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WSEAS Transactions on Applied and Theoretical Mechanics


Print ISSN: 1991-8747
E-ISSN: 2224-3429

Volume 11, 2016

Notice: As of 2014 and for the forthcoming years, the publication frequency/periodicity of WSEAS Journals is adapted to the 'continuously updated' model. What this means is that instead of being separated into issues, new papers will be added on a continuous basis, allowing a more regular flow and shorter publication times. The papers will appear in reverse order, therefore the most recent one will be on top.


Volume 11, 2016


Title of the Paper: Fuzzy Analysis of Serviceability Limit State of Slender Beams

Authors: Jan Valeš

Abstract: The maximum permissible deflection values in design standards are determined subjectively and can thus be considered as fuzzy numbers. Using the finite element method, it has been found that the lateral deflection of a slender beam under major axis bending can be relatively high. Nonlinear load-deflection analysis was applied for the compilation of the presented numerical studies. The serviceability limit state of beams with initial imperfections was studied. The limit moment, which yields the deflection that is equal to the maximum permissible value, was defined. Fuzzy analysis of the limit moment was evaluated using the general extension principle. Slendernesses of members for which the attainment of the maximum permissible value of deflection is the deciding limit state for design were determined.

Keywords: Fuzzy logic, resistance, imperfections, stability, serviceability, limit state, beam, bending

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #31, pp. 253-258


Title of the Paper: Using the Transformation Matrices not Only to Derive the Motion Equations

Authors: Jiri Zatopek

Abstract: This article introduces different ways of transformation matrices use. The first utilization is to determine the motion equations of the complex mechanical structure. Analysed model is designed in 3D CAD system SolidWorks. It consists of seven main physical objects. The corresponding inertia/pseudo-inertia matrix is derived for each of them with the aid of transformation matrices. These matrices are further used to derive the motion equations. The ball position scanning by camera system provides another possibility of the transformation matrix use; the camera local coordinate system is different against the plate local coordinate system and it is necessary to recalculate the real ball position. The final mentioned use of transformation matrices is in the determination of ball falling direction - it is valid only in case of its zero initial velocity.

Keywords: Motion Control, Transformation Matrix, Motion Equations, Gradient, Simulation, Matlab/Simulink

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #30, pp. 245-252


Title of the Paper: The Use of “Dog-Bone” for the Seismic Improvement of Steel MRFs

Authors: Rosario Montuori

Abstract: This work is devoted to the strengthening of steel moment resisting frame designed in order to bear vertical loads only. In particular, the idea is based on the attainment of improvement of seismic performance by simply trimming the flanges of the beam ends. This strategy can be applied by considering both the results of the theory of plastic mechanism control and the rules assuring the yielding of reduced beam sections (RBS) when seismic loads are applied to the structure. It is important to underline that the results of such strategy is not always effective. In fact, there are several condition that are to be satisfied in order to obtain an actual seismic improvement. Notwithstanding, when these conditions are satisfied, the cost of intervention can be considered as negligible. For this reason this strategy can be very interesting and the rules applied in this work can clarify which is the effect of RBS taking into account all the parameters playing a role in the final design:, i.e. existing column sections, resistance and ductility of existing connections, vertical loads acting in seismic load combination, amount of the reduction of beam section and its distance from the connection. By means of a worked example the effectiveness of the proposed procedure is shown.

Keywords: collapse mechanism, existing structure, reduced beam section, soft storey

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #29, pp. 229-244


Title of the Paper: Detailed Optimum Design of Reinforced Concrete Frame Structures

Authors: Sinan Melih Nigdeli, Gebrail Bekdaş

Abstract: This paper presents an optimum design approach for reinforced concrete (RC) frame structures which are excited by static and dynamic forces. In this approach, dimensions and reinforcements of all structural members are individually optimized without grouping them for optimum design. During optimization, the design rules given in ACI-318 (Building code requirements for reinforced concrete structures) are considered. Detailed seismic analyses are done by conducting time history analyses. The aim of the optimization is to find the most economical design of the frame structure. Additionally, the weight of the structure is indirectly reduced because of the consideration of dynamic analyses. A modified Harmony Search (HS) algorithm with additional random search iterations is developed for the optimization. The proposed method was demonstrated with a symmetric structure. The results show that the approach is feasible to find optimum designs of different structural members of RC frames.

