ANSYS Mechanical APDL Research Articles

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.

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 %.

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.

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.

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.

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.

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.

Structural Optimization Coupled with Materials Selection for Stiffness Improvement

Abstract An application of a Finite Element Model updating is presented in this paper. Two Finite Element models were considered: a reinforced plate and a thin-walled beam. The two parts were numerically calculated in ANSYS Mechanical APDL and MATLAB programs. ANSYS performs Finite Element calculations, and a MATLAB programming code was used to control the optimization procedure. Geometric variables were chosen, to evaluate the value of the defined objective function. The material was picked using available selection charts, to find the most adequate one for the study. It has been concluded that the transveral displacement of the models modified by the optimization process decreased sharply in relation to the original state.

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.

Bovine bone natural frequencies evaluation by using transfer matrix method based upon DICOM images

This study presents the use of the transfer matrix method to calculate the natural frequencies for bovine bone. The bovine bone was considered as continues system. This continues system was transferred to discrete system by discretizing it using the Digital Imaging and Communications in Medicine (DICOM) images obtained from CT-Scan test. Those images were used to evaluate the geometrical properties of the bone segments. Geometrical properties variation along the bone length were evaluated by using image-processing technique (Binary Image). Each slice was considered as beam and the total number of beam segments is equal to the number of DICOM images. The bone was divided into 226 segments (1.25 mm slice thickness). Euler Bernoulli equation of motion was used to formulate the transfer matrix. Finite elements method based on ANSYS mechanical APDL version 14.5 was used to calculate the natural frequency. This method was used to check the discrepancy of the results obtained from the transfer matrix method. This method was done by building the three dimensional modal based upon the DICOME images and solving the modal analysis by using ANSYS software. The deviation in the results obtained from the two methods was less than 15%. The simplicity and efficiency of transfer matrix method recommends further improvement by using the gray images instead of binary images to evaluate bone geometrical, physical, and mechanical properties based upon the grayscale value of each pixel for both cortical and compact bone.

Towards a unified formulation for the ultimate strength assessment of uncorroded and pitted platings under uniaxial compression

A benchmark study, devoted to systematically investigate the ultimate strength of simply supported platings under uniaxial compression, is performed to develop unified design formulas, accounting for geometrical imperfections, welding residual stresses and pitting corrosion wastage. Particularly, two boundary conditions for the in-plane motion of longitudinal edges, namely free and fully restrained, are considered as they significantly affect the plating behaviour in the post-buckling regime. Several practical design equations for uncorroded platings are derived to account for different levels of initial deflections and residual stresses, based on a wide and systematic series of elasto-plastic large deflection analyses performed by Ansys Mechanical APDL. Subsequently, proposed formulas are extended to platings affected by pitting corrosion wastage, on the basis of a new series of FE analysis, where the pitting intensity and corrosion degrees are systematically varied based on random distribution of the corrosion wastage on the plate panel. Finally, the goodness of proposed formulas is checked against current Rule equations, as well as several experimental collapse tests and FE results available in literature.

Investigation on the mechanical properties and mechanical stabilities of pipewall hydrate deposition by modelling and numerical simulation

The mechanical properties and mechanical stabilities of pipewall hydrate deposition are of great importance to the prevention and removal of pipeline hydrate plugging. In this paper, the mechanical properties and mechanical stabilities of pipewall hydrate deposition are quantitatively investigated by modelling and numerical simulation. First, a structural model for pipewall hydrate deposition is established based on particle packing theory. Using this structural model, the main mechanical parameters of pipewall hydrate deposition can be calculated. Then, numerical simulations using finite element method and ANSYS Mechanical APDL 14.5 are conducted based on the calculated mechanical parameters. Through the simulations, the structure deformation, internal stress distribution and failure of pipewall hydrate deposition when it is under the action of external forces are studied and the influences of flow rate, deposition thickness and deposition length are investigated. The results of this paper can provide guidance for pipeline flow assurance.

