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This contribution deals with the modal analysis of ACSR conductor using the finite element method (FEM) and experimental measurements of eigenfrequencies. In numerical experiments for the modelling of the conductor the material properties of the chosen conductor cross-section are homogenized by the Representative Volume Element (RVE) method. The spatial modal analysis of the power line is carried out by means of our new 3D FGM beam finite element and by standard beam finite element of the commercial software ANSYS. Experimental measurements are also carried out for verification of the numerical calculation accuracy.

This paper presents the preparation phase for model of transmission tower lattice construction using ANSYS APDL environment. Beam elements are used for the model which introduce complications in the preparation phase because of the need to define the beam shape. Considering that the lattice construction of the transmission tower consists of hundreds of trusses it is obvious that some auxiliary tool is necessary for preparation of such model in ANSYS APDL. This tool was programmed in SW Wolfram Mathematica.

The article describes the thermo-hydraulic analysis of a dry cask storage building that is used for the storage of depleted nuclear fuel to determine the viability of a buoyancy driven cooling system. The analysis is performed in the form of steady-state CFD simulations. The resulting temperature distributions are them evaluated based on required operation criteria.

The contribution deals with mechanical simulation of clamps for overhead powerline AlFe conductors. The process of pressed joint creation for two AlFe conductors and tensile test of such system are simulated using ANSYS software. The obtained results are compared to given tensile strength of the clamp.

In this paper, the influence of torsional warping of thin-walled cross-sections of twisted Functionally Graded Material (FGM) beams with a longitudinal polynomial variation of the material properties on their eigenvibrations is investigated, considering the secondary deformations due to the angle of twist. The transfer relations needed for the transfer matrix method are derived. Based on them, the local finite element equations of the twisted FGM beam are established. The warping part of the first derivative of the twist angle, caused by the bimoment, is considered as an additional degree of freedom at the beam nodes. The focus of the numerical investigation, with and without consideration of the Deformation due to the Secondary Torsional Moment (STMDE), is on modal analysis of straight cantilever FGM beams with doubly symmetric open and closed cross-sections. The influence of the longitudinal variation of the material properties and the secondary torsion moment on the eigenfrequencies is investigated. The obtained results are compared with the ones calculated by a very fine mesh of standard solid and warping beam finite elements.

In this paper, results of numerical simulations and measurements are presented concerning the non-uniform torsion and bending of an angled members of hollow cross-section. In numerical simulation, our linear-elastic 3D Timoshenko warping beam finite element is used, which allows consideration of non-uniform torsion. The finite element is suitable for analysis of spatial structures consisting of beams with constant open and closed cross-sections. The effect of the secondary torsional moment and of the shear forces on the deformation is included in the local finite beam element stiffness matrix. The warping part of the first derivative of the twist angle due to bimoment is considered as an additional degree of freedom at the nodes of the finite elements. Standard beam, shell and solid finite elements are also used in the comparative stress and deformation simulations. Results of the numerical experiments are discussed, compared, and evaluated. Measurements are performed for confirmation of the calculated results.

In the contribution, piezoelectric structure modeled by 2D solid finite element is presented. Stiffness, damping and mass matrices of 2D piezoelectric element were implemented into finite element method (FEM) code MultiFEM, where transient and modal analyses are performed. From modal analysis eigenvalues and eigenvectors are used to develop model order reduction (MOR). MOR model is transformed to state-space model which is more suitable for control design and analysis.

The actuator of the angle of rotation or torque is presented that consists of two identical prestressed polymer springs of negative thermal expansion coefficient and a perfectly rigid angled beam in the shape of an inverted letter T. A mathematical-physical model for thermoelastic linear and nonlinear analysis of the torsional actuator is compiled, the result of which are the values of the action angle of rotation and torque of the actuator. The action is achieved by heating the polymer springs with a negative thermal expansion. The results of semianalytical models that can be used for automatic actuator control were verified by numerical analysis using the finite element method. The proposed torsion actuator shows a relevant action already at low warming of the nylon springs.

The paper presents the numerical simulation of thermo-hydraulic behaviour of coolant in nuclear reactor VVER-440 under reactor pool filling conditions. Temperature distribution and mixing of coolant with different temperatures during filling process are discussed.

In this work, creation process and structural changes of twisted polymeric fibers was investigated. In order to describe the structural changes, the X-ray diffraction was used on a set of specimens that are fabricated by twisting the straight nylon 6,6 where number of turns was changed gradually. The experimental measurement confirmed phase change dependence on number of turns.