Keywords: Optimization, Metaheuristic methods, Reinforced Concrete Structure, Time history analyses, Frame Structures, Harmony Search

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #28, pp. 220-228


Title of the Paper: Foldcore Structures and their Numerical Homogenisation

Authors: Holger Massow, Wilfried Becker

Abstract: The aim of this contribution is to give an overview of the possible applications and mechanical properties of folded sandwich cores. As the name already recognizes the structure is manufactured by folding from a flat semi-finished product. Folded cores possess some properties that make them particularly interesting for the aviation industry. To determine the mechanical properties a numerical homogenisation method has been applied. For a selected type of folded core the properties are exemplarily determined. The procedure is applicable to other types of sandwich cores as well. Also the mechanical properties are similar for other kinds of folded sandwich cores.

Keywords: Sandwich, folded core, homogenisation, effective properties, stiffness tensor, auxetic material

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #27, pp. 212-219


Title of the Paper: An Artificial Neural Network Based Approach for Impact Detection on Composite Panel for Aerospace Application

Authors: M. Viscardi, P. Napolitano

Abstract: Fleet maintenance and safety aspects represent a strategic aspect in the managing of the modern aircraft fleets. The demand for efficient techniques of system and structure’s monitoring represent so a key aspect in the design of new generation aircraft. This is even more significant for composite structures that can be highly susceptible to delamination of the ply, which is often very difficult to detect externally and can lead to a dramatic reduction of design strength and service life, as a consequence of impact damage. The purpose of the work is the presentation of an innovative application within the Non Destructive Testing field based upon vibration measurements. The aim of the research has been the development of a Non Destructive Test (NDT) which meets most of the mandatory requirements for effective health monitoring systems while, at the same time, reducing as much as possible the complexity of the data analysis algorithm and the experimental acquisition instrumentation.

Keywords: SHM, composite materials, piezoelectric materials, impact detection, NDT

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #26, pp. 203-211


Title of the Paper: A New Theoretical Approach on Teenage Cyclist-Vehicle Crash

Authors: Filippo Carollo, Vincenzo Naso, Gabriele Virzi’ Mariotti, Luigi Cannizzaro

Abstract: Data obtained in teenage cyclist impact against three vehicles (sedan, SUV and Pick Up), tested in previous works, are analyzed to verify the theoretical results by the coupling of momentum conservation principle and energy conservation principle. The speed of vehicle and thorax are compared with theoretical ones, obtaining an excellent agreement. Following the results found in the literature, particular emphasis is done on teenager cyclist thorax and head speeds, indicating that the cyclist speed can be theoretically until 1,41 times the impact speed, while greater values, until 2, are obtained in the simulations. A small slowing of the vehicle is found theoretically and in the simulations, due to kinetic energy transfer. A small component of the vehicle speed exists in the orthogonal plane to the motion, due, for example, to the compression of the rider body on the bonnet. A parameter is determined using all the data in term of thorax speed, in all the impact speeds and in all the relative positions; its value does not appear depending on the vehicle mass. It allows the subsequent determination of the best values of three geometric actual parameters identified in front of the vehicle: bumper height, bonnet height and bonnet inclination angle, by interpolation with a second order curve, by making the conclusion that the frontal part of the vehicle may be designed in order to reduce the injury.

Keywords: teenage bicyclist, vehicle impact, front vehicle shape, mass influence, theory of impact

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #25, pp. 192-202


Title of the Paper: Influence of the Feed Rate on the Workpiece Surface in Face Milling

Authors: Janos Kundrak, Csaba Felho

Abstract: Because of the diversity of cutting processes, the created tools imprints on the surfaces – which affect the formation of the topography – can take many forms. Besides this, roughness values of machined surfaces are different along the path of the cutting edge and when measured at different directions of the surface of the workpiece at face milling due to the special movement of the tool, therefore the knowledge of and the ability to plan the roughness characteristics of the surface are extremely important. Here, topography of face milled surface is studied with theoretical and experimental methods. The investigations covered the determination of 2D and 3D theoretical values of roughness indexes using a method developed by the authors, and the completion of cutting experiments and analysis of roughness of the obtained machined surfaces. The results obtained by modeling were compared with measurement data from the machined surfaces. In this publication, results of surface analysis when cutting with one and two circular inserts are introduced. The tests were performed by varying the value of the feed per tooth (fz) and the effect of the increase of fz on surface roughness characteristics (topography) were analyzed.

