Justin Murin

Slovak University of Technology in Bratislava · Department of Automotive Mechatronics

This contribution extends the author’s previous research results concerning effect of spatially varying material properties on warping torsion of beams with open cross-section made of Functionally Graded Material (FGM). The author’s FGM WT beam finite element is used in the calculations of the primary quantities. The secondary deformations due to t...

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 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 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 o...

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...

The article presents original results of research of the dampers with passive and semi-active damping using polymer springs (also artificial muscles or nylon springs) with negative thermal expansion. Passive damping can be ensured by the strong damping effects of polymer springs. Semi-active damping can be provided by heating the springs from an ad...

The paper deals with the development of the finite element method (FEM) model of piezoelectric beam elements, where the piezoelectric layers are located on the outer surfaces of the beam core, which is made of functionally graded material. The created FEM model of piezoelectric beam structure is reduced using the modal truncation method, which is o...

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-uni...

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 const...

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 hea...

In this contribution, which is an extension of our research (Murin et al. in J Eng Struct 175:912–925, 2018 [6]), the influence of spatially varying material properties on torsional eigenvibration of the FGM beams is investigated. Based on the semi-analytical solution of the fourth-order differential equation for non-uniform torsion, the local fini...

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 derivati...

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...

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...

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...

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...

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 o...

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.

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 hundred...

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 micro actuator with constant cross section made of FGM is presented in the...

In the contribution, finite element beam with thick FGM core and thin piezoelectric layers is presented. Individual submatrices of FEM formulation are developed using concept of transfer functions and transfer constants. New beam element is implemented in FEM code MultiFEM, where state space model of FGM beam with piezoelectric layers with LQR cont...

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 n...

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 pre...

The application of first order shear beam theory in the analysis of beam structures made of functionally graded materials requires the access to homogenized stiffness quantities. These quantities depend on the cross-sectional shape and on the spatial variation of constitutive parameters. Some of these stiffness quantities can be evaluated easily by...

In the contribution, our 3D FGM Timoshenko beam finite element with 12x12 stiffness and mass matrices for doubly symmetric open and closed cross-section [1] is extended by warping torsion effect (non-uniform torsion) to 14x14 finite element matrices. A longitudinal continuous variation of effective material properties is considered by the finite el...

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 tran...

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 f...

The paper deals with finite beam element with piezoelectric layers and functionally graded material of core. In the process of homogenization of FGM core and piezoelectric layers direct integration method and multilayer method is used. There is also presented the derivation of individual submatrices of local stiffness and mass matrix, where concept...

The paper presents homogenization process of electric and thermal material properties in link structure made of Functionally Graded Material (FGM) with functionally prescribed change of these material properties in all three orthogonal directions inside the bar. Numerical experiment with developed link finite element (Finite Element Method – FEM) f...

The results of measurement of the eigefrequencies of the nylon actuators are presented considered free and damped eigenvibration. An analytical and numerical elastostatic and modal analyses of the nylon actuators are done and their results are compared with the measured ones. In numerical analysis, the finite element method is used.

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...

In this paper, the influence of the variable axial force and of the Secondary Torsion-Moment Deformation-Effect (STMDE) on the deformations of beams due to torsional warping is investigated. The investigation is based on the second-order torsional warping theory of doubly symmetric beams with thin-walled open or closed cross-sections. The effect of...

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...

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...

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 direct...

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 i...

In this contribution, a homogenized beam finite element for modal analysis considering a double symmetric cross-section made of a Functionally Graded Material (FGM) is presented. The material properties in a real beam can vary continuously in longitudinal direction while the variation with respect to the transversal and lateral directions is assume...

In this paper, the analysis of ice-shedding from ACSR conductors to its swing up height and vibration using Finite Element Method (FEM) is presented. For the numerical simulations the effective material properties of the ACSR conductor are calculated using the homogenisation method. Numerical analysis concerning vibration of one and triple-bundle c...

An efficient low-order finite shell element is derived for the thermo-elastic analysis of shell structures made of functionally graded materials or multilayer composites. It is based on a one-way coupling between the thermal and the mechanical analysis. The thermal quantities are evaluated using a new iterative scheme that properly accounts for con...

