechanics on a representative volume at two scale levels. The results obtained in this work, based on experimental data and developed numerical methods for determining the thermo-viscoelastic characteristics of composites, make it possible to estimate the contribution of stress relaxation in the mandrel and the shell to the evolution of the stress-strain state in the process of manufacturing the shell. Also, the developed technique makes it possible to predict the appearance of technological defects and determine the stages of heat treatment at which these defects occur.

Modelling of Nanoindentation of TiAlN and TiN Thin Film Coatings for Automotive Bearing

Bearings are critical components for the transmission of motion in machines. Automotive components, especially bearings, will wear out over a certain period of time because they are constantly subjected to high levels of stress and friction. Studies have proven that coatings can extend the lifespan of bearings. Hence, it is necessary to conduct studies on coatings for bearings, particularly the mechanical and wear properties of the coating material. This detailed study focused on the mechanical properties of single-coatings of TiN and TiAIN using the finite element method (FEM). The mechanical properties that can be obtained from nano-indentation experiments are confined to just the Young’s modulus and hardness. Therefore, nanoindentation simulations were conducted together with the finite element method to obtain more comprehensive mechanical properties such as the yield strength and Poisson’s ratio. In addition, various coating materials could be examined by means of these nanoindentation simulations, as well the effects of those parameters that could not be controlled experimentally, such as the geometry of the indenter and the bonding between the coating and the substrate. The simulations were carried out using the ANSYS Mechanical APDL software. The mechanical properties such as the Young’s modulus, yield strength, Poisson’s ratio and tangent modulus were 370 GPa, 19 GPa, 0.21 and 10 GPa, respectively for the TiAlN coating and 460 GPa, 14 GPa, 0.25 and 8 GPa, respectively for the TiN coating. The difference between the mechanical properties obtained from the simulations and experiments was less than 5 %.

Effect of HUD-HUD Wind Intensity on the Structural Behaviour of 220kv Transmission Line Tower at Visakhapatnam

The transmission line towers are one of the important transmission line structures in the distribution of power from the source to the various places. Transmission line towers carry heavy electrical transmission conductors at a sufficient and safe height from ground. In addition to their self-weight they have to withstand all forces of nature like strong wind and earthquake. Therefore transmission line towers should be designed considering both structural and electrical requirements for a safe and economical design. In this paper, an attempt has been made to analyse the behaviour of Transmission line tower under the influence of natural disaster hit Visakhapatnam (District) in Andhra Pradesh (State), India recently in the month of November, 2014. The 220kV tower is modeled and analysed using STADD Pro V-8i and Ansys Mechanical APDL for Maximum loading combinations considering HUD-HUD wind intensity of 275 km/hr (76m/s) and the results obtained are compared with the results obtained for regular wind intensity of 180km/hr(50m/s). Also, the velocity profiles are drawn for both the wind speeds.

ANALYSIS OF DEFORMED CONDITION OF SHUTTERS LOCATED ON ROLLER-PROOFERS

When assembling the shells of cylindrical vessels and apparatus, there are increased requirements for deviations of geometrical parameters and for the accuracy of installation of internal devices. The requirements for deviations of the shape and size of the shells of cylindrical vessels and apparatus, the maximum allowable values of the displacement of the edges during welding of shells were considered. The study of deformations will allow to understand their structure, which, in turn, will increase the accuracy in the manufacture of vessel shells and apparatus. Most of the cylindrical shells are assembled in a horizontal position when the shells lie on the roller supports. The article presents an analysis of the deformations arising under the action of gravity in the shells located on the roller supports. A simulation of the deformations occurring in the shells located on the roller bearings due to the action of gravity was carried out using the finite element method. The simulation was carried out in the ANSYS software package, in the Mechanical APDL module. The dependences of the magnitude of the maximum strain as a function of the angle of the rollers were studied. The dependence of the deviation of the conventional axis of the apparatus on the real from the distance between the pairs of rollers was also investigated. Methods for controlling the geometric parameters of the shells, such as a mechanical profilograph and an automatic system for controlling geometric parameters using modern laser technologies, were considered. The results of the study showed that gravity did not significantly affect the deformation of the shells. The studies did not take into account the residual welding stresses, stresses and strains that occur during the assembly of the shells. The obtained value of the optimal angle of location of the rollers is 140o. It is necessary to establish the maximum angle of location of the roller, if they can not be located at an angle of 70o. The deviation of the real axis of the apparatus from the conditional is within 0.5 mm, which does not significantly affect the accuracy of production. The resulting ovality of the end and central sections under the influence of gravity on the body does not exceed 0.1 %, which is within the limits of acceptable values.

