Recent work in the field of robotics optimal control has focused on designing and employing variable impedance actuators. Such actuators provide a high dynamic range and fast response. Until now, impedance modulation has been restricted to physical stiffness alone, while its other components, such as damping, are set to a fixed value. In this work the influence of introducing variable damping i...

In the present paper, the aeroelastic stability of helicopter rotor blade is determined using Aeroelastic Frequency Response Function. The conventional methods of aeroelastic stability usually use an iterative procedure while the present method does not require such approach. Aeroelastic Frequency Response Functions are obtained by inverting dynamic stiffness matrix of the aeroelastic system. S...

Supercritical CO2 foil bearings are promising bearing technology for supercritical high-speed turbomachinery. The partial derivative method including complete variable perturbation of the compressible turbulent lubrication Reynolds equation is effective to predict frequency dependent dynamic stiffness and damping coefficients bearings. In this research, structural model was introduced into then...

From a technological point of view, reciprocal structures have the advantage of simplifying considerably connections in the sense that members are connected only by pairs. This constructional advantage has two main consequences: technological constrains are replaced by geometrical constrains and bending moments are increased through the non convergence of members to nodes with multiple connecti...

Combining several materials (“phases”) into a composite material permits creation of new materials with tunable overall response, e.g., elastic properties, which can be related to the elastic moduli, arrangement, and concentrations of the composite’s phases. A recent advance predicts use of one phase having correctly tuned non-positive-definite elastic moduli (i.e., negative stiffness) in a two...

............................................................................................................................... iii ACKNOWLEDGMENTS ............................................................................................................. v TABLE OF CONTENTS ............................................................................................................ vii LIST O...

A coupled model based on finite element method (FEM) and scaled boundary finite element method (SBFEM) for transient dynamic response of large-scale SSI systems is presented. The wellestablished FEM is used for modeling the near-field bounded domains. A local high-order transmitting boundary, which is based on SBFEM and the improved continued fraction solution for the dynamic stiffness matrix, ...

A beam-column element based on the Euler-Bernoulli beam theory is researched for nonlinear dynamic analysis of reinforced concrete (RC) structural element. Stiffness matrix of this element is obtained by using rigidity method. A solution technique that included nonlinear dynamic substructure procedure is developed for dynamic analyses of RC frames. A predicted-corrected form of the Bossak-α met...

seismic base isolation are devices that used to limit the human and material damage caused by an earthquake. this devices diffuse the energy induced at the time of the earthquake before being transferred to the structure.the base isolated structures when subjected to the near-fault eathquakes which contain long-period velocity pulses that may coincide with the period of base isolated structures...

This paper is an overview of quasistatic measurement technique used to determine mechanical properties of sound absorbing materials. Experimental context and behaviour of polymer foam and rock wool are summarized. Concerning parameters are: static and dynamic strains, dynamic effects such as skeleton resonance and coupling with saturating fluid. Material anisotropy and frequency dependance of c...