The paper deals with modeling and simulation of the connection of piezoelectric materials, FGM materials and LQR control, using state-space model, which is built by modal truncation MOR method. FEM equations of piezoelectric finite beam were implemented in FEM program MultiFEM written in Wolfram Language. Modal truncation MOR method, which uses results from modal analysis, is also implemented in program Wolfram Mathematica. Simple piezoelectric structure is analyzed in numerical experiments, where FEM results are compared with MOR results.

Torsional properties of prismatic shafts are typically analyzed by assuming rigid in-plane rotations of the cross-section accompanied with appropriate out of plane warping deformations. The most frequently applied strategy in that field is Vlasov’s theory of torsion, where warping is described by a warping function which is weighted by the derivative of torsion angle. An alternative theory proposed by Benscoter uses an independent parameter to quantify the axial distribution of warping. Both these approaches return acceptable results in a static analysis of long and moderately short shafts, but turn out to be insufficient for accurate predictions of vibrational frequencies in dynamic applications. This is especially true for shafts with thin-walled box-type cross sections, where considerable qualitative and quantitative discrepancies are observed in resonance curves. Neither the number of resonance peaks nor their location matches, indicating fundamental problems with the underlying torsion theories. It turns out that in-plane distortional effects with their associated warping deformations influence the results considerably. Therefore, we propose to include those higher order beam effects by extracting distortional and warping deformations from a reference beam problem which is dynamically analyzed using 3D elasticity theory. From that a higher order beam theory can be derived in a straight forward manner, where each warping and distortional mode is quantified axially using generalized degrees of freedom. This formulation is convergent with respect to mesh refinement and the number of cross section modes, showing resonance curves in good accordance to 3D continuum results.

Actuator is a mechatronic system that transforms one type of energy into mechanical displacement and mechanical force. Nowadays, these actuators can be made of Functionally Graded Materials (FGM) to ensure the simple shape of the actuator and to improve its effectiveness, particularly for microsystems. FGM is built as a mixture of two or more constituents, which have almost the same geometry and dimensions. The variation of macroscopic material properties can be induced by variation of both the volume fractions and material properties of the FGM constituents. The paper deals with a new approach in analysing of the systems made of FGM using our new beam finite elements. Multiphysical analysis (weak coupled electro-thermo-mechanical analysis) and spatial continuous variation of material properties are supported. The analysis of the microactuator with a constant cross section made of FGM is presented in the paper. This simple-shaped actuator is supplied by electric current and the efficiency of the actuator is optimized. The solution results will be compared with those obtained by using solid elements of a FEM commercial program.

Gradual twisting of straight nylon composite fishing line results in a prestressed spring with negative thermal expansion (Haines et al. in Science 343:868–872, 2014 [1]). If the prestressed spring is stretched by the tensional load, then after heating it is shortened while doing mechanical work. For this property, it is possible to use it as a heat-controlled linear actuator (an artificial muscle). Another positive factor of these springs is that they have a great damping effect. This article deals with the methodology for determining the basic dynamic parameters of the artificial muscles in the form of nylon springs (Murin et al. in Adv Mater Lett 8:635–640, 2017 [2]). Based on the tensile test, the linear stiffness of the nylon spring, which is compared to the stiffness evaluated by the dynamic vibration test, is determined. From the vibration test, it is additionally possible to determine the damping factor when considering the simplified linear viscous damping model. Using these parameters, modelling and numerical simulations of the oscillating nylon spring systems is done as a discrete dynamic system. The eigenfrequency of the dynamic system is measured and compared with the results obtained by the numerical analysis.

Coiled fishing line actuator is created by twisting the straight nylon fishing line under a constant tensile preload. Actuator looks like extension spring and its function is controlled by temperature changes. This article presents a brief introduction to this type of actuator and its basic parameters.

In this paper, the influence of longitudinal variation of material properties on the deformation and stresses of thin-walled non-uniformly twisted Functionally Graded Material (FGM) beams is investigated. The longitudinal variation is described by a polynomial. Secondary deformations, resulting from the angle of twist, are considered. The transfer relations are derived and used for establishing finite element equations for non-uniformly twisted FGM beams in local coordinate systems. The warping part of the first derivative of the twist angle, caused by the bimoment, is considered as an additional degree of freedom at the nodes of the beam elements. The numerical investigation is performed with consideration of the Secondary Torsional Moment Deformation Effect (STMDE). It is focused on elastostatic analysis of straight cantilever FGM beams with doubly symmetric open as well as closed cross-sections. A very strong effect of the longitudinal variation of material properties on the twist angle and bimoment normal stresses is originally studied and presented. The results are compared with the ones obtained by a very fine mesh of standard solid and shell as well as warping beam finite elements.