Keywords: Face Milling, Surface Roughness, 2D and 3D Roughness Parameters

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #24, pp. 183-191


Title of the Paper: Development of Information System with a Digital Library Based on the Bicharacteristics Numerical Method

Authors: Zhanar Akhmetova, Seilkhan Boranbayev, Serik Zhuzbaev, Sarsenov Bakytbek

Abstract: This paper discusses the development of an information system based on bicharacteristics method. The bicharacteristics method is one of the most convenient methods for software development. The developed information system has a digital collection of solutions visualization of particular problems in the dynamics of homogeneous elastic media. This information system is used in the calculation of building structures in engineering practice as well as in engineering problems and generally for research in their respective industries.

Keywords: information system, visualization, engineering, numerical methods, digital library, non-stationary wave’s propagation

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #23, pp. 177-182


Title of the Paper: Using the Transformation Matrices not Only to Derive the Motion Equations

Authors: Jiri Zatopek

Abstract: This article introduces different ways of transformation matrices use. The first utilization is to determine the motion equations of the complex mechanical structure. Analysed model is designed in 3D CAD system SolidWorks. It consists of seven main physical objects. The corresponding inertia/pseudo-inertia matrix is derived for each of them with the aid of transformation matrices. These matrices are further used to derive the motion equations. The ball position scanning by camera system provides another possibility of the transformation matrix use; the camera local coordinate system is different against the plate local coordinate system and it is necessary to recalculate the real ball position. The final mentioned use of transformation matrices is in the determination of ball falling direction - it is valid only in case of its zero initial velocity.

Keywords: Motion Control, Transformation Matrix, Motion Equations, Gradient, Simulation, Matlab/Simulink

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #22, pp. 169-176


Title of the Paper: FEM-DBEM Procedure for Crack Analysis in Baffle Module of Wendelstein 7-X

Authors: R. Citarella, V. Giannella, M. Lepore, J. Fellinger

Abstract: “Wendelstein 7-X” is the world’s largest nuclear fusion experiment of “stellarator type” in which a hydrogen plasma is confined in a magnet field, generated with external superconducting coils, allowing the plasma to be heated up to fusion temperature. The water-cooled Plasma Facing Components (PFC) protect the Plasma Vessel (PV) against radiative and convective heat from the plasma. After the manufacturing process of the heat shields and baffles, several cracks have been found in the braze and in the cooling pipes. Due to heat loads occurring during each Operational Phase (OP), thermal-stresses are generated in the heat sinks, brazes and cooling pipes, that encourage cyclic crack-growth and, eventually, the water leak through the pipes. The aim of this study is to predict the operational limits of the baffles and heat shields under cyclic heat loads, by using a numerical model based on a FEM-DBEM approach, in order to provide an assessment on the risks of premature failure for segments assembled in the PV.

Keywords: FEM-DBEM approach, plasma vessel, plasma facing components, crack analysis

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #21, pp. 160-168


Title of the Paper: Artificial Neural Networks to Correlate Hot Deformation Cooling Rate and Deformation Temperature on Continuous Cooling Transformation of 22MnB5 Steel

Authors: Barcellona Antonio, Palmeri Dina

Abstract: The 22MnB5 steel is a hot stamping steel developed with the aim to satisfy the increasing request of the automotive industries to apply materials able to guarantee higher passive safety and weight reduction. The hot stamping process is an innovative forming technique in which the deformations are carried out at elevated temperature and allows to achieve high strength components. The experimental characterization of the material response, at different values of the main variables of process, may result both expensive and time consuming, but the mutual effects evaluation of the deformation parameters and the phase transformations are necessary to produce components within the desired properties. The developed model, by means of a neural network approach with a Bayesian framework, is able to predict the hardness and the specific microstructure of 22MnB5 steel as a function of the main parameters that are fundamental in hot stamping processes, thus overcoming the lack of fit of the existing numerical models.

