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Number of results: 133
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Abstract

Laplace Transform is often used in solving the free vibration problems of structural beams. In existing research, there are two types of simplified models of continuous beam placement. The first is to regard the continuous beam as a single-span beam, the middle bearing of which is replaced by the bearing reaction force; the second is to divide the continuous beam into several simply supported beams, with the bending moment of the continuous beam at the middle bearing considered as the external force. Research shows that the second simplified model is incorrect, and the frequency equation derived from the first simplified model contains multiple expressions which might not be equivalent to each other. This paper specifies the application method of Laplace Transform in solving the free vibration problems of continuous beams, having great significance in the proper use of the transform method.

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Authors and Affiliations

H.B. Wen
T. Zeng
G.Z. Hu
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Abstract

A system for precise angular laser beam deflection by using a plane mirror is presented. The mirror was fixed to two supports attached to its edges. This article details the theoretical basis of how this deflector works. The spring deflection of a flat circular metal plate under a uniform axial buckling was used and the mechanical stress was generated by a piezoelectric layer. The characteristics of the deformation of the plate versus the voltage control of the piezoelectrics were examined and the value of the change resolution possible to obtain was estimated. An experimental system is presented and an experiment performed to examine this system. As a result, a resolution of displacement of 10-8 rad and a range of 10-5 rad were obtained.

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Authors and Affiliations

Olga Iwasińska-Kowalska
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Abstract

The vibration and stability analysis of uniform beams supported on two-parameter elastic foundation are performed. The second foundation parameter is a function of the total rotation of the beam. The effects of axial force, foundation stiffness parameters, transverse shear deformation and rotatory inertia are incorporated into the accurate vibration analysis. The work shows very important question of relationships between the parameters describing the beam vibration, the compressive force and the foundation parameters. For the free supported beam, the exact formulas for the natural vibration frequencies, the critical forces and the formula defining the relationship between the vibration frequency and the compressive forces are derived. For other conditions of the beam support conditional equations were received. These equations determine the dependence of the frequency of vibration of the compressive force for the assumed parameters of elastic foundation and the slenderness of the beam.

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Authors and Affiliations

P. Obara
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Abstract

Assessment of the flexural buckling resistance of bisymmetrical I-section beam-columns using FEM is widely discussed in the paper with regard to their imperfect model. The concept of equivalent geometric imperfections is applied in compliance with the so-called Eurocode’s general method. Various imperfection profiles are considered. The global effect of imperfections on the real compression members behaviour is illustrated by the comparison of imperfect beam-columns resistance and the resistance of their perfect counterparts. Numerous FEM simulations with regard to the stability behaviour of laterally and torsionally restrained steel structural elements of hot-rolled wide flange HEB section subjected to both compression and bending about the major or minor principal axes were performed. Geometrically and materially nonlinear analyses, GMNA for perfect structural elements and GMNIA for imperfect ones, preceded by LBA for the initial curvature evaluation of imperfect member configuration prior to loading were carried out. Numerical modelling and simulations were conducted with use of ABAQUS/Standard program. FEM results are compared with those obtained using the Eurocode’s interaction criteria of Method 1 and 2. Concluding remarks with regard to a necessity of equivalent imperfection profiles inclusion in modelling of the in-plane resistance of compression members are presented.

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Authors and Affiliations

M.A. Giżejowski
R.B. Szczerba
M.D. Gajewski
Z. Stachura
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Abstract

This paper presents the beam tracing with refraction method, developed to examine the possibility of creating the beam tracing simulation of sound propagation in environments with piecewise non- homogenous media. The beam tracing with refraction method (BTR) is developed as an adaptive beam tracing method that simulates not only the reflection but also the refraction of sound. The scattering and the diffraction of sound are not simulated. The BTR employs 2D and 3D topology in order to efficiently simulate scenes containing non-convex media. After the beam tracing is done all beams are stored in a beam tree and kept in the computer memory. The level of sound intensity at the beginning of each beam is also memorized. This beam data structure enables fast recalculation of results for stationary source and geometry. The BTR was compared with two commercial ray tracing simulations, to check the speed of BTR algorithms. This comparison demonstrated that the BTR has a performance similar to state-of- the-art room-acoustics simulations. To check the ability to simulate refraction, the BTR was compared with a commercial Finite Elements Method (FEM) simulation. In this comparison the BTR simulated the focusing of the ultrasound with an acoustic lens, with good accuracy and excellent performance.

