Program rada seminara Nonlinear dynamics - Milutin Milankovic
Gost Projekta ON144002 i seminara Nonlinear Dynamics prog. dr E.E. Gdoutos održaće predavanje u Sredu, 11. novembara 2009. u sali 2 na prvom spratu zgrade SANU, u Beogradu , ul. Knez Mihailova 35, u 18:00 časova Sreda, 11. novembar 2009.
E.E. Gdoutos Office of Theoretical and Applied Mechanics of the Academy of Athens School of Engineering, Democritus University of Thrace, GR-671 00 Xanthi, Greece E-mail: egdoutos@civil.duth.gr
FAILURE MECHANISMS OF COMPOSITE SANDWICH STRUCTURES Sandwich panels consist typically of two thin face sheets (or facings, or skins) and a lightweight thicker core. They display various failure modes under general bending, shear and in-plane loading. The failure modes can be predicted by conducting a thorough stress analysis and applying appropriate failure criteria in the critical regions of the beams. The analysis is difficult because of the nonlinear and inelastic behavior of the constituent materials and the complex interactions of failure modes. A thorough investigation of the failure mechanisms of composite sandwich beams under four- and three-point bending and cantilever beams was undertaken. The beams were made of unidirectional carbon/epoxy (AS4/3501-6) facings and a PVC closed-cell foam (Divinycell) core. Two types of core material H100 and H250 with densities 100 and 250 kg/m3, respectively, were used. The thickness of the facings and core were 1 mm and 25.4 mm, respectively. Sandwich beams were loaded under bending moment and shear and failure modes were observed and compared with analytical predictions. The failure modes investigated are face sheet compressive failure, core failure, facing wrinkling and indentation failure. The various modes have been studied separately and both initiation and ultimate failure have been determined. Initiation of a particular failure mode and triggering and interaction with other failure modes was also investigated. A detailed stress and failure analysis was performed taking into account that a biaxial state of stress is developed in both the core and the facings. The stress state was combined with the Tsai-Wu failure criterion for both the core and the facings. A failure map for the entire specimen was constructed. Failure in the core occurs in the form of crack initiation. The crack initiation was predicted and compared with experimental observations The initiation of the various failure modes depends on the material properties of the constituents (facings, adhesive, core), geometric dimensions and type of loading. The appropriate failure criteria should account for the complete state of stress at a point, including two- and three-dimensional effects. Failure modes were discussed according to the type of loading applied. In sandwich columns under compression, or beams in pure bending, compressive failure of the skins takes place if the core is sufficiently stiff in the through-the-thickness direction. Otherwise, facing wrinkling takes place, which can be predicted by Heath’s formula. In the case of beams subjected to bending and shear the type of failure initiation depends on the relative magnitude of the shear component. When the shear component is low (long beams), facing wrinkling occurs first while the core is still in the linear elastic range. The critical stress at wrinkling can be predicted satisfactorily by an expression by Hoff and Mautner and depends only on the facing and core moduli. When the shear component is relatively high (e.g., short beams), core shear failure takes place first and is followed by compression facing wrinkling. Wrinkling failure follows but at a lower than predicted critical stress. The predictive expression must be adjusted to account for the reduced core moduli.
Matematički institut SANU u Beogradu - Projekat ON144002 i Centar za nelinearnu dinamiku i aktivne konstrukcije Mašinskog fakulteta u Nišu
Program rada za novembar 2009 Seminara Nonlinear dynamics - Milutin Milanković
Rukovodilac projekta ON144002 Vas poziva da prisustvujete usmenoj javnoj odbrani doktorske disertacije mr Dragana Jovanovića i usmenoj javnoj odbrani magistarske teze Srdjana Jocića istraživača na Projektu ON144002
Utorak, 10. novembar 2009. u 11,00 h na Mašinskom fakultetu u Nišu, u svečanoj sali 401.