Keywords: Artificial Neural Network, 22MnB5, Continuous Cooling Transformation, Hot Prestrain

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #20, pp. 154-159


Title of the Paper: Experimental and Numerical Study of Velocity Profiles in FGD Reactor

Authors: Jan Novosád, Petra Dančová, Tomáš Vít

Abstract: This article describes the investigation of velocity fields inside the flue gas desulfurization reactor. This reactor is self-constructed for using as experimental verification tool in research of modeling the desulfurization process. During the experimental study the velocity field at the inlet of the reactor and inside the spray zone were measured. Obtained values of velocity at the inlet were used to set boundary conditions for CFD. For CFD modelling of the flow inside the reactor software OpenFOAM with its utilities was used. CAD model of the reactor was edited to the simplified geometry of fluid inside and several different computational meshes with different element size were created. After that CFD simulations were performed to study the effect of mesh size to results of simulations (velocity fields). At the end results obtained from experiments and from CFD were compared. Based on the comparison the requirements for the computational mesh and CFD solver parameters to gain good agreement with the real state were specified.

Keywords: desulfurization, reactor, flow, velocity profile, CFD, OpenFOAM

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #19, pp. 148-153


Title of the Paper: Numerical Analysis of Fatigue Degradation of Screw Pump

Authors: Stepan Major, Pavel Cyrus, Roman Dostal

Abstract: In this article numerical analysis of fatigue damage of screw pump is discussed. The process of fatigue degradation of the screw is example of fatigue crack growth in notched bar under biaxial loading. This biaxial loading consists from axial tension loading and torsion for one screw systems and in the case of machines with several screws the loading consist from bending and torsion. The fatigue process was studied using computational methods. The screw pump used in this study were made from two different alloys and the effect of various surface layers on the fatigue resistance was also studied. The theoretical model is in a good agreement with experimental results.

Keywords: Fatigue Life, Finite Element Analysis, Screw Pump, Smith–Watson–Topper Criteria

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #18, pp. 142-147


Title of the Paper: Numerical Simulation of Reinforced Concrete Beam with Utilization of Elasto-Plastic Material Model of Concrete

Authors: Filip Hokeš, Martin Hušek, Petr Král, Jiří Kala

Abstract: Design of concrete structures in accordance with standards may suffer from less effectiveness of a final design. More realistic simulation of behaviour of structure can be achieved by incorporation of nonlinear material model within numerical simulation of given problem. However, this approach is connected with several difficulties. First of all, the utilization of nonlinear material model is confronted with problem of existence of material parameters that are not often known in advance. Second, the introducing reinforcement into finite element model is complicated by the choice of the correct element type and the correct bond between elements of both meshes. First of the above mentioned problems can be handled with by applying an inverse analysis based on utilization of optimization techniques. Such process of the inverse identification is based on the comparison of the experimental and numerical load displacement curves and minimization of the difference between them. The problem of the modelling of reinforcement can be resolved in more possible ways. The article shows the solution with simple truss elements that are modelled in according to finite element mesh of the concrete beam.

Keywords: ANSYS, reinforced concrete beam, optimization, identification, elasto-plastic material model

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #17, pp. 136-141


Title of the Paper: Design and Analysis of Watertight Bolted Pressure Chamber

Authors: Mootaz. E. Abo-Elnor

Abstract: Water tightness is one of the challenges in design of submerged vessels. In this paper, a pressure proof test chamber is designed in order to test water tightness of a hatch and also for testing water prove of hull penetrators which used in submerged vessels for crossing sensor cables through the pressure hull. The test chamber is designed such that its interior simulates the wet environment (surrounding water environment) and its exterior simulates the watertight proof environment (the dry environment). This test chamber is designed to withstand internal pressure up to 20 bar; i.e. 200 meter submerge. First a three-Dimensional model of the test chamber is made using AUTODESK INVENTOR and then stress analysis is carried out using ANSYS solver provided in AUTODESK INVENTOR. Contact analysis between the pressure chamber and the assembly hatch is also carried out to examine the gap between contact surfaces of bolted region of the test chamber. Chamber shell and heads thicknesses calculated according to ASME code section-VIII Div.2 and verified through the finite element analysis. The analysis shows the ability of the test chamber to withstand the applied pressure and the effectiveness of the bolted assembly hatch.