Aerodynamic and structural analysis of bio-mimetic corrugated wing

This work includes the aerodynamic and static structural analysis of newly designed bio-mimetic corrugated aerofoil inspired from dragonfly forewing. Dragonfly corrugated aerofoil structure used in this research comprised of basal wing section located near the radius of the forewing. These corrugations define the stressed skin structure composed of griderlike veins structure and thin cuticle membrane which provides sophisticated mechanical advantage for resisting longitudinal bending while facilitating wing camber and torsion. Dragonflies are known for their impressive flight performance .They carry aerodynamic and inertial loads. A computational analysis is done on a newly designed dragonfly corrugated aerofoil at Reynolds number of 37660, where flow is assumed to be laminar, steady, incompressible and two dimensional. The research comprises of the aerodynamic flow analysis of 2-D dragonfly corrugated aerofoil and static structural analysis using Ansys Fluent and Ansys Mechanical APDL. It is found that the design criteria being used and simulation carried out on corrugated aerofoil is giving much better results compared to earlier studies. The structural analysis also shows that it can resist maximum pressure loads and provides high rigidity to the span of the wing. These finding enhances the knowledge of insect inspired corrugated wing structure and facilitate the application for improved design of artificial wings for MAVs and UAVs

Numerical model of fracture growth in hydraulic re-fracturing

Simulation of fracture propagation with FEM method generates the need of re-meshing to provide more accurate results. This raises a question of determining the direction and criterion of mesh modification. In the case of general-purpose CAE-packages, we deal with a stationary mesh, and the fracture path is usually represented as a chain of elements with degraded properties. The algorithm proposed in this paper is based on the ANSYS Mechanical APDL language for stepwise geometry reconstruction and mesh modification in accordance with the current configuration of a growing fracture and provides a more accurate description of its shape. The fracture propagation process is divided into stages. Each subsequent stage differs from the previous one by the fracture shape modified due to the crack length increment in the calculated direction. To check the adequacy of the model, an experiment on fracture propagation in glass specimens with an initial notching under uniaxial compression was performed. The laboratory experiments were carried out to determine the fracture toughness of rocks. The developed numerical model has been used to solve the problem of re-fracturing for different stress anisotropy in the oil-bearing rock formation.

Modeling and Experimental Study of Al-Cu Alloy Sand Casting for Circuit Breaker

Aluminum is a light metal with good electrical conductivity and widely applied for electrical devices. One of its application is the circuit breaker component. The 2xxx series of aluminum alloy has a copper alloying element which increases its mechanical properties and improves quality of electrical conductivity. This research aims to obtain the best gating system design of the circuit breaker mold by ANSYS modeling. This research also is subject to measure the influence of Cu alloying to the rate of electrical conductivity, strength, and hardness in aluminum alloys for circuit breaker application by experimental working. Aluminum is alloyed with variations of 1; 2; 3; 4; and 5% copper addition. Modeling of thermal analysis and structural analysis was calculated by ANSYS Mechanical APDL with a finite element method to find the best design for the sand casting experiments. Chemical composition, metallography, brinnel hardness, tensile, XRD, and electrical conductivity tests were conducted in this study. The highest strength is 59.50 MPa was acquired on Al - 3% Cu while the lowest strength is 37.43 MPa was on Al - 1% Cu alloy. The peak of hardness 48.70 HBN could be drawn at Al - 4% Cu. In the other hand, the dip of it was Al 1% Cu of 25.5 HBN. The last variable, conductivity, has the highest amount as of Al-5C, alloys with a value of 12.88 S / M, which is found on Al-1Cu with a value of 9.30 S/m.

Modeling and Buckling Analysis of Rectangular Plates in ANSYS

With plate-buckling problem still being an active area of research in the field of mechanics of materials, researchers need to validate the proposed solutions and theories, using robust analysis tools such like ANSYS, which is a robust finite element analysis tool. This article investigates modeling and buckling analysis of rectangular plates in ANSYS mechanical APDL through a series of comparative studies conducted on various models and options. Shell and solid models of homogeneous and functionally graded plate (FGP) using various elements are investigated. Expressing boundary conditions on both shell and solid models of plate for buckling analysis is discussed. Procedures of buckling analysis in ANSYS are presented and effects of meshing, boundary conditions and element options are examined though comparative studies. Results obtained from ANSYS are compared to various analytical solutions.