Mr Dragan B. Jovanović, istraživač na projektu ON144002 Usmena javna odbrana doktorske disertacije pod nazivom:
POTENCIJALNA ENERGIJA I STANJE NAPONA U MATERIJALU SA PRSLINOM
Komisija za odbranu Prof, dr Katica R. (Stevanović) Hedrih, Matematički institut SANU Beograd Prof. dr Emanuel E. Gdoutos, Northwestern University, Illinois, USA Democritus University of Trace, Xanthi, Greece Prof. dr Stevan Maksimović, naučni savetnik Vojno-tehničkog institta Vojske Srbije Prof. dr Predrag Kozić, Mašinski fakultet Univerziteta u Nišu dr Mile Maksić, vanr. prof., Mašinski fakultet Univerziteta u Nišu
Petak, 6. novembar 2009, u 11,00 h na Fakultetu tehničkih nauka u Kosovskoj Mitrovici, Univerziteta u Prištini Srdjan Jović, istraživač na projektu ON144002 Usmena javna odbrana magistarske teze pod nazivom:
ENERGIJSKA ANALIZA DINAMIKE VIBROUDARNIH SISTEMA
Komisija za odbranu Prof, dr Katica R. (Stevanović) Hedrih, Matematički institut SANU Beograd Prof. dr Vladimir Raičević, Fakultet tehničkih nauka, Kosovska Mitrovica, Univerzitet u Prištini Prof. dr Zlatibor Vasić, Fakultet tehničkih nauka Kosovska Mitrovica, Univerzitet u Prištini
Pozivaju se istrazivači sa Projekta ON144002, studentu, saradnici i nastavnici da prisustvuju odbranama.. Posebno se poziv upućuje studentima doktorskih studija da prisustvuju predavanjima.
Rukovodilac seminara i Projekta ON144002. Katica R. (Stevanović) Hedrih , Matematički institut SANU Beograd
----------- Matematicki institut SANU u Beogradu - Projekat ON144002 i Centar za nelinearnu dinamiku i aktivne konstrukcije Masinskog fakulteta u Nisu
Program rada Seminara Nonlinear dynamics - Milutin Milankovic za oktobar 2009
Rukovodilac projekta ON144002 ce odrzati seriju predavanja na temu DINAMIKA SISTEMA
Cetvrtak, 8. oktovar 2009. u 11,00 h na Masinskom fakultetu u Nisu, u svecanoj sali 401.
Katica R. (Stevanovic) Hedrih Vibrations, Energy and Powers of Force Works of a Material Particle Motion along Rough Line with Friction of Coulomb Type
Vibrations, mechanical energies, constraint reactions and powers of reactive forces of a heavy material particle motion along rough curvilinear line with friction Coulomb type are considered. Mathematical decryption of the heavy material particle motion along rough curvelinear line with friction in generalized form is presented in a natural coordinate system of the corresponding line. A special case of a rough line with friction presented in this paper are a rough circle and a rough cycloid. . These cases of a heavy material particle motion along rough curvilinear lines, in vertical plane, are considered in the phase plane and analytical expressions for the phase trajectories are obtained with corresponding initial conditions and corresponding kinetic state of the alternations of the force of Coulomb type friction. Analytical expressions of kinetic, potential and total energies of the material particle motion, as well as analytical expressions of the Coulomb type friction force and for power of this force are obtained.
Cetvrtak, 15. oktobar 2009, u 11,00 h na Masinskom fakultetu u Nisu, u svecanoj sali 401.
Katica R. (Stevanovic) Hedrih Vibro-impact system dynamics: Heavy material particle oscillations along rough circle with radial two side impact limiter of the elongations
Paper present analytical results and some visualizations of the nonlinear dynamics of vibro-impact system with one degree of freedom and radial two side impact limiter of the elongations. Lecturer plan to present common results of the research group of the Project ON144002 supported by Ministry of Sciences Republic of Serbia. These results are presented in the series of published papers and in the program of the international conference as well as European conferences (ESMC Lisbon 2009, ISUMEL Lvov 2009, DyVis Mosco 2009, DSTA Lodz 2009, IFAC Multiconference Ohrid 2009, SICON Roma 2009) or accepted for publishing. (China 2009, Ancara 2009, Moscow 2009…).