Keywords: pressure chamber, contact analysis, assembly hatch

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #16, pp. 129-135


Title of the Paper: Normal Impact of a Viscoelastic Spherical Shell Against a Rigid Plate

Authors: Y. Rossikhin, M. Shitikova, Duong Tuan Manh

Abstract: In the present paper, the normal impact of a viscoelastic spherical shell upon a rigid plate is investigated using the wave theory of impact. The model developed here suggests that after the moment of impact quasilongitudinal and quasi-transverse shock waves are generated, which then propagate along the spherical shell. The solution behind the wave fronts is constructed with the help of the theory of discontinuities. Since the local bearing of the material of the impactor is taken into account, then the solution in the contact domain is found via the modified Hertz contact theory involving the operator representation of viscoelastic analogs of Young’s modulus and Poisson’s ratio.

Keywords: Fractional derivative standard linear solid model, Impact, Viscoelastic spherical shell

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #15, pp. 125-128


Title of the Paper: Predictive Control with Filtered Input and Output Variables in Prediction Equations

Authors: Marek Kubalčík, Vladimír Bobál

Abstract: The paper is focused on an implementation of a predictive controller with a colouring filter C in a disturbance model. Both single-input-single-output (SISO) and multi-input-multi-output (MIMO) cases were considered and analysed. The filter is often essential for practical applications of predictive control based on input-output models. It is commonly considered as a design parameter because it has direct effects on closed loop performance. In this paper a computation of predictions for the case with the colouring polynomial is introduced. The computation is based on particular models of the controlled systems in the form of transfer function in case of SISO system and matrix fraction in case of MIMO system which are commonly used for description of a range of processes. Performances of closed loop systems with and without the colouring polynomial in the disturbance model were also compared.

Keywords: predictive control, disturbance modelling, colouring polynomial, filtering of variables, transfer function models, matrix fraction models

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #14, pp. 114-124


Title of the Paper: Nondestructive Defect Evaluation of Polyethylene Pipes

Authors: Zhibin Zhu, Shuncong Zhong, Xu Qiu, Yuexin Huang, Xiaoxiang Yang

Abstract: We report an approach for nondestructive testing and evaluation of polyethylene pipes by using active infrared thermography technique, in which an electrical heating bar and a high-sensitivity high-speed infrared camera was respectively used as the novel thermal excitation source and the detector. Mathematical morphology is employed for defect feature extraction from thermographic images and realized the automatic evaluation of PE pipe defects. Various defects with different dimensions in PE pipes were investigated and they would affect the thermal distributions from which the relationship between thermographic images and defect sizes and locations was established. A finite element model was built to mimic the transient heat transfer in PE pipes. The finite element simulation results are well agreed with the one obtained from experiments and it demonstrated that finite element method can be an effective method to analyze infrared imaging. To further verify the capability of developed active infrared thermography in defect detection of PE pipes, defects in heat fusion joints of PE pipes were fabricated and measured. The experimental results showed that active infrared thermography based on an electrical heating bar, with defect extraction by mathematical morphology, could provide a novel tool for nondestructive evaluation and health monitoring of PE pipes.

Keywords: Active Infrared thermography, Mathematical morphology, Polyethylene pipes

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #13, pp. 107-113


Title of the Paper: Determination of Self-Excited Vibration Criterion for Strip Rolling Mills

Authors: Ling Ma, Yongqin Wang, Yuanxin Luo, Xingchun Yan

Abstract: Self-excited vibration has been occasionally observed with a nature frequency of the mill stand during the strip rolling process. The root cause of this phenomenon has not been clearly explained yet. In general, it is related with rolling reduction ratio, rolling speed, frictional condition and material mechanics etc. According to the evolution of vibration amplitude, self-excited vibration can be classified into stable type with decreasing amplitude and unstable type with increasing amplitude by a critical condition where the vibration amplitude keeps unchanged. This critical condition is a criterion which can distinguish the type of self-excited vibration and help to escape the unstable self-excited vibration as well as prolong the rolling mill’s lifetime. This paper is aimed to determine the self-excited vibration criterion of a typical rolling mill. Based on different solutions to the mill’s differential vibration equations under different operational parameters, critical conditions mean that characteristic roots’ real parts are either zero or negative. They constitute the criterion curve in corresponding operational parameter field. The differential vibration equations of rolling mill are simplified as a set of second-order equations by assuming that the deformation region of the strip is equivalent to springs and damps. Then the equivalent damping and stiffness matrices can be calculated using 2D rigid-plastic FEM through applying perturbations of roll displacement and velocity. Compared with measured data, the predicted self-excited vibration criterion is proved to be reasonable. It’s believed that this research will be meaningful to optimize the rolling operational parameters and avoid the occurrence of unstable self-excited vibration.