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Authors and Affiliations

Marjan Sikora
Ivo Mateljan
Nikola Bogunović
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Abstract

In this paper, a comprehensive study is carried out on the dynamic behaviour of Euler–Bernoulli and Timoshenko beams resting on Winkler type variable elastic foundation. The material properties of the beam and the stiffness of the foundation are considered to be varying along the length direction. The free vibration problem is formulated using Rayleigh-Ritz method and Hamilton’s principle is applied to generate the governing equations. The results are presented as non-dimensional natural frequencies for different material gradation models and different foundation stiffness variation models. Two distinct boundary conditions viz., clamped-clamped and simply supported-simply supported are considered in the analysis. The results are validated with existing literature and excellent agreement is observed between the results.

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Bibliography


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[21] B. Karami and M. Janghorban. A new size-dependent shear deformation theory for free vibration analysis of functionally graded/anisotropic nanobeams. Thin-Walled Structures, 143:106227, 2019. doi: 10.1016/j.tws.2019.106227.
[22] I. Esen. Dynamic response of a functionally graded Timoshenko beam on two-parameter elastic foundations due to a variable velocity moving mass. International Journal of Mechanical Sciences, 153–154:21–35, 2019. doi: 10.1016/j.ijmecsci.2019.01.033.
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Authors and Affiliations

Saurabh Kumar
1

  1. Department of Mechanical Engineering, School of Engineering, University of Petroleum andEnergy Studies (UPES), Dehradun, 248007, India.
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Abstract

A method of calculating the deflections of steel plate-concrete composite beams is proposed. In the hybrid work of such beams the properties of reinforced concrete and composite structures are combined. This convention should be followed in considering their ultimate capacity and serviceability limit state. The proposed solution has been verified in experimental studies performed by the authors. Good compatibility of theoretical calculations and experimental results has been obtained. It allows the theoretical solution to be used in the analysis of other cases with parameters different than those of the discussed beams. In the experiments done by the author six beams of total length of 5.20 m and theoretical length of 5,00 m were used. The cross section was rectangular, 0.24 m in width and 0.49 m in height. The steel plate 4.74 m long was 6.10 and 16 mm thick. The diameter of the flexible connectors was 13 mm. Their spacing varied between 80 and 200 mm. Owing to the flexibility of the connectors the interface slip between the steel and concrete parts was included in the theoretical solutions. The results of an in-depth analysis indicate that the deflections of steel plate-concrete composite beams are affected by the compressive strength of concrete and the yield point of steel as well as connectors’ diameter and spacing. This impact varies, that of the yield point of the steel from which the plate is made being the highest.
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Authors and Affiliations

Dawid Kisała
1
Kazimierz Furtak
1
ORCID: ORCID

  1. Department of Bridge and Tunnel Building, Tadeusz Kościuszko Cracow University of Technology, Warszawska 24 St., 31-155 Kraków, Poland
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Abstract

This study focuses to develop a new hybrid Engineered Cementitious Composite (ECC) and assesses the performance of a new hybrid ECC based on the steel short random fiber reinforcement. This hybrid ECC aims to improve the tensile strength of cementitious material and enhance better flexural performance in an RC beam. In this study, four different mixes have been investigated. ECC with Poly Vinyl Alcohol (PVA) fiber and PolyPropylene (PP) fiber of 2.0% volume fraction are the two Mono fiber mixes; ECC mix with PVA fiber of 0.65% volume fraction hybridized with steel fiber of 1.35% volume fraction, PP fiber of 0.65% volume fraction hybridized with steel of 1.35% volume fraction are the two additional different hybrid mixes. The material properties of mono fiber ECC with 2.0 % of PVA is kept as the reference mix in this study. The hybridization with fibers has a notable achievement on the uniaxial tensile strength, compressive strength, Young’s modulus, and flexural behavior in ECC layered RC beams. From the results, it has been observed that the mix with PVA fiber of 0.65% volume fraction hybrid with steel fiber of 1.35% volume fraction exhibitimprovements in tensile strength, flexural strength, andenergy absorption. ThePP fiber of 0.65% volume fraction hybridized with steel of 1.35% volume fraction mix has reasonable flexural performance and notable achievement in displacement ductility overthe reference mix.