Cetvrtak, 22, oktobar 2009. u 11,00 h na Masinskom fakultetu u Nisu, u svecanoj sali 401.
Katica R. (Stevanovic) Hedrih Considering Transfer of Signals through Hybrid Fractional Order Homogeneous Structure
Using a basic hybrid fractional order homogeneous structure, containing coupled homogeneous chains which material particles are interconnected by standard light fractional order elements, a transfer of the signals through discrete continuum structure is analytically considered. Applying trigonometric method and Laplase transform for solving governing system of fractional order differential equations, corresponding set of the eigen main chains as independent subsystems and corresponding main chain coordinates are identified. Eigen main chains of the multichain system are independent subsystems with independent set of the signals with eigen subset of the eigen frequencies and corresponding set of characteristic number determined by fractional order properties of the hybrid systesen. em.
Cetvrtak, 29. oktobar 2009 u 11,00 h na Masinskom fakultetu u Nisu, u svecanoj sali 401.
Katica R. (Stevanovic) Hedrih Optimal Control in Engineering systems with trigger of coupled singularities
Main idea of the phase plane method applied to the optimal control in nonlinear dynamical systems with triggers of a coupled singularities, and with one degree of freedom, is reconsidered. Lecture present a short review of the author’s previous published results containing series of the special cases of the optimal control in nonlinear dynamical systems with trigger of coupled singularities important for engineering applications. These results are published in the Springer publications as well as in the Nauchanaya knyig Moscowa.
Predavanja će se održati sa pocetkom u 11,00 h na Masinskom fakultetu u Nisu, u svecanoj sali 401. Pozivaju se studentu, saradnici i nastavnici da prisustvuju predavanjima. Posebno se poziv upucuje studentima doktorskih studija da prisustvuju predavanjima.
Rukovodilac semina i Projekta ON144002. Katica R. (Stevanovic) Hedrih
Postovani profesore, Postovani kolega,
imam cast da da Vas pozovem da ucestvujete u SVECANOM OTVARANJU i radu jednodnevnog naucnog skupa Projekta ON144002 , Seminara Nonlinear Dynamics - Milutin Mialnkovic i Matematickog institute SANU:
U okviru skupa bice obelezen 80-ti rodjendan profesora Veljka A. Vujicica.
Prvo predavanje na skupu ce odrzati, gost Projekta ON144002, akademik Ruske akademije nauka Valery Kozlov. Medju ucesnicima naseg simpozijuma, pored istrazivaca sa projekta su i na nas poziv odazvale su se istaknuti profesori mehanike mehanike sa univerziteta u Bogradu, Novom Sadu i Nisu, kao i kolege dr Zoran Draskovic iz Zagreba i Prof. Dr. Ing. Tamara Nestorovic sa Rurh Univerziteta u Bochumu.
Molm Vas da Vasim prisustvom i naucnim diskusijama, komentarima na konkretna saopstenja i pitanjima doprinesete radu naseg naucnog skupa.
Mesto odrzavanja Matematicki institute SANU, ul Knez Mihailova 36/III, Beograd.
U prilogu je PDF fajl Programa skupa.
U ocekivanju Vaseg odziva, primite srdacne pozdrave, U Beogradu, 22. marta 2009. Rukovodilac projekta ON144002 Katica (Stevanovic) Hedrih
Mesto održavanja Simpozijuma: Matematički institut SANU, Knez Mihailova 36/3, Beodgrad - početak u 11 časova, 28. marta 2009. godine.
