GONZÁLEZ-CARBAJAL , Javier

The present thesis is concerned with the nonlinear dynamics of vibrating systems excited by unbalanced motors. The main focus is the reciprocal (nonideal) interaction which in general exists between the dynamics of the exciter –the unbalanced motor– and that of the vibrating system. Two models were analytically and numerically studied. First, a...

This study is the natural continuation of a previous paper of the authors González-Carbajal and Domínguez in J. Sound Vib. (Under revision), where the possibility of finding Hopf bifurcations in vibrating systems excited by a nonideal power source was addressed. Herein, some analytical tools are used to characterize these Hopf bifurcations,...

This paper revisits the problem of an unbalanced motor attached to a fixed frame by means of a nonlinear spring and a linear damper. The excitation provided by the motor is, in general, nonideal, which means it is affected by the vibratory response. Since the system behaviour is highly dependent on the order of magnitude of the motor...

Transfer functions are constantly used in both Seismology and Geotechnical Earthquake Engineering to relate seismic ground motion at different depths within strata. In the context of diffusive theory, they also appear in the expression of the imaginary part of 1D Green's functions. In spite of their remarkable importance, their mathematical...

This paper focuses on the Nonlinear Normal Modes of simply supported beams with unrestrained axial displacements. Two different configurations are considered, depending on whether longitudinal displacements are allowed at one end of the beam or at both ends. An integro-differential equation is obtained for the transverse displacement of the...

This paper investigates the dynamics of a Duffing oscillator excited by an unbalanced motor. The interaction between motor and vibrating system is considered as nonideal, which means that the excitation provided by the motor can be influenced by the vibrating response, as is the case in general for real systems. This constitutes an important...

This study addresses the influence of the Sommerfeld effect on the behaviour of vibrocompacting machines driven by unbalanced electric motors. Based on a simplified model with 4 degrees of freedom previously published by the authors, we investigate the dynamics of quasistatic vibrocompaction processes, i.e. those in which the compaction is...

This paper considers a kind of industrial process where a granular material is compacted by using vibration machines. In particular, attention is focused on the vibrocompaction of quartz agglomerates, where the vibration is produced by rotation of unbalanced electric motors. A four degree-of-freedom nonlinear model, which includes contact and...

The rotating beam problem has been extensively used as a benchmark for testing nonlinear finite element implementations. The remarkable characteristic of this benchmark is the coupling between axial a transverse deformations due to the centrifugal forces. The rotating beam dynamics exhibits a centrifugal stiffening effect that can only be...

This paper aims at studying the influence of the different support types on the free nonlinear vibration frequency of a beam, both by analytical and numerical approaches and its dependence on the vibration amplitude. First, an analytical study of two cases of simply supported beams is carried out by using the nonlinear normal modes (NNM) and...

This article investigates the appearance of periodic mechanical oscillations associated with the transition between static and dynamic friction regimes. The study employs a mechanical system with one degree of freedom and a friction model recently proposed by Brown and McPhee, whose continuity and differentiability properties make it...

This paper describes a novel method for the estimation of the trajectory and orientation of a rigid body moving along a railway track. Compared to other recent developments in the literature, the presented approach has the significant advantage of using inertial sensors only, excluding global position and orientation sensors. The excluded...