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Authors and Affiliations

A.R. Krishnaraja
Dr.S. Kandasamy
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Abstract

In the paper, the method of a numerical simulation concerning diagonal crack propagation in con-crete beams was presented. Two beams reinforced longitudinally but without shear reinforcement were considered during the Finite Element Method analysis. In particular, a nonlinear method was used to simulate the crack evaluation in the beams. The analysis was performed using the commercial program ANSYS. In the numerical simulation, the limit surface for concrete described by Willam and Warnke was applied to model the failure of concrete. To solve the FEM-system of equations, the Newton-Raphson method was used. As the results of FEM calculations, the trajectories of total stains and numerical images of smeared cracks were obtained for two analyzed beams: the slender beam S5 of leff = 1.8 m and the short beam S3k of leff = 1.1 m. The applied method allowed to generate both flexural vertical cracks and diagonal cracks in the shear regions. Some differences in the evaluation of crack patterns in the beams were observed. The greater number of flexural vertical cracks which penetrated deeper in the beam S5 caused the lower stiffness and the greater deformation in the beam S5 compared to the short beam S3k. Numerical results were compared with the experimental data from the early tests performed by Słowik [3]. The numerical simulation yielded very similar results as the experiments and it confirmed that the character of failure process altered according to the effective length of the member. The proposed numerical procedure was successfully verified and it can be suitable for numerical analyses of diagonal crack propagation in concrete beams.

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Authors and Affiliations

M. Słowik
P. Smarzewski
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Abstract

The paper describes the dynamics of a composite cantilever beam with an active element. The vibrations of the kinematically excited beam are controlled with the use of a Macro Fiber Composite actuator. A proportional control algorithm is considered. During the analysis, actuator is powered by a time-varying voltage signal that is changed proportionally to the beam deflection. The MFC element control system with the implemented algorithm allowed for changing the stiffness of the tested structure. This is confirmed by the numerical and experimental results. Resonance curves for the beam with and without control are determined. The results show a very good agreement in qualitative terms.

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Bibliography

[1] R.B.Williams, G. Park, D.J. Inman, and W.K.Wilkie. An overview of composite actuators with piezoceramic fibers. In: Proceedings of 20th International Modal Analysis Conference, Los Angeles, CA, 4–7 February, 2002, SPIE – The International Society for Optical Engineering, 4753:421–427, 2002.
[2] B.W. Lacroix. On the mechanics, computational modeling and design implementation of piezoelectric actuators on micro air vehicles. Ph.D. Thesis, University of Florida, Gainesville, USA, 2013.
[3] T.A. Probst. Evaluating the Aerodynamic Performance of MFC-Actuated Morphing Wings to Control a Small UAV. Masters Thesis, Virginia Polytechnic Institute and State University, Blacksburg, USA, 2012.
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Authors and Affiliations

Jarosław Gawryluk
1
Andrzej Mitura
1
Andrzej Teter
1

  1. Department of Applied Mechanics, Mechanical Engineering Faculty, Lublin University of Technology, Lublin, Poland.
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Abstract

In the paper, the authors discuss the possibility to apply the "Nodalised Beam" method for vibroinsulation of manually operated tools. They indicate the difficulties in applying the original method for this purpose. On the bases of the reciprocity principle, the authors propose a method for modifying the system that allows them to avoid the mentioned disadvantages. Equations derived for the modified system that makes it possible to define the position of nodal points. The relations were verified at a test station. Furthermore, a method of tuning the system was proposed.
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Authors and Affiliations

Leszek Majkut
Jerzy Michalczyk
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Abstract

The paper presents a study of a possible application of structure embedded piezoelectric actuators to enhance the performance of a rotating composite beam exhibiting the coupled flexural-flexural vibrations. The discussed transversal and lateral bending modal coupling results from the directional properties of the beam's laminate and ply stacking distribution. The mathematical model of the beam is based on an assumption of cross-sectional non-deformability and it incorporates a number of non-classical effects. The final 1-D governing equations of an active composite beam include both orthotropic properties of the laminate and transversely isotropic properties of piezoelectric layers. The system's control capabilities resulting from embedded Macro Fiber Composite piezoelectric actuators are represented by the boundary bending moment. To enhance the dynamic properties of the composite specimen under consideration a combination of linear proportional control strategies has been used. Comparison studies have been performed, including the impact on modal coupling magnitude and cross-over frequency shift.
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Authors and Affiliations

Marcin Bocheński
Jarosław Latalski
Jerzy Warmiński
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Abstract

In this work, transient and free vibration analyses are illustrated for a functionally graded Timoshenko beam (FGM) using finite element method. The governing equilibrium equations and boundary conditions (B-Cs) are derived according to the principle of Hamilton. The materials constituents of the FG beam that vary smoothly along the thickness of the beam (along beam thickness) are evaluated using the rule of mixture method. Power law index, slenderness ratio, modulus of elasticity ratio, and boundary conditions effect of the cantilever and simply supported beams on the dynamic response of the beam are studied. Moreover, the influence of mass distribution and continuous stiffness of the FGM beam are deeply investigated. Comparisons between the current free vibration results (fundamental frequency) and other available studies are performed to check the formulation of the current mathematical model. Good results have been obtained. A significant effect is noticed in the transient response of both simply supported and cantilever beams at the smaller values of the power index and the modulus elasticity ratio.