CENTAR ZA NELINEARNU DINAMIKU I AKTIVNE KONSTRUKCIJE MAŠINSKOG FAKULTETA U NIŠU VAS POZIVA DA UCESTVUJETE U RADU SEMINARA
Nelinearna dinamika - Milutin Milanković
U četvrtak, 26 . marta 2009. godine sa početkom u 11,00 h, u sali 401 Mašinskog fakulteta u Nišu.
Nenad T. Pavlović Nenad D. Pavlović održaće predavanje pod nazivom
Pokretljivost zglobova gipkih mehanizama
Sadržaj: Analizirana je pokretljivost pojedinačnih gipkih zglobova i integralnih gipkih mehanizama. Gipkost zglobova i pokretljivost gipkog mehanizma mogu se povećati promenom geometrije, kao i promenom materijala od koga je zglob izrađen, pa je analizirana pokretljivost tri vrste gipkih zglobova, različitih geometrijskih oblika (zglobovi u obliku štapa, u obliku filma i u obliku zareza). Razmatrana je i pokretljivost gipkih zglobova izrađenih od različitih vrsta materijala (zglobovi od plastike, zglobovi od silikona). Pokretljivost gipkih mehanizama prikazana je na primeru originalnih gipkih mehanizama za realizaciju pravolinijskog vođenja tačke, odnosno translatornog vođenja člana mehanizma.
Program rada Seminara Nonlinear dynamics - Milutin Milanković za februar 2009
Četvrtak, 26. februar 2009 u 12,00 h na Mašinskom fakultetu u Nišu, U Laboratoriji L307.
Dragan B. Jovanović Doprinosi mehanici ostećenja i loma
Savremena saznanja o stanju napona i stanju deformacija u okolini vrha prsline u napregnutom deformabilnom telu. Raspodela energije deformacije u okolini vrha prsline u napregnutom deformabilnom telu. Energijske metode, koje se primenjuju u izučavanju stanja napona i stanja deformacije u okolini vrha prsline u materijalu. Pogled na sopstvene doprinose.
Sreda, 18. februar 2009. u 18,00 h u Matematičkom institutu SANU u Beogradu (u biblioteci
Julijana D. Simonović Dinamički sistemi složenih struktura. Svojstva i fenomeni.
Na primerima sistema više spregnitih tankih kružnih ploča, slojevima raspodeljenih diskretnih lakih elemenata različitih konstitutivnih relacija, izučena je klasa svojstava dinamičkih sistema složenih struktura. Korišćene su analitičke i numeričke metode, kao i vizuelizacija oscilatornih, linearnih i nelinearnih, kao i stacionarnih i nestacionarnih dinamika i režima oscilovanja. Izveden je niz opštih kvalitativnih zaključaka o broju frekvencija po modovima oscilovanja, kao i o broju i vrsti rezonantnih skokova kod nelinearnih režima oscilovanja.
Četvrtak, 12. februar 2009, u 12,00 h na Mašinskom fakultetu u Nišu, u Laboratoriji L 307.
Katica R. (Stevanović) Hedrih „Beseda o MEHANICI, mojim profesorima, kolegama i studentima“ Nastavak besede i diskusija.
Predavanja će se održavati u biblioteci Matematičkog instituta SANU, Beograd, ul. Knez Mihailova 36, sa početkom u 18,00 h. ili na Mašinskom fakultetu u Nišu u Laboratoriji L307, ako nije drugačije naznačeno
CENTAR ZA NELINEARNU DINAMIKU I AKTIVNE KONSTRUKCIJE MAŠINSKOG FAKULTETA U NIŠU VAS POZIVA DA UCESTVUJETE U RADU SEMINARA
Nelinearna dinamika - Milutin Milankovic
U četvrtak, 5 . februara 2009. godine sa početkom u 11,00 h, u sali 401 Mašinskog fakulteta u Nišu.