About definition of the elasticity module of single-walled carbon nanotubes by methods of structural mechanics

The purpose of article is working off and check of numerical techniques of definition of elasticity module of single-walled carbon nanotubes with use of a method of final elements, and also ties between parameters of molecular and structural mechanics. Researches were conducted for nanotubes of various types of spatial and frame models, namely armchaіr type, zigzag type and chіral type. Program codes with use of freely open software of Gmsh are developed for design of models of nanotubes of these types. Formulations of linear and nonlinear ratios for determination of parameters of structural mechanics on basis of energy potentials and power coefficients of molecular mechanics are considered. The formulation of a nonlinear problem received a certain specification regarding definition of ratios the generalized deformation – generalized tension. The numerical models for research of elasticity module of nanotubes of various dimension-types (chіrality and diameter) representing macroes in APDL ANSYS Mechanical APDL programming language are developed. Results of comparison of received results showed satisfactory coordination with theoretical and experimental data: divergence with known theoretical estimates makes 0.08–5.1 %. The offered verified numerical techniques for definition of elasticity module of nanotubes are planned to be used further for development of new polymeric nanocomposites.

The Piezoelectric Phenomenon in Energy Harvesting Scenarios: A Theoretical Study of Viable Applications in Unbalanced Rotor Systems

The present paper deals with the promising energy harvesting applications of a composite piezoelectric metal support that is properly designed for the rotor of a mechanical system. The aim is to determine whether the vibrational power coming from the static residual imbalance, which is generally considered to be an undesired and useless side-effect of the rotation, can be converted into electric power and then stored to be used in other applications. The analysis, starting from the Jeffcott rotor model and the piezoelectric constitutive equations, has been carried out by developing an approximated linear model of a piezoelectric support, in order to theoretically evaluate the performance and the feasibility of the proposed system. The accuracy of the exploited analytical model has been validated for both static and dynamic operations by 3D Ansys® Mechanical APDL. Finally, a MatLab®/Simulink® model has been built to simulate the electric behavior of the piezoelectric material, and to estimate the power that it is possible to extract via an alternative/direct current converter (AC/DC converter). The numerical results achieved confirm the effectiveness of the proposed energy-harvesting system.

Quantifying numerically forecast size effects in the free vibration of heterogeneous beams

This paper reports on the influence that a periodic microstructure has on the unconstrained flexural vibration of geometrically similar but differently sized heterogeneous beam samples. A numerical investigation was conducted by finite element analysis (FEA) incorporating the detailed heterogeneity to identify and quantify any effect of beam size on the transverse modal frequencies when the microstructural scale is comparable to the overall size. Finite element models of the macroscopic beam samples were created by firstly specifying microstructural scale unit cells containing a single void or inclusion using ANSYS Mechanical APDL and then repeatedly regenerating these as required. Four beam sizes consisting of one, two, three or four layers of unit cells were created while the length to depth aspect ratio was kept constant for all sizes. Void or inclusion volume fraction was also altered while keeping the homogenised mass and stiffness properties of each beam fixed. The influence of the beam boundary texture on the results was also investigated. The ANSYS results were compared to the analytical solution for a conventional Timoshenko beam and a nonlocal Timoshenko beam. Using the nonlocal Timoshenko analysis, the Eringen small length scale coefficients were estimated but found to be size dependent. Numerical predictions obtained from a novel control volume based finite element (CVFEM) procedure incorporating micropolar constitutive behaviour were therefore matched to the ANSYS results and thereby used to identify the two additional constitutive parameters featuring in planar micropolar elasticity theory, namely the characteristic length in bending and coupling number.

Finite Element Analysis of Fiber Reinforced Hybrid Composites

Abstract Composite materials are very beneficial in a comparison to other engineering material. In terms of usage, they are lighter in weight and having strength which is sometimes greater than conventional material in use. It also resists many types of loads under working conditions that may also include the environmental impact. Composite materials made from natural materials are also biodegradable in nature and that's why they are environment-friendly. They can be easily designed and fabricated in different shapes as per requirement. In this paper, composite specimens were designed by using five different types of fibers. These different fiber are natural fibers (banana, Cactus, and jute) and synthetic fibers (glass and carbon). Thus, a finite element study of these specimens was conducted by blending these fibers with each other. The arrangements were chosen using permutation and combination. After designing the specimen, many types of FEM analysis were done on ‘ANSYS' Mechanical APDL by applying a point load on samples. Through the current study, hybrid composites were analysed under the same loading conditions and their deflection results were compared. It could step to sustainable development making a hybrid composite. And a good quality composite could be designed for the manufacturing a great strength material.