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Bibliography

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[19] A. Doroushi, M.R. Eslami, and A. Komeili. Vibration analysis and transient response of an FGPM beam under thermo-electro-mechanical loads using higher-order shear deformation theory. Journal of Intelligent Material Systems and Structures, 22(3):231–243, 2011. doi: 10.1177/1045389X11398162.
[20] M.J. Aubad, S.O.W. Khafaji, M.T. Hussein, and M.A. Al-Shujairi. Modal analysis and transient response of axially functionally graded (AFG) beam using finite element method. Materials Research Express, 6(10):1065g4, 2019. doi: 10.1088/2053-1591/ab4234.
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Authors and Affiliations

Salwan Obaid Waheed Khafaji
1
Mohammed A. Al-Shujairi
1
Mohammed Jawad Aubad
1

  1. Department of Mechanical Engineering, Faculty of Engineering, University of Babylon, BabylonProvince, Iraq.
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Abstract

Operation of an electrically controlled beam steering device based on Rochon prism made by use of nematic liquid crystal is modelled numerically. Deflection angles and angular distribution of light intensity in the deflected beam are calculated. Dynamics of the device is studied. Advantage of application of dual frequency nematic liquid crystal is demonstrated. Role of flexoelectric properties of the nematic is analyzed.

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Authors and Affiliations

M. Buczkowska
G. Derfel
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Abstract

In this work we report on fabrication of quantum wires and quantum point contacts from the modulation doped CdMgTe/Cd(Mn)Te structures, with the application of a high-resolution electron-beam lithography. We emphasize on methods which were not yet utilized for these substrate materials. In particular, we describe the so-called shallow-etching approach, which allows for the fabrication of quantum constrictions of a physical width down to 100 nm, which are characterized by the smoother confining potential as compared to the deep-etched devices. For that purpose, a single-line exposure mode of electron-beam lithography has been used. We demonstrate also, how to combine the etching of separating grooves with the thermal evaporation of metal side-gates into a single post-processing stage of a quantum point contact fabrication.

This article is an expanded version of the scientific reports presented at the International Conference on Semiconductor Nanostructures for Optoelectronics and Biosensors 2016 ICSeNOB2016, May 22–25, 2016, Rzeszow, Poland.

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Authors and Affiliations

Joanna Wróbel
E. Bobko
Dariusz Płoch
ORCID: ORCID
M. Wiater
T. Wojtowicz
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Abstract

The paper presents the results of tests on dynamic stability of Bernoulli-Euler beam with damages. Damages (cracks) were modeled using three rotational springs. An analysis of the influence of crack depth and their position relative to the beam ends on dynamic stability of the beam was carried out. The problem of dynamic stability was solved by applying the mode summation method. Applying an orthogonal condition of eigenfunctions, the dynamic of the system was described with the use of the Mathieu equation. The obtained equation allowed the dynamic stability of the tested system to be analyzed. Stable and unstable solutions were analyzed using the Strutt card.
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Authors and Affiliations

W. Sochacki
1
ORCID: ORCID
S. Garus
1
ORCID: ORCID
J. Garus
1
ORCID: ORCID

  1. Czestochowa University of Technology, Department of Mechanics and Fundamentals of Machinery Design, Faculty of Mechanical Engineering and Computer Science, 73 Dąbrowskiego Str., 42-201 Częstochowa, Poland
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Abstract

The presented results are for the numerical verification of a method devised to identify an unknown spatio-temporal distribution of heat flux that occurs at the surface of a thin aluminum plate, as a result of pulsed laser beam excitation. The presented identification of boundary heat flux function is a part of the newly proposed laser beam profiling method and utilizes artificial neural networks trained on temperature distributions generated with the ANSYS Fluent solver. The paper focuses on the selection of the most effective neural network hyperparameters and compares the results of neural network identification with the Levenberg–Marquardt method used earlier and discussed in previous articles. For the levels of noise measured in physical experiments (0.25–0.5 K), the accuracy of the current parameter estimation method is between 5 and 10%. Design changes that may increase its accuracy are thoroughly discussed.
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Authors and Affiliations