Sadrzaj: Prikaz naučnih dometa savremene nelinearne mehanike, kao i publikovanih, u časopisima sa ISI liste, originalnih rezultata (predavača) iz oblasti elastodinamike, dinamike hibridnih sistema frakcionog reda, nelinearne dinamike, kaso i iz istorije mahanike, sa osvrtom na dela i podsticaje za posvećenost mehanici dobijenih od profesora.
Matematički institute SANU - Projekat ON144002 Program rada Seminara Nonlinear dynamics - Milutin Milankovic za decembar 2008
Subject: Poziv za Seminar Noninear Dynamics - Milutin Milankovic Poštovane kolege,
šaljem vam plan predavanja na seminaru Nonlinear Dznamics - Milutin Milanković u organizaciji Projekta ON144002, koordiniranog preko Matematičkog instituta SANU,za mesec decembar 2008. godine
Napominjem da je termin za sva predavanja SREDA u 18,00 h , a mesto održavanja BIBLIOTEKA Matematičkog instituta SANU, ul. Knez Mihajlova 35, BEOGRAD.
Srdačan pozdrav,
Katica (Stevanović) Hedrih
Rukovodilac projekta ON144002 i Seminara
Matematički institute SANU - Projekat ON144002 Program rada Seminara Nonlinear dynamics - Milutin Milankovic za decembar 2008
Sreda, 3. decembar 2008. u 18,00 h Katica R. (Stevanović) Hedrih MAIN CHAINS AND EIGEN MODES OF THE FRACTIONAL ORDER HYBRID MULTI PENDULUM SYSTEM DYNAMICS A survey as short introduction-review of author’s research results in area of dynamics of pendulum hybrid systems, as well as a analytical approach to the discrete material particle system dynamics containing creep elements with constitutive stress-strain relation described by fractional order derivative, are presented. First main research results presented in this manuscript are analytical expressions of the modes of three pendulum fractional order system vibrations. It is shown that two time modes (partial solutions) are pure periodical, and four time modes (particular solutions) are “creeping modes” as results of the creeping properties influence on standard light elements to the periodical pendulum mode vibrations with corresponding frequencies. By using analytical approach, for a fractional order hybrid multi pendulum system dynamics, eigen main chains, eigen modes and main coordinate are obtained. This second main and generalised result concerns the fractional order hybrid multi pendulum system dynamics.
Predavanja će se održati u Biblioteci Matematičkog institute SANU, Beograd, ul. Knez Mihailova 36, sa početkom u 18,00 h.
Sreda, 10. decembar 2008. u 18,00 h Veljko A. Vujičić MILANKOVICEV ZADATAK VERIFIKACIJE NJUTNOVOG ZAKONA GRAVITACIJE Osvrt na Milankovicev zadatak i razmisljanje sta je tog naucnika navelo da postavi takav zadatak. U susret svojoj pretpostavci predavac dopkazuje da Njutnova teorema o opstem zakonu gravitacije nije u saglasnosti sa osnovnim zakonima dinamike, tj. sa Njutnovim aksiomima. To se potvrdjuje na primerima problema dva i tri tela, kao i objavljenim radovima u domacim i stranim naucnim casopisima.
Predavanja će se održati u Biblioteci Matematičkog institute SANU, Beograd, ul. Knez Mihailova 36, sa početkom u 18,00 h.
Sreda, 17. decembar 2008. u 18,00 h Miloš M. Jovanović THE INFLUENCE OF APERTURES POSITION UPON DISTRIBUTION OF TENSION AT THE ISOTOPIC PLANE FIELD We consider numerical simulation of temporal Hydrodynamic Stability of plane 2D incompressible Poiseuille flow. The two-dimensional Navier-Stokes equations have been used and reduced to vorticity-streamfunction form. The trigonometric polynomials have been used in homogeneous direction and Chebyshev polynomials in inhomogeneous direction. The problem of boundary conditions for vorticity has been solved by using the method of capacitance matrix. The Orr-Sommerfeld equation has been solved by using Chebyshev polynomials, and the linear combination of the obtained eigenfunctions has been optimized in regard to the corresponding eigenvalue. We present here the results of simulation for the perturbations optimized in regard to the least stable eigenvalue for the Reynolds number Re=1000.