Mechanical properties of slender, prismatic structures are typically analyzed based on classical beam mechanics (Timoshenko’s shear force bending, Vlasov’s theory of warping torsion, …). There it is assumed that the cross-section remains rigid in its projection plane and in-plane distortional deformations of the cross-section are neglected. Such a model is predictive in case of static gradually distributed loading, and solid cross-sections, however, in case of thin-walled crosssections and dynamic loading severe deviations might occur. Therefore, a generalized beam theory is proposed, where warping fields and accompanied distortional fields of the cross-section are axially distributed each based on one generalized degree of freedom. The evaluation of pairs ofwarping and distortional fields in ascending order of importance is performed using a specific reference beam problem (RBP), where three-dimensional elasticity theory is applied in connection with semi-analytical finite elements (SAFE). Convergence of the resulting formulation is ensured by increasing the number of contributing pairs of warping and distortional fields. The resulting formulation yields significantly better results compared to classical beam mechanics especially in the dynamic regime.

This paper presents real mechanical system with physical parameters (mass, stiffness, damping) which were experimentally determined. System is composed of the steel cantilever beam with added mass at the beam's free end and further mass suspended on the beam by means of the tension spring. Simplified discrete linear mathematical model of the system is described by two 2nd order linear ordinary differential equations which were converted in the form of four transfer functions. These transfer functions were used for parameter identification of the system from measured input-output dynamic data using software Matlab. Values of the measured and identified parameters were compared. Finally, the dynamics of the mathematical model with measured and identified parameters was compared with measured dynamic data on real mechanical system.

The paper presents our new Functionally Graded Material (FGM) beam finite element that can be used for elastic-static, modal and buckling analysis of single beams or spatial beam structures. The material properties in a real beam can vary continuously in the longitudinal direction, while the variation with respect the transversal and lateral directions is assumed to be symmetric in a continuous or discontinuous manner (Murin et al., 2016). An application to elastostatic and modal analysis of high-voltage lines (single, double and triple bounded) with heterogeneous cross-sections is presented. The heterogeneous material properties of the cross-section are homogenized using the extended mixture rules. A linearized elastostatic analysis of power lines with the effect of tensile axial forces is proposed. Further, the axial, flexural and torsional eigenfrequencies and eigenmodes are calculated. The corresponding results of simple and bundle power lines obtained by our proposed finite element are compared with the ones obtained with standard beam finite elements. Further, the accuracy and efficiency of our proposed beam finite element is evaluated and studied. The results of the chosen analyzed case are verified by measurements on real electric conductor.

This contribution contains the results of experimental measurements and modelling of torsional warping free vibrations of beams with rectangular hollow cross-sections. The experimental results are compared with results from a semi-analytical method, proposed by the authors, and from Finite Element (FE) computations by means of a standard commercial code. In these calculations, beam, solid, and shell elements are used. The semi-analytical calculations are based on the analogy between second-order beam theory, including consideration of the shear force deformation effect, and non-uniform torsion, considering the Secondary Torsion Moment Deformation Effect (STMDE). The influence of warping and of the STMDE on the torsional eigenfrequencies and eigenforms is evaluated. The difference between the measured and calculated eigenfrequencies is investigated and quantified.

In this contribution, the analysis of ice-shedding from Aluminium Conductor Steel Reinforced (ACSR) power lines is presented. The impact of the icing position on the overhead power lines, the resulting jump height, and impact on attachment tension points after ice-shedding is examined. In the numerical simulations the effective material properties of the ACSR conductor is calculated using the homogenisation method. Numerical analysis of one power line and double-bundle power lines with icing over the whole range or only on certain sections of single and double-bundle power lines are performed

This paper contains results of transient analysis of airflow around the ACSR power line cross-section in unsymmetric multi-span. The forces applied to the power line are obtained from CFD simulations, where the wind induced vibration is studied. Effect of these forces to the maximal displacement of the power line and the maximal mechanical forces in the points of attachment are studied and evaluated.

