Boundary control, quiet boundaries, super-stability and super-instability

On the longitudinal vibrations of a bar with viscous boundaries: Super-stability, super-instability, and loss of damping

This paper presents the investigation of the longitudinal motions of a bar subjected to viscous boundary conditions at each end. These viscous boundary conditions can also be thought of in terms of boundary feedback control. The system is not self-adjoint and for certain parameter regimes exhibits super-stable, super-unstable, and undamped behavior. Closed form solutions to the response of the ...

Second Order Sliding Mode Control With Finite Time Convergence

In this paper, a new smooth second order sliding mode control is proposed. This algorithm is a modified form of Super Twisting algorithm. The Super Twisting guarantees the asymptotic stability, but the finite time stability of proposed method is proved with introducing a new particular Lyapunov function. The Proposed algorithm which is able to control nonlinear systems with matched structured u...

Global Stability for Thermal Convection in a Couple Stress Fluid Saturating a Porous Medium with Temperature-Pressure Dependent Viscosity: Galerkin Method

A global nonlinear stability analysis is performed for a couple-stress fluid layer heated from below saturating a porous medium with temperature-pressure dependent viscosity for different conducting boundary systems. Here, the global nonlinear stability threshold for convection is exactly the same as the linear instability boundary. This optimal result is important because it shows that lineari...

Numerical Solution of Parabolized Stability Equations Using Super Compact Scheme

Mode coupling instability mitigation in friction systems by means of nonlinear energy sinks: Numerical highlighting and local stability analysis

In this paper, we study a problem of passive control of friction-induced vibrations due to mode coupling instability in breaking systems. To achieve that, the well-known two degrees of freedom Hultèn’s model, which reproduces the typical dynamic behavior of friction systems, is coupled to two ungrounded Nonlinear Energy Sinks (NES). The NES involves an essential cubic restoring force and a line...