Keywords: Rolling mill, Self-excited vibration, Perturbation, Rigid-plastic FEM

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #12, pp. 97-106


Title of the Paper: Probability Calculation for Natural Frequency of Anisotropic Stator Core of Large Turbo-Generator

Authors: Yixuan Wang

Abstract: Techniques for vibration reduction and design of stator core require knowledge of its modal frequencies, which depend on the geometry shapes, dimensions and material properties. The material properties of stator core are mainly related to its laminated process and assembly as well as the operating temperature of turbo-generator. It is found that the generally accepted value of material properties is not valid for the stator core with laminated silicon steel slice and operating at about 110-120 Celsius. This paper simply summarizes the method of determining elastic constants of stator core material, and then introduces a simple and effective method for the calculation of the modal frequencies of stator core. The material model of stator core is thought anisotropic. The elastic modulus, Poisson’s ratio, and mass density are all considered as uncertainty variables, obeying Gaussain distribution, and changing in the possible range; and then ANSYS workbench 14.5 program is used to determine the resonant frequencies and corresponding probability of stator core ,and response surfaces of natural frequencies vs. elastic constants by statistical method (Six Sigma Analysis). The results have an important guiding role for the laminated structure design, manufacture process, the fixedness and the vibration isolation design of stator core.

Keywords: Large turbo-Generator, Anisotropic Stator Core, Material Properties, Natural Frequency, Six Sigma Analysis

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #11, pp. 85-96


Title of the Paper: Cumulative Damage Assessment to Airdrop Vehicle Hull for the Landing Process

Authors: He Jian, Ma Ji-Sheng, Wu Da-Lin, Deng Shi-Jie

Abstract: In order to test the shock and vibration resistance performance of an airdrop vehicle, one test way is by actual equipment airdrop ,but this way needs large human and financial resources and the experimental conditions can not be controlled well, numerical simulation analysis become another effective way. This article first built the dynamic model of the whole vehicle based on virtual prototype technology, analysis the airbag force at vehicle landing process by tools of finite element method, next did the dynamic simulation to the vehicle landing process and got the loads time history on the hull, then applied these loads on the finite element model of the hull and did the transient dynamic response to the model, got the stress and strain time history of the hull, last did the cumulative damage assessment based on the strain time history of the hull combined the Lemaitre damage model and the material parameter.The calculation results show that the damage variable D has a linear relationship with the number of landing times and after 6 times of limit landing process, the part of hull will failure.The research can provide reference to the shock and vibration test for large airdrop equipment.

Keywords: Airdrop vehicle, Dynamic, Finite element, Shock, Damage Assessment

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #10, pp. 76-84


Title of the Paper: Impact of an Internal Polymeric Liner on the Fatigue Strength of Pressure Vessels Under Internal Pressure

Authors: M. A. Bennani, Abdeslam El Akkad, Ahmed Elkhalfi

Abstract: This paper presents a new original idea about the fatigue strength of pressure vessels. It tries to examine the impact of the internal liner on the fatigue strength of pressure vessels. The liner is mainly used to protect the structure against corrosive products such as hydrocarbons. This study states that the installation of a super-elastic polymer coating can help to solve several problems related to pressure vessels. In addition to the protection against corrosion, this coating may contribute to the improvement of the fatigue strength of structures as well as the prevention of sudden leaks. Moreover, this paper has proposed two main examinations; the first is an attempt to compare different susceptible materials used as liners. Besides, parametric study is performed during the second examination with the previously selected material for the optimal thickness.

Keywords: pressure vessel, fatigue analysis, liner, coating, failure

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #9, pp. 67-75


Title of the Paper: Usage of Finite Grid Solution for Vibration of Rectangular Plates on Elastic Foundations

Authors: Abdulhalim Karasin, Rehber Akdogan, Polat Gülkan, Murat Arda Ugurlu

Abstract: In engineering practice, beside static case often dynamic effects must be taken into consideration for plate design problems. Plate vibration solutions have been available for regular geometries for a long time, but where irregular boundaries or partial contact are encountered difficulties arise because it will be necessary to describe the governing equation of motion in a general mathematical form. This is not easy. The intention of this study is to extend analytical solutions of the discrete one-dimensional elements resting on elastic foundation for solution of plate vibration problems. The solution can be stated as an extension of the so-called discrete parameter approach where the physical domain is broken down into discrete sub-domains, each endowed with a response suitable for the purpose of mimicking problem at hand. The numerical results of this solution technique show versatile and powerful analysis capacity to solve various vibration problems including bi-directionally stepped and plates on non-homogeneous elastic foundation.