Predavanja će se održati u Biblioteci Matematičkog institute SANU, Beograd, ul. Knez Mihailova 36, sa početkom u 18,00 h. Sreda, 24. decembar 2008. u 18,00 h Mladen Radojković, Vera Nikolić, Zlatibor Vasić THE INFLUENCE OF APERTURES POSITION UPON DISTRIBUTION OF TENSION AT THE ISOTOPIC PLANE FIELD The distribution of tension, as known, is influenced not only by the load, the exploitation conditions, etc., but also by the geometric shapes of elements. Mechanical elements mostly have complex geometric shapes and they are weaken by some of the aperture shapes. The apertures at the mechanical parts, either transversal or vertical, are the sources of concentration of tension. Position of the aperture in relation to the direction of effect of external load, substantially influence on distribution of tension around the apertures as a source of concentration of tension. Therefore the aim of this study is the influence analysis of square aperture position, as a source of concentration of tension, upon distribution of tension. Only the parts of the isotopic materials exposed to the static loads have been considered during this research. In order to obtain the tension distribution results at the isotopic plane field weaken by apertures, the numerical method has been used. Taking the exact nature of the discussed problem into consideration, during this research The Finite Elements Method ( FEM ) has been chosen as one of the numerical methods.
Predavanje će se održati u Biblioteci Matematičkog institute SANU, Beograd, ul. Knez Mihailova 36, sa početkom u 18,00 h.
CENTAR ZA NELINEARNU DINAMIKU I AKTIVNE KONSTRUKCIJE MAŠINSKOG FAKULTETA U NIŠU I PROJEKAT ON-144002 VAS POZIVA DA UČESTVUJETE U RADU SEMINARA
CONTROL OF BIFURCATION, CHAOS AND BASIN INTEGRITY: THEORETICAL ISSUES AND APPLICATION
Abstract: Upon shortly addressing a systematic classification of methods for control of chaos and their applications to mechanical systems, a ~Suniversal~T technique for controlling homoclinic or heteroclinic bifurcations of a hilltop saddle as the triggering event for the onset of transient, and possibly steady, chaos is presented. It is based on optimally choosing the shape of a periodic excitation applied to the considered system.
Features of dynamic integrity of nonlinear oscillators are analyzed, by critically reviewing the definition of safe basin of attraction, the formulation of suitable integrity measures, and the construction of basin erosion profiles with a varying control parameter.
Hints are given on the practical capability of the control method to regularize fractal basin boundaries, reduce their erosion, and delay the occurrence of chaos or escape for various mechanical systems.
The effectiveness of the method as regards controlling the dynamic pull-in phenomenon in the nonlinear dynamics of an electrically actuated thermo-elastic micro-beam is specifically addressed by referring to a relevant minimal reduced-order model. Extensive numerical simulations highlight the good performances of the method also beyond theoretical expectations.
Predavanje će biti održano u zgradi SANU, Knez Mihailova 35, u sali 2 na prvom spratu.
CENTAR ZA NELINEARNUJ DINAMIKU I AKTIVNE KONSTRUKCIJE MAŠINSKOG FAKULTETA U NIŠU VAS POZIVA NA ODBRANU MAGISTARSKE TEZE
Mehanika krutog tela i Leonhard EULER Rigid body dynamics and Leonhard Euler (1707-1783)
Kratak sadržaj: Povodom 300 godina od rođenja velikana nauke švajcarskog, ruskog i nemačkog naučnika Leonhard Euler-a (1707-1783) prikazaće se biobibliografski podaci sa posebnim osvrtom na doprinose mehanici čvrstih i krutih tela, kao i mehanici fluida.
Abstract: Lecture is dedicated to 300-th anniversary to genius scientist Leonhard Euler (1707-1783) and will be presented bib bibliography with special part dedicated to Euler’s advances to the rigid and solid body mechanics as well as to fluid mechanics.