Requirements of increased productivity and flexibility in manufacturing processes reflect the concept Industry 4.0. Essential to achieving these targets is the implementation of intelligent and robust distributed control systems focused on interoperability and scalability. New approaches and technologies based on the Industrial Internet of Things (IIoT), cloud computing and Big Data are an emerging field of industrial control that comprises Internet-enabled cyber-physical devices with the ability to link new smart technologies. With this perspective, manufacturing devices can be easily monitored, operated and controlled even from remote locations. Conventional industrial control approach, that use programmable logic controller (PLC), is enhanced with intelligent industrial gateway IoT 2040 as a hardware and Node-RED software environment in order to provide interoperability, robust and reliable control system. Collected process data and parameters from embedded sensors and other connected devices can be quickly collected, processed, transformed and used for device control from remote production environment. This paper deals with an industrial gateway framework adopting the idea of Internet of Things for the development of robust industrial control approach. The concept is tested in real industrial environment.

Modern manufacturing industry is currently facing significant challenges with regard to the concept of Industry 4.0. The promise of increased productivity and flexibility in manufacturing processes can not be achieved without implementation of systems and advance methods based on smart technologies. Implementation of Industrial Internet of Things (IIoT), Condition Monitoring, Big Data, Cloud computing, virtual and augmented reality in maintenance processes will significantly increase the effectivy and quality of manufacturing processes as well as eliminate the human factor. Under this perspective, cyber– physical systems can be accessible from remote location; process paramters can be visualized at real time and prediction of unexpected production stop due to machine breakdown will be significantly reduced. The paper deals with the development of effective approach to real-time process control using parameters visualization of manufacturing process with the use of augmented reality smart glasses. Collected data from condition monitoring sensors from electric monorail system are evaluated in real time and visualized in the field of maintainer view. Critical values from field of sensors are highlighted and enable to predict manufacturing breakdowns. On real example from automotive industry will be demonstrated the signification and effectivity for maintenance of electric monorail system and potential for application in different types of modern industrial processes with the focus on rule-based intelligent predictive maintenance control.

A new actuator, consisting of two nylon springs, is designed in a form of the von Mises truss system. The nylon spring (an artificial muscle) is produced by twisting of the nylon line. As a result of the twisting into the prestressed spring, a new microstructure of the fibre has been formed. The spring, after its mechanical elongation, exhibits a negative temperature expansion after its warming. This is the main advantage for the practical applications. The heating of the actuator is realized by the electric wire, which is wound on the nylon springs. Semi analytical and numerical methods are used for geometric non-linear thermo elastic analysis of the actuator to obtain its deformation caused by the electro-thermo-mechanical loads. The calculated results are verified by the measurement on the real model. A very good agreement of both the results is obtained.A new actuator, consisting of two nylon springs, is designed in a form of the von Mises truss system. The nylon spring (an artificial muscle) is produced by twisting of the nylon line. As a result of the twisting into the prestressed spring, a new microstructure of the fibre has been formed. The spring, after its mechanical elongation, exhibits a negative temperature expansion after its warming. This is the main advantage for the practical applications. The heating of the actuator is realized by the electric wire, which is wound on the nylon springs. Semi analytical and numerical methods are used for geometric non-linear thermo elastic analysis of the actuator to obtain its deformation caused by the electro-thermo-mechanical loads. The calculated results are verified by the measurement on the real model. A very good agreement of both the results is obtained.

This article focuses on the modeling of the mixing processes of this cooling stripe and their effects on the RPV wall in a VVER440/213 Russian type PWR. The mixing processes are modeled in a transient thermo-hydraulic analysis which models the mixing of the coolant flows in the reactor pressure vessel and results in the overtime temperature and pressure fields within the RPV [1]. The analysis results show that the cooling stripe is not stationary. The turbulent mixing causes an unstable oscillatory motion of the cold stripe which has a notable effect on the RPV wall temperature distribution.

This paper proposes an efficient generalized beam theory (GBT) formulation, which accounts for cross-sectional deformations in slender prismatic structures. It was shown by the authors in a recent publication [1] that in-plane distortional deformations and accompanied out of plane warping deformations of the cross-section influence the accuracy of results in beam dynamics especially if thin-walled cross-sections are applied. The GBT formulation proposed in [1] overcomes the inaccuracies of classical beam mechanics, however, requires a two-dimensional plane discretization of the cross-section. The computational complexity can be reduced vastly, if thin-walled cross-sections can be discretized with one-dimensional elements. Consequently, this paper discusses an approach with a line mesh discretizing the cross-section and having six degrees of freedom at each node. The membrane part consists of massless micro-polar rotations (drilling rotations) and can be derived independently from the bending part, where a shear elastic formulation is selected.