Stress Analysis of Buried Pipeline Installed by Horizontal Directional Drilling Using ANSYS Finite Element Software

In designing a horizontal directional drilling (HDD) pipeline project, designers face the challenge of determining the regions of maximum and minimum stresses on pipelines, ensuring the stability of the bore-hole from collapse and minimizing the stresses induced on the pipeline due to the bore-profile. This study analyses the stress induced on an HDD pipeline system using the ANSYS Version 18, mechanical APDL finite element (FE) software. The pipeline used as the case study was a gas transmission pipeline installed in south-west Nigeria. A macro-file for ANSYS Version 18, mechanical APDL used to model the pipeline was developed. The results showed that the maximum and minimum stresses induced on the HDD pipeline were at the top and bottom of the pipe, respectively; while the stresses on the sides were uniform (≈888 kg/cm2) all through the pipeline, irrespective of element number. The maximum stress occurred at the curvature point with the highest entry angle (10°), resulting in a maximum deflection at this point. The model stress validation performed by comparing results with theoretical solutions, both with respect to radius of curvature and internal pressure, showed percentage difference (errors) less than 10%. The cross sectional area validation showed a percentage difference of 0.059%.

Flexural‐Torsional Vibration of Thin‐Walled Beams Subjected to Combined Initial Axial Load and End Bending Moment: Application to the Design of Saw Tooth Blades

The present paper analyzes the vibration issue of thin‐walled beams under combined initial axial load and end moment in two cases with different boundary conditions, specifically the simply supported‐end and the laterally fixed‐end boundary conditions. The analytical expressions for the first natural frequencies of thin‐walled beams were derived by two methods that are a method based on the existence of the roots theorem of differential equation systems and the Rayleigh method. In particular, the stability boundary of a beam can be determined directly from its first natural frequency expression. The analytical results are in good agreement with those from the finite element analysis software ANSYS Mechanical APDL. The research results obtained here are useful for those creating tooth blade designs of innovative frame saw machines.

Моделирование гибких тканых композитов в системе ANSYS Mechanical APDL

В настоящей работе предложен вариант импорта в систему ANSYS Mechanical APDL модели поведения гибких тканых композиционных материалов с армирующей тканью полотняного переплетения при статическом растяжении вдоль нитей армирования. Импорт осуществлен при помощи использования, разработанного авторами и представленного в текущей работе модуля интеграции, основанного на использовании аналитической модели деформирования исследуемого материала, представленной в опубликованных ранее статьях и учитывающей изменения геометрической структуры, происходящие в армирующем слое материала в процессе деформирования, образование необратимых деформаций и взаимодействие накрест лежащих нитей армирующей ткани. Во введении кратко описаны основные вводимые характеристики полотняного переплетения армирующей ткани и аналитической модели, импортируемой в ANSYS. Аналитическая модель основана на описании процессов деформирования элементарной периодической ячейки исследуемого класса материалов. Входными параметрами модуля являются механические характеристики материалов, входящих в состав композита (связующее и материал нитей армирования), геометрические характеристики переплетения армирующей ткани. Алгоритм импорта модели основан на вычислении и передачи в ANSYS расчетных точек диаграммы деформирования материала при одноосном растяжения вдоль направления армирования и использовании вложенных в систему ANSYS пользовательской моделей материала Multilinear Kinematich Hardening. Аналитическая модель, импортируемая при помощи представленного модуля, позволяет моделировать композиционный материал с армирующей тканью без детального описания геометрии переплетения нитей при моделировании материала в целом. Выполнена верификация импортированной модели. Для верификации были проведены натурные экспериментальные исследования и численное моделирование растяжения образцов из гибких тканых композитов. В экспериментах принимали участие образцы трех марок: VP4126, VP6131 и VP6545. Погрешность импортированной в ANSYS модели составила менее 10 % относительно экспериментальных исследований для всех марок материала. Анализ полученных результатов показал хорошее качественное и количественное согласование расчетов в системе ANSYS с применением импортированной модели и натурных испытаний до величин предельных деформаций, соответствующих разрушению образцов материала для всех исследуемых марок гибких тканых композитов, что позволяет сделать вывод о возможности применения предложенного модуля при моделировании процессов деформирования гибких тканых композитов и конструкций, созданных из таких материалов при статическом одноосном растяжении вдоль нитей армирования.