CENTAR ZA NELINEARNU DINAMIKU I AKTIVNE KONSTRUKCIJE MAŠINSKOG FAKULTETA U NIŠU I PROJEKAT ON-144002 VAS POZIVA DA UČESTVUJETE U RADU SEMINARA
U PETAK, 23. NOVIMBRA 2007. godine sa početkom u 11,00 časova u Laboratoriji za eksperimentalnu mehaniku – 307.
Academician Radu Miron Faculty of Mathematics, University “Al.I.Cuza” Iasi, Iasi, Romania UNIVERSITATEA „ALEXANDRU IOAN CUZA” FACULTATEA DE MATEMATICĂ Bulevardul Carol I, nr. 11 / 700506 – Iaşi R O M Â N I A Fax +40 232 201160 E-mail: radu.miron@uaic.ro održaće predavanje pod nazivom
Lagrangian and Finslerian Mechanics of Nonconservative Mechanical Systems
Kratak sadržaj: In this paper we extend the geometric investigation of nonconservative mechanical systems, using the associated evolution nonlinear connection. We show that the evolution nonlinear connection is uniquely determined by two compatibility conditions with the metric structure and the symplectic struc¬ture of the Lagrange space, [3]. The covariant derivative of the Lagrange metric tensor with respect to the evolution nonlinear connection is a second rank symmetric tensor, which uniquely determines the symmetric part of the connection. The difference between the symplectic structure of the Lagrange space and the almost-symplectic structure of the nonconservative mechanical system is the force tensor introduced by Klein [5], and used recently by Miron The force tensor, which is the vertical differential of the external force, uniquely determines the skew-symmetric part of the evolution nonlinear connection.
CENTAR ZA NELINEARNU DINAMIKU I AKTIVNE KONSTRUKCIJE MAŠINSKOG FAKULTETA U NIŠU I PROJEKAT ON-144002 VAS POZIVA DA UČESTVUJETE U RADU SEMINARA
The Dynamical Systems of Rheonomic Finslerian Mechanical Systems
Kratak sadržaj: In this paper it will be studied the dynamical system of a rheonomic Finslerian mechanical system, whose evolution curves are given, on the phase space TM x R , by Lagrange equations. Then one can associate to the considered mechanical system a vector field S on TM x R, which is a canonical semispray. All geometric objects of the rheonomic Finslerian mechanical system one can be derived from $S$. So we have the fundamental notion as the nonlinear connection S, the metrical N -linear connection, etc.
CENTAR ZA NELINEARNU DINAMIKU I AKTIVNE KONSTRUKCIJE MAŠINSKOG FAKULTETA U NIŠU I PROJEKAT ON-144002 VAS POZIVA DA UČESTVUJETE U RADU SEMINARA
Hibridni sistemi i hibridne dinamike: Teorija i primene Hybrid Systems and Hybrid Dynamics: Theory and Applications
Abstract: A survey as review of author’s research result in area of dynamics of coupled subsystems and coupled dynamical processes into hybrid systems are presented. The sets of two or many coupled partial as well as partial integro-differential equations, and also partial fractional differential equations of transversal vibrations of a elastically, as well as visco-elastic, and also creep connected double beam, as well as double plate systems, and also axially moving double belt system have been derived. The beam’s as well as plate’s materials, and also belt’s materials are elastic or viscoelastic or creeping and constitutive relations of stress-strain states are expressed through members with integral parts or of the fractional order derivatives.The analytical solutions of the sets of two coupled partial as well as partial integro-differential equations, and also partial fractional differential equations of corresponding dynamical free and forced processes are obtained by using method of Bernoulli’s particular integral and Lalace’s transform method asymptotic averaged method. It is shown that to one mode vibrations correspond a infinite sets correspond the like or two-frequency regime for free vibrations induced by initial conditions. Analytical solutions show us that connection between beams, as well as between plates, and also between belts coursed appearance of like two-frequency regime of time functions correspond to one eigen amplitude function of one mode from infinite mode sets, and also that time functions of different the -family or -family vibration modes are uncoupled. The partial differential equations as well as partial integro differential equations of transversal stochastic vibration of a parametrically excited beam was derived. The influence of rotatory inertia of beam cross section and transverse shear of beam cross section under the transverse force, and the corresponding members in the partial differential equation are taken into account. Bernoulli particular integral method and Lagrange method of variation constant are used for the transformation problem. The asymptotic averaged method is used for obtaining the first approximation of Itô stochastic differential equations. The sets of Lyapunov exponents are obtained.