In this contribution, which is an extension of author’s research [1,2], an influence of the in two and three directions varying material properties on non-uniform torsion of the Functionally Graded Material (FGM) thin-walled beams is originally investigated. Based on the semi-analytical solution of the fourth order differential equation for non-uniform torsion, the local finite element equations of the twisted FGM beam are presented, considering the non-uniform torsion with effect of warping and secondary deformations due to the angle of twist. The warping part of the first derivative of the twist angle caused by the bimoment is considered as an additional degree of freedom at the beam nodes. The Multi-Layers Method (MLM) [3], and the Reference Beam Method (RBM) [4] are extended for homogenization of the spatially varying material properties and relevant stiffnesses in the real beam onto effective longitudinally varying ones in the homogenized beam for the load case of non-uniform torsion. The focus of the numerical investigation, with consideration of the warping and Deformation Effect due to the Secondary Torsional Moment (STMDE), is on elastostatic analysis of straight FGM beams with rectangular hollow cross-sections. The influence of the variation of the material properties with respect to two or three directions on the angle of twist and the bimoment normal and torsional shear stresses is investigated. The obtained results are compared with the ones calculated by a very fine mesh of standard solid finite elements. This FGM warping non-uniform torsion beam finite element can be used not only in torsional analysis of general thin-walled beams but also in the design of FGM sensors and actuators in mechatronics.

In this contribution, results of elastostatic analysis of spatial composite beam structures are presented using our new beam finite element of double symmetric cross-section made of a Functionally Graded Material (FGM). Material properties of the real beams vary continuously in the longitudinal direction while variation with respect to the transversal and lateral directions is assumed to be symmetric in a continuous or discontinuous manner. Continuously longitudinal varying spatial Winkler elastic foundations (except the torsional foundation) and the effect of axial and shear forces are considered as well. Homogenization of spatially varying material properties to effective quantities with a longitudinal variation is done by the multilayer method (MLM). For the homogenized beam finite element the local stiffness matrix is established by means of the transfer matrix method. By the conventional finite element procedure, the global element stiffness matrix and the global system of equation for the beam structure are established for calculation of the global displacement vector. The secondary variables (internal forces and moments) are then calculated by means of the transfer relations on the real beams. Further, the mechanical stress in the real beams are calculated. Finally, the numerical experiments are carried out concerning the elastic-static analysis of the single FGM beams and beam structures in order to show the possibilities of our approach.

In this paper, the influence of torsional warping of the cross-sections of thin-walled twisted Functionally Graded Material (FGM) beams on their elastostatic behavior is investigated. The material properties are assumed to vary longitudinally. The variation is described by a polynomial. Secondary deformations, resulting from the angle of twist, are considered. The transfer matrix method serves as the analysis tool. The transfer relations are derived and used for establishing finite element equations for twisted FGM beams in local coordinate systems. The warping part of the first derivative of the twist angle, caused by the bimoment, is considered as an additional degree of freedom at the nodes of the beam elements. The numerical investigation is performed with or without consideration of the Secondary Torsional Moment Deformation Effect (STMDE). It is focused on elastostatic analysis of straight cantilever FGM beams with doubly symmetric open as well as closed cross-sections. The influence of the longitudinal variation of the material properties and of the secondary torsion moment on the deformation and stress state is investigated. The results are compared with the ones obtained by a very fine mesh of standard solid and shell as well as warping beam finite elements.

Content of the paper is oriented to calculation of elastic normal stress in the Functionally Graded Beams (FGM). Spatial variation of material properties is considered in the lateral, transversal and longitudinal direction of the straight beam. The displacements and internal forces are calculated using our new FGM finite beam element. Heterogeneous material properties are homogenized by extended mixture rules, laminate theory and reference volume element (RVE). Obtained results by our approach are evaluated and compared with the ones obtained by the 3D solid finite elements.

In this contribution modeling and simulation of surface acoustic waves (SAW) sensor using finite element method will be presented. SAW sensor is made from piezoelectric GaN layer and SiC substrate. Two different analysis types are investigated - modal and transient. Both analyses are only 2D. The goal of modal analysis, is to determine the eigenfrequency of SAW, which is used in following transient analysis. In transient analysis, wave propagation in SAW sensor is investigated. Both analyses were performed using FEM code ANSYS.