It is shown that among the various damping mechanisms that are generally encountered in a mechanical structure, only the “viscous component” actually accounts for energy loss. The remaining portion of the damping force is due to non-linearities, which do not dissipate energy. Consequently, a linear model of a vibratory mechanical system involves only viscous damping, although the damping factor...

Abstract Modal parameter estimation of randomly and ambient excited structures using output-only system identification techniques has become a recently essential issue for assessment of engineering structures, structural health monitoring and structural control. A number of mathematical models on the output-only identification techniques have been developed in the time domain, in the frequency ...

Different expressions have been developed to determine damping of structures based on various hysteretic models and ductility levels. Since Slenderness ratio is an important parameter on the hysteretic behavior of special concentrically- braced frames (SCBF), in this paper new expressions for determination of damping of such frames are developed based on slenderness ratio and ductility. Two typ...

We study the eigenvalues and eigenspaces of the quadratic matrix polynomial Mλ + sDλ + K as s → ∞, where M and K are symmetric positive definite and D is symmetric positive semi-definite. The work is motivated by its application to modal analysis of finite element models with strong linear damping. Our results yield a mathematical explanation of why too strong damping may lead to practically un...

Our aim is to optimize the damping of a linear vibrating system. As the optimality criterion we use the one where the penalty function is given as the average total energy over all initial states of unit energy, which is equal to the trace of the corresponding Lyapunov solution multiplied by a matrix corresponding to the chosen measure on the set of initial states. We solve this optimization pr...

Traditionally, the estimation of modal parameters from a set of measured data has required significant experience. However, as the technology has matured, increasingly, analysis is being performed by less experienced engineers or technicians. