As many studies show, there is a relation between the tissue’s mechanical characteristics and some specific diseases. Knowing this relationship would help early diagnosis or microsurgery. In this paper, a new method for measuring the viscoelastic properties of soft materials at the microscale is proposed. This approach is based on the adoption of a microsystem whose mechanical structure can be ...

The damping in a carbon fiber reinforced plastic (CFRP) laminate is greater than that which occurs in most metallic materials. In the supercritical regime, the damping can trigger unstable whirl oscillations, which can have catastrophic effects. The vibrations occurring in a supercritical composite drive shaft are investigated here in order to predict instabilities of this kind. A simply suppor...

A = aerodynamic stiffness matrix C = speed of sound E = complex Fourier matrix f , F = physical and modal forces h = height of stream tube j = imaginary unit K, M = stiffness and mass matrices NB = number of blades P, Q = modal transformation matrices p = flow pressure Q = flow mass flux at the boundary q = generalized (modal) coordinate s = distance along the boundary T = period of flow unstea...

This paper presents two time methods to identify weak non-linearities on damping and stiffness of a free vibrating system. Only the displacement is known. The first method is a direct parameter estimation method : using the measured displacement data of the system we obtain by numerical differentiation velocity and acceleration. A linear system containing the parameters is then derived. A least...

At small scales, the fabrication of robots from off-theshelf structural materials, sensors and actuators becomes increasingly difficult. New manufacturing methods such as Shape Deposition Manufacturing offer an alternative approach in which sensors and actuators are embedded directly into three-dimensional structures without fasteners or connectors. In addition, structures can be fabricated wit...

The purpose of this paper is to describe the possibilities of studying the influence of forces external variables on the stability of motion of dynamical systems modeled by systems of differential equations with periodic coefficients of stability. The method is applied to analyze the influence of external harmonic forces on the stability of motion of the pantograph couple contact wire electric ...

The increasing use of advanced sensing technologies for strain measurements necessitates the development of strain-based identification methodologies. In this study, a three-step neural network strategy, called direct soft parametric identification (DSPI), is presented to identify the member stiffness and damping parameters of a truss structure directly from free vibration-induced strains. The ...

This article develops a simple linear model for the motion of a Stewart platform in a stationary position. That is, the situation where the platform is at rest and is then subject to an impulsive disturbance. The hydraulic actuators are modelled as simple spring-dashpot systems and the stiffness and damping matrices of the system are derived. It is found that the damping and stiffness matrices ...