Keywords: Grillage of beams, vibration, plates with abrupt changes in thickness, complex support conditions, finite grid solution

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #8, pp. 60-66


Title of the Paper: A Method for Determining the Key Structure of 3D Parts Based on Rough Set and Concept Lattice

Authors: Changxing Fan, Qiang Wu, Yan Dong

Abstract: The key of parts model retrieval is how to complete the similarity calculation as quickly and accurately as possible. The similarity calculation is closely related to the model feature extraction. Concept lattice is a powerful tool in knowledge processing and analyzing, its reduction can improve the efficiency. In this paper, by mapping relationships among the parts functional surfaces and the positions to the binary formal context, a concept lattice of 3D parts structure model was built, authors use discernibility matrix of rough set in simplifying the concept lattice of formal context based on parts assemble structure, and then quickly determine the key structure to reflect the characteristics of the parts, which has very strong regularity and lays the basis for the efficient parts query.

Keywords: Mechanical parts assembly structure, Concept lattice, Discernibility matrix, 3D parts key structure, Rough set, Simplifying

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #7, pp. 54-59


Title of the Paper: Optimization of Tool Wear Rate During Electrical Discharge Machining of Advanced Materials Using Taguchi Analysis

Authors: Vijaykumar S. Jatti, T. P.Singh

Abstract: In electrical discharge machining tool wear is a major problem. The contribution of the tool cost in the total operation cost is approximately 50%. Because of tool wear the geometrical dimensions and form of the tool are not reproduced on the workpiece. Due to these reasons the tool wear has to be carefully handled while planning electrical discharge machining operations. In view of this, present study uses Taguchi’s method to optimize the electrical discharge machining process variables for achieving minimum tool wear rate. NiTi alloy, NiCu alloy and BeCu alloy were consider as the workpiece materials and electrolytic copper was considered as tool electrode. Electrical parameters considered for the study includes gap current, gap voltage, pulse on time and pulse off time along with workpiece electrical conductivity. Experiments were carried out as per the Taguchi’s L18 orthogonal array. The most significant parameter that affects the tool wear rate was obtained by Taguchi’s signals to noise ratio and analysis of variance methods. Based on the statistical analysis it was found that work electrical conductivity, gap current, and pulse on time were the most significant process parameters that affects tool wear rate. The obtained optimal parameter setting provides minimum tool wear rate.

Keywords: NiTi alloys, NiCu alloys, BeCu alloys, Taguchi approach, Analysis of variance, Tool wear rate

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #6, pp. 46-53


Title of the Paper: Analytical Solution for MHD Flow Due to a Permeable Stretching Surface Embedded in a Porous Medium

Authors: M.Thiagarajan, K. Senthilkumar

Abstract: This paper is devoted to introduce analytic solutions by Differential Transform Method-Pade approximants with theoretical study for the problem of the hydromagnetic flow due to a permeable stretching surface embedded in a porous medium in the presence of transverse magnetic field. The governing momentum equation which is a nonlinear partial differential equation is reduced into a nonlinear ordinary differential equation by using similarity transformation and then solved numerically by DTM-Pade. The accuracy of present method is tested by numerical shooting method and the results are found to be in an excellent agreement. Numerical results are displayed by means of graphs. The effect of porous parameter, magnetic parameter and suction/injection parameter on skin friction and velocity are thoroughly studied.

Keywords: MHD, Porous medium, DTM, Pade approximant, Magnetic parameter, Skin friction

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #5, pp. 39-45


Title of the Paper: Parametric Study of Analyses of Linear Inhomogeneous and Nonlinear Half-Space in Foundation-Subsoil Interaction

Authors: Jana Labudkova, Radim Cajka

Abstract: The solution of tasks of interaction of foundation and subsoil is more difficult the less accurate the input data. The modulus of deformability of the modeled area of subsoil varies smoothly with increasing depth. It was resolved by use of an inhomogeneous half-space. Two sets of FEM analyses were performed. Nonlinear elastic isotropic homogeneous half-space was applicated for the first set of FEM analyses. Linear elastic isotropic inhomogeneous half-space was applicated for the second set of FEM analyses. The parametric study shows comparison of resulting slab deformations obtained by analyses of homogeneous and inhomogeneous half-space.