Karol Pietrak
1
ORCID: ORCID
Radosław Muszyński
1
Adam Marek
1
Piotr Łapka
1
ORCID: ORCID

  1. Faculty of Power and Aeronautical Engineering, Warsaw University of Technology, ul. Nowowiejska 24, 00-665 Warsaw, Poland
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Abstract

The main aim of the study is an assessment of models suitability for steel beams made of thin-walled cold-formed sigma profiles with respect to different numerical descriptions used in buckling analysis. The analyses are carried out for the sigma profile beam with the height of 140 mm and the span of 2.20 m. The Finite Element (FE) numerical models are developed in the Abaqus program. The boundary conditions are introduced in the formof the so-called fork support with the use of displacement limitations. The beams are discretized using S4R shell finite elements with S4R linear and S8R quadratic shape functions. Local and global instability behaviour is investigated using linear buckling analysis and the models are verified by the comparison with theoretical critical bending moment obtained from the analytical formulae based on the Vlasow beam theory of the thin-walled elements. In addition, the engineering analysis of buckling is carried out for a simple shell (plate) model of the separated cross-section flange wall using the Boundary Element Method (BEM). Special attention was paid to critical bending moment calculated on the basis of the Vlasov beam theory, which does not take into account the loss of local stability or contour deformation. Numerical shell FE models are investigated, which enable a multimodal buckling analysis taking into account interactive buckling. The eigenvalues and shape of first three buckling modes for selected numerical models are calculated but the values of critical bending moments are identified basing on the eigenvalue obtained for the first buckling mode.
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Authors and Affiliations

Katarzyna Rzeszut
1
ORCID: ORCID
Ilona Szewczak
2
ORCID: ORCID
Patryk Różyło
3
ORCID: ORCID
Michał Guminiak
4
ORCID: ORCID

  1. Poznan University of Technology, Institute of Building Engineering, Marii Skłodowskiej-Curie 5, 60-965 Poznan
  2. Lublin University of Technology, Faculty of Civil Engineering and Architecture, ul. Nadbystrzycka 38D,20–618 Lublin, Poland
  3. Lublin University of Technology, Faculty of Mechanical Engineering, ul. Nadbystrzycka 38 D, 20–618 Lublin, Poland
  4. Poznan University of Technology, Institute of Structural Analysis, Marii Skłodowskiej-Curie 5, 60-965 Poznan, Poland
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Abstract

In the present paper tensile stresses perpendicular to the grain in reinforced double-tapered beams made of glued laminated timber are discussed. The beams are analysed using the finite element method within the linear elasticity theory with the influence of orthotropic material properties. The main objective is to assess the influence of transverse reinforcement on the values and distributions of the analysed stresses and to identify the most efficient scheme of reinforcement. The obtained results prove that, with the use of the proposed tools, it is possible to assess the level of stress, including delaminating stress, and to indicate the areas of occurrence of such stress with high precision.

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Authors and Affiliations

A. Al Sabouni-Zawadzka
W. Gilewski
J. Pełczyński
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Abstract

Double-beam model is considered in many investigations both theoretical and typically engineering ones. One can find different studies concerning analysis of such structures behaviour, especially in the cases where the system is subjected to dynamic excitations. This kind of model is successfully considered as a reliable representation of railway track. Inclusion of nonlinear physical and geometrical properties of rail track components has been justified by various computational studies and theoretical analyses. In order to properly describe behaviour of real structures their nonlinear properties cannot be omitted. Therefore a necessity to search appropriate analytical nonlinear models is recognized and highlighted in published literature. This paper presents essential extension of previously carried out double-beam system analysis. Two nonlinear factors are taken into account and parametrical analysis of the semi-analytical solution is undertaken with special emphasis on different range of parameters describing nonlinear stiffness of foundation and layer between beams. This study is extended by preliminary discussion regarding the dynamic effects produced by a series of loads moving along the upper beam. A new solution for the case of several forces acting on the upper beam with different frequencies of their variations in time is presented and briefly discussed.
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Authors and Affiliations

Piotr Koziol
1
ORCID: ORCID
Rafał Pilecki
2
ORCID: ORCID

  1. PhD, DSc, Assoc. Prof., Cracow University of Technology, Faculty of Civil Engineering, ul. Warszawska 24, 31-155 Kraków, Poland
  2. MSc, Eng., former student of Cracow University of Technology
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Abstract