The paper deals with analysis, modelling and simulation of complex route systems. Presented methodology and mathematical modelling methods explain how ascending and descending road slopes influence energy management in the power-train of hybrid or electric vehicles. Advantages of the proposed route model over speed profiles that are commonly used i...

In this paper the influence of torsional warping of cross-sections of twisted beams on their eigenvibrations is investigated, considering the secondary deformations due to the angle of twist. The investigation is based on the analogy of second-order bending beam theory, including the effect of the deformations due to the shear forces on the deforma...

In this paper the influence of torsional warping of cross-sections of twisted beams on their eigenvibra-tions is investigated, considering the secondary deformations due to the angle of twist. The investigation is based on the analogy of second-order bending beam theory, including the effect of the deformations due to the shear forces on the deform...

span lang="EN-GB">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 (R...

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 transver...

This paper presents the methodology for determining the electrical resistance of polygonal pole for high voltage electric power lines. Icosahedral pole was considered where its total electrical resistance is combination of the electrical resistances of the pole's material and the resistance of the slipping contacts between different pole's parts. M...

Actuator is a mechatronic system that transforms one type of energy (e.g. electric energy) into the mechanical displacement and mechanical force (mechanical energy). Nowadays, these actuators can be made of Functionally Graded Materials (FGM) to ensure simple shape of the actuator and to improve its effectiveness, particularly for micro systems. FG...

The paper deals with electro-thermal and structural analysis, modeling and simulation of the Shape Memory Alloy (SMA) actuator made of Nickel-Titanium alloy. Primary goal is focused on electro-thermal analysis and investigation of SMA actuator temperature distribution near mechanical connection. The secondary goal is focused on actuation deformatio...

Core-shell nanowires are promising building elements of solar cells for advanced solar energy conversion. They are inexpensive since of the small amount of material needed and are efficient because of strong light absorption and rapid carrier collection. In this paper, we discuss the deposition of ZnO thin films on GaP substrate and GaP nanowires b...

Structures made of Functionally Graded Materials (FGMs) show a gradual variation of material properties in one, two, or three directions. In this paper, an efficient low‐order shell element with six nodal degrees of freedom (including the drill rotation) is presented, supplemented with a proper method for calculating effective elastic properties. T...

In this paper we discuss the derivation of quadrilateral shell elements with drilling degrees of freedom. Those in-plane rotational degrees of freedom are included within the membrane part using a recently proposed functional. This functional is based on pure mechanical considerations since the Cosserat continuum is used as an initial point. The re...

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 eigenfre...

In this contribution, new electro-thermal link finite element for Functionally Graded Materials (FGM) will be presented. Spatial variation of material properties as well as varying convection effect will be considered. FEM equations describing the behaviour of the link element will be based on semi-analytical calculation of ordinary differential eq...

A differential equation of the homogenized functionally graded material (FGM) beam deflection and its solution will be presented which has been used in free vibration analysis of the beams with polynomial continuous longitudinal and transversal variation of material properties. The FGM beams are considered to be resting on longitudinal variable (Wi...

In the proposed contribution the effect of the shear correction function is originally studied and evaluated in modal analysis of the functionally graded material (FGM) beams. Spatially continuous variations of the material properties are considered. The shear correction function is calculated from the shear strain energy equation including spatial...

New 3D beam finite element including non-uniform torsion will be presented in this contribution which is suitable for analysis of beam structures of open and closed cross-sections. The secondary torsion moment deformation effect will be included into the stiffness matrix. Results of the numerical experiments will be discussed and evaluated. (C) 201...

The paper examines the modeling and simulation of piezoelectric MEMS pressure sensor which is AlGaN/GaN based circular high electron mobility transistor (C-HEMT) structure. The influence of the residual stress plays an important role in correct modeling of MEMS piezoelectric pressure sensor. Residual stresses which were measured by micro-Raman spec...

In this contribution we deal with calculation of a free vibration of the 2-D functionally graded material (FGM) beam with continuous spatial variation of material properties. The fourth-order differential equation of the second order beam theory has been used, which was presented in our previous works. The continuous variation of the effective elas...

The subject of the present paper is an innovative approach to the investigation of the non-uniform torsional behaviour of prismatic beams taking into account the secondary torsional moment deformation effects. This investigation contains computational and experimental parts for both open and closed thin-walled crosssections. Results of original exp...