Keywords: Foundation structure, Soil – Structure Interaction, Contact Stress, 3D FEM Elements

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #4, pp. 30-38


Title of the Paper: Multi-Objective Optimization of Gatling Gun Tripod Based on Mesh Morphing and RBF Model

Authors: Binbin Hua, Ruilin Wang, Yongjian Li, Xiaoyong Kang, Hao Tian

Abstract: Large elastic deformation of Gatling gun tripod during the shooting process is an important factor affecting the firing accuracy. Mesh morphing and approximate model technique are comprehensively applied to the multi-objective optimization of gun tripod for improving its rigidity aiming at this problem. After finite element model of tripod is established, mesh morphing technique is utilized to define shape variables. The traditional dimension variables together with the shape variables defined by utilizing mesh morphing technique are combined to act as the design variables. Then optimal variables are screened out by Plackett-Burman design. Hammersley sampling is employed to generate uniformly distributed sampling points for fitting high-precision RBF model. Multi-Objective Genetic Algorithm is adopted to perform the optimization in which the longitudinal stiffness and transverse stiffness of tripod are defined as the objective functions while the mass of tripod leg is defined as a constraint function. The optimal solution can turn out that the longitudinal stiffness and transverse stiffness of tripod can be improved simultaneously by applying the proposed methodology to the multi-objective optimization for gun tripod.

Keywords: Mesh morphing, Design of experiments, RBF model, Multi-objective optimization

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #3, pp. 22-29


Title of the Paper: Experimental Study on Vibrations of Shafts Suspended by Regular and Irregular Bore Journal Bearing

Authors: E. M. Attia, A. N. Mohamed

Abstract: Practical applications of machine elements supported by a flexible support are rotating shafts mounted on bearings. The bearings in general are journal or rolling which have stiffness and damping characteristics. The shaft itself has hysteric damping due to the deflection and whirling. The problem of journal bearing vibrations is a great importance in whirling of the rotating shafts and it is important to minimize the vibrations acting on that bearings. A very recent method for doing this is the creation of smart journal bearings using irregular surface. This type of surfaces will cause an alteration in the dynamic properties of the journal bearing and thus the dynamic performance of the rotating shaft. This paper introduces an experimental model of whirling flexible shaft carrying a load at a mid-point and is supported by two identical journal bearings at its ends. Two types of journal bearings are fabricated, the first one its bore was made from regular surface and the second its bore was made from irregular surface. The analysis here is based on measuring the vibrations in the presence of regular and irregular bore journal bearing. Hammering and run - up test was made and analyzed for the two cases. Also effect of changing speed and load acting on each bearing was studied experimentally. An overall vibration is measured for different loads and the results were compared as the shaft is mounted by regular bore bearing or irregular type.

Keywords: Journal Bearings, Regular, Irregular, Vibrations, Dynamic, Measurements

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #2, pp. 8-21


Title of the Paper: Lateral Stability Analysis of Telehandlers Based on Multibody Dynamics

Authors: Haoliang Guo, Xihui Mu, Fengpo Du, Kai Lv

Abstract: At the beginning, this article analyzed the lateral stability of telehandlers, and reached the following results: the critical overturning angle, the critical sliding angle, and the conditions of sliding happen before overturning. Then, the ADAM virtual prototype of telehandlers was built based on the multibody dynamics model, and the dynamic simulation of the lateral stability of telehandlers was carried out, and then we got the rule of that the right tire reacting force change with the critical overturning angle with frame leveling or not. Base on the ‘UA’ model of tire, we studied the influence of vertical stiffness and lateral stiffness on the lateral stability of telehandlers. The result of virtual simulation method was compared with that of the theoretical calculation and platform experiment. It can be seen that the result of the virtual simulation method is closer to the actual situation, and can shorten the development process and reduce the cost, which can guide the structure design of telehandlers more scientifically. This article can also provide reference for the design of the lateral stability of the rear axle articulated vehicles.

Keywords: Telehandlers, Lateral Stability, ADAMS, Overturning Angle, Multibody Dynamics

WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 11, 2016, Art. #1, pp. 1-7


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