Finite element analysis of experimentally tested RC and PC beams using the cracked membrane model

Investigating/modelling numerically the static behaviour of RC and PC beams with composite cross-sections, taking into account their materials-dependent nonlinearities, is still a challenge, but today’s numerical tools are very effective in helping both designers and researchers to reduce the computer time and to take care of models complexity. In this paper, nonlinear finite element (NLFE) analysis is used to perform numerical analysis of experimentally tested directly and indirectly supported full-scale plates and beams. The constitutive law for reinforced concrete used in the NLFE analysis is based on the cracked membrane model and was implemented as a Usermat in ANSYS Mechanical APDL. The algorithm for the constitutive law and some important aspects of the modelling process are presented. As part of the NLFE analysis of the test specimens (one plate, one beam subjected to torsion, one directly supported reinforced concrete beam, one directly supported prestressed concrete beam, and one indirectly supported prestressed concrete beam), the calculated load–deformation curves, crack patterns, stress in the reinforcing steel at the cracks, and principal concrete compressive stresses are compared with the corresponding measured values.

Analytical solution and numerical validation of piezoelectric energy harvester patch for various thin multilayer composite plates

The study of vibrational energy harvesting using piezoelectric patch integrated on isotropic beam-like or plate-like thin structures has received significant attention over the past decade. Multilayer orthotropic composite plates are widely used in aerospace, automotive and marine applications, where they can be considered as host structures for vibration-based energy harvesting. In this paper, an exact analytical solution and numerical validation of a piezoelectric energy harvester structurally integrated to a thin multilayer orthotropic plate are presented. Electroelastic model of the thin multilayer composite plate with the piezoelectric patch harvester is developed based on a distributed parameter modeling approach with classical laminate plate theory assumptions for all-four-edge-clamped (CCCC) boundary condition. Closed-form steady-state expressions for coupled electrical outputs and structural vibration response are derived under harmonic transverse force excitation in the presence of a resistive load. Analytical electroelastic FRFs related to the voltage output as well as vibration response to force input are derived and generalized for different boundary conditions of host plate. The results of numerical and analytical models from multiple vibration modes are compared first for validating the analytical model with a case study employing a thin PZT-5A piezoceramic patch attached on the surface of a multilayer orthotropic composite CCCC plate. For this purpose, finite-element analysis is carried out by using ANSYS mechanical APDL software. Then, it is important to specify parameters in energy harvesting model, so positioning of piezoceramic patch harvester and excitation point force on the voltage output FRFs is discussed through an analysis of dynamic strain distribution on the overall plate surface. In addition, the effects of various composite laminate plates with different stacking sequences as host structures on generated power are discussed in details as well.

Experimental and numerical verification of transient spatial temperature distribution in thick-walled pressure components

The aim of this work is to present a method to determine the transient-state spatial temperature distribution in a cylindrical component. The presented method involves solving the inverse heat conduction problem based on the Finite volume method (FVM). This approach enables determination of transient-state temperature fields with boundary conditions known on one surface of the component only. The proposed method is verified using the laboratory installation located at the Cracow University of Technology. The main components of the laboratory stand are, among others, a steam outlet header and a steam boiler. During the experiment, the steam header is heated up abruptly from the inside by contact with dry saturated steam. The spatial transient-state temperature distribution within the steam outlet header is determined using the proposed method, which is based on temperature measurements made by 19 thermocouples located on the outer surface of the component. The temperature histories in three selected nodes are compared with the measurement results obtained from thermocouples located inside the component wall. The exact location of the thermocouples corresponds to the nodal position at selected control volumes. Moreover, the Ansys Mechanical APDL software is used to verify calculations and experimental data. A transient- state simulation is performed. The temperature histories at the inner and outer surfaces are set as the model boundary conditions. In order to enable verification of the temperature measurements, the component discrete model includes nodes at appropriate locations. An error analysis is performed between calculated and measured temperature values. The results obtained from the numerical and experimental validation demonstrate fully satisfactory agreement. Additionally, a stress analysis of the outlet header is performed in the Ansys software based on the transient-state temperature distribution within the steam outlet header. The method proposed in this paper is a convenient and accurate tool for monitoring working conditions of the power boiler thick-walled components.