Search results for "Bifurcation"

showing 4 items of 204 documents

Positive solutions for nonlinear Robin problems

2017

We consider a parametric Robin problem driven by the p-Laplacian with an indefinite potential and with a superlinear reaction term which does not satisfy the Ambrosetti-Rabinowitz condition. We look for positive solutions. We prove a bifurcation-type theorem describing the nonexistence, existence and multiplicity of positive solutions as the parameter varies. We also show the existence of a minimal positive solution $\tilde{u}_\lambda$ and establish the monotonicity and continuity of the map $\lambda\to \tilde{u}_\lambda$.

truncation and comparison techniquesminimax positive solutionSettore MAT/05 - Analisi Matematicalcsh:MathematicsMathematics::Analysis of PDEssuperlinear reactionRobin boundary condition superlinear reaction truncation and comparison techniques bifurcation-type result minimax positive solutionRobin boundary conditionbifurcation-type resultlcsh:QA1-939
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Variational principle and bifurcations in stability analysis of panels

2014

In this paper, the stability of a simply supported axially moving elastic panel is considered. A complex variable technique and bifurcation theory are applied. As a result, variational equations and a variational principle are derived. Anal- ysis of the variational principle allows the study of qualitative properties of the bifurcation points. Asymptotic behaviour in a small neighbourhood around an arbitrary bifurcation point is analyzed and presented. It is shown analytically that the eigenvalue curves in the (ω, V0) plane cross both the ω and V0 axes perpendicularly. It is also shown that near each bifur- cation point, the dependence ω(V0) for each mode approximately follows the shape of …

variational principlebifurkaatiobifurcationlujuusoppivariaatiolaskentavakavuusmatemaattiset mallitstability analysisdynamiikkakimmoisuus
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Variational approach for analysis of harmonic vibration and stabiligy of moving panels

2014

In this paper, the stability of a simply supported axially moving elastic panel (plate undergoing cylindrical deformation) is considered. A complex variable technique and bifurcation theory are applied. As a result, variational equations and a variational principle are derived. Analysis of the variational principle allows the study of qualitative properties of the bifurcation points. Asymptotic behaviour in a small neighbourhood around an arbitrary bifurcation point is analyzed and presented. It is shown analytically that the eigenvalue curves in the (ω, V0) plane cross both the ω and V0 axes perpendicularly. It is also shown that near each bifurcation point, the dependence ω(V0) for each m…

variational principlecomplex variable techniquesbifurcation theoryaxially moving beamaxially moving panel
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An analytical-numerical study of dynamic stability of an axially moving elastic web

2015

This paper is devoted to a dynamic stability analysis of an axially moving elastic web, modelled as a panel (a plate undergoing cylindrical deformation). The results are directly applicable also to the travelling beam. In accordance with the dynamic approach of stability analysis, the problem of harmonic vi- brations is investigated via the study of the dependences of the system’s nat- ural frequencies on the problem parameters. Analytical implicit expressions for the solution curves, with respect to problem parameters, are derived for ranges of the parameter space where the natural frequencies are real-valued, corresponding to stable vibrations. Both axially tensioned and non-tensioned tra…

värähtelytaxially movingharmonic vibrationvakavuusnumeerinen analyysistabilitymatemaattiset mallitbifurcation pointwebdynamiikkakimmoisuus
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