CENTAR ZA NELINEARNU DINAMIKU I AKTIVNE KONSTRUKCIJE MAŠINSKOG FAKULTETA U NIŠU VAS POZIVA DA UČESTVUJETE U RADU SEMINARA
Nelinearna dinamika - Milutin Milanković
U UTORAK, 12. DECEMBRA 2006. godine sa početkom u 14,00 časova u Laboratoriji za eksperimentalnu mehaniku – 307.
Alexander P. SeyranianD.Sc, Ph.D, Leading Research Fellow Institute of Mechanics, Moscow State Lomonosov University održaće predavanje pod nazivom
MULTIPARAMETER STABILITY THEORY WITH MECHANICAL APPLICATIONS
Kratak sadržaj: A new multiparameter bifurcation theory of eigenvalues of matrix and linear differential operators is presented which is a key point for stability study of systems with finite degrees of freedom as well as distributed systems. Two important cases of strong and weak interactions (collisions) are distinguished and geometrical interpretation of these interactions is given. The presence of several parameters and the absence of differentiability of multiple eigenvalues constitute the main mathematical difficulty of the analysis. With presented multiparameter bifurcation theory of eigenvalues we analyze singularities of stability boundaries and give a consistent description and explanation for several interesting mechanical effects like gyroscopic stabilization, flutter and divergence instabilities, transference of instability between eigenvalue branches, destabilization and stabilization by small damping, disappearance of flutter instability, parametric resonance in periodically excited systems etc. [1] Seyranian, A. P., and Mailybaev, A.A. 2004. Multiparameter Stability Theory with Mechanical Applications, New Jersey: World Scientific.
CENTAR ZA NELINEARNU DINAMIKU I AKTIVNE KONSTRUKCIJE MAŠINSKOG FAKULTETA U NIŠU VAS POZIVA DA UCESTVUJETE U RADU SEMINARA
U CETVRTAK, 1. JUNA 2006. godine sa pocetkom u 12,00 casova u Laboratoriji za eksperimentalnu mehaniku – 307.
J.T. Katsikadelis Academy of Athens, Office of Theoretical and Applied Mechanics & School of Civil Engineering, National Technical University of Athens, Greece.
The BEM for Nonlinear Vibrations of Plates with Variable Stiffness and Mass Properties
Apstrakt: The BEM (Boundary Element Method) is developed for dynamic analysis of plates with functionally graded stiffness and mass properties (e.g. variable thickness) undergoing large deflections. Although there is an extensive literature on plates with constant stiffness and mass properties (e.g. uniform thickness), a rather limited amo
Mašinski fakultet Univerziteta u Nišu organizuje Treću međunarodnu konferencija "Mašinsko inženjerstvo u XXI veku". Konferencija će se održati u Nišu 17-18. septembra 2015
Mašinski fakultet u Nišu će 1. oktobra ove godine dodeliti zlatne indekse generaciji studenata koja je upisala Mašinski fakultet u Nišu pre 50 godina, školske 1965/66 godine.
Ove i sledece nedelje svečanim pro- gramima Univerzitet u Nišu obeležava pola veka postojanja i rada. Programi su namenjeni svim članovima Univer- ziteta, studentima i gradjanima Niša