The paper discusses the problem of the accuracy of the identification techniques detecting cracks and corroded members in vibrating beam and frame structures. The presence of the fatigue crack usually causes very small changes of the stiffness of the beam elements of the structure. To detect these changes it is necessary to apply the most precisely mathematical detection technique. The identification procedure based on the least squares technique uses finite element models (FEM) of the structure and as the source of information the measured dynamic response and the natural frequencies. The application of the Dynamic Stiffness Matrix (DSM) [I) for the representation of all constraints and modal equations makes it possible to present the identification process in a very accurate and efficient mathematical form. The methoyof d of the detection of structural changes used in the present paper was described in our previous paper (2). The Consistent Mass Matrices (CMM) and Lump Mass Matrices (LMM) are very often used in the identification algorithms. It is shown that application of simplified approaches (CMM and LMM) can result in lower accuracy and poorer convergence of the identification algorithms. However, the application ofCMM mass matrices does not introduce significant errors. The algorithms were tested on simulated numerical data for ten element beam frames.
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Authors and Affiliations

Stanisław A. Lukasiewicz
Emily R. Qian
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Abstract

The paper presents the effect of electron beam alloying on the surface of a copper flat bar (M1Ez4) with titanium powder. Due to the quality of the surface after alloying and the obtained properties, the parameters used were given which met the assumed conditions to the greatest extent. The microstructure and mechanical properties as well as the chemical composition of surface-modified electron-beam copper show improved mechanical properties, i.e. hardness and abrasion resistance. This article uses research techniques using scanning electron microscopy and analysis of chemical composition in micro-areas (EDS). In order to examine the properties of the material after electron beam modification, hardness measurements were performed at low loads (HV0.1), abrasion resistance was tested, and conductivity was also measured. As a result of modifying the chemical and phase composition of M1E copper using an electron beam, the hardness increased by 46%, while the conductivity decreased by 16% due to the formation of intermetallic phases during solidification.
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Bibliography

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Authors and Affiliations

P.E. Smolarczyk
1
ORCID: ORCID
M. Krupiński
1
ORCID: ORCID
M. Węglowski
2
ORCID: ORCID
Wojciech Pakieła
1
ORCID: ORCID
P. Śliwiński
2
ORCID: ORCID

  1. Department of Engineering Materials and Biomaterials, Silesian University of Technology, Konarskiego 18A, 44-100 Gliwice, Poland
  2. Łukasiewicz Research Network – Upper Silesian Institute of Technology, Bł. Czesława 16-18, 44-100 Gliwice, Poland
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Abstract

In this paper an alternative procedure to vibro-acoustics study of beam-type structures is presented. With this procedure, it is possible to determine the resonant modes, the bending wave propagation velocity through the study of the radiated acoustic field and their temporal evolution in the frequency range selected. As regards the purely experimental aspect, it is worth noting that the exciter device is an actuator similar to is the one employed in distributed modes loudspeakers; the test signal used is a pseudo random sequence, in particular, an MLS (Maximum Length Sequence), facilitates post processing. The study case was applied to two beam-type structures made of a sandstone material called Bateig. The experimental results of the modal response and the bending propagation velocity are compared with well-established analytical solution: Euler-Bernoulli and Timoshenko models, and numerical models: Finite Element Method – FEM, showing a good agreement.
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Authors and Affiliations

Jeniffer Torres-Romero
William Cardenas
Jesus Carbajo
Segovia Eulogio Enrique G.
Ramis-Soriano Jaime
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Abstract

By the method of modern physical material science (optic microscopy scanning and transmission electron microscopy) the analysis of structural phase states, the morphology of the second phase inclusions and defect substructure of Al-Si alloy (silumin) of hypoeutectic composition, subjected to electron beam processing was done with the following parameters: energy density 25-35 J/cm2, beam length 150 μs, pulse number – 3, pulse repetition rate – 0.3 Hz, pressure of residual gas (argon) 0.02 Pa. The surface irradiation results in the melting of the surface layer, the dissolution of boundary inclusions, the stricture formation of high speed cellular crystallization of submicron sizes, the repeated precipitation of the second phase nanodimentional particles. With the increased distance from the irradiation surface the layer containing the second phase inclusions of quasi-equilibrium shape along with the crystallization cells was revealed. It is indicative of the processes of Al-Si alloy structure globalization on electron beam processing.

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Authors and Affiliations

S. Konovalov
V. Gromov
D. Zaguliyaev
Y. Ivanov
A. Semin
J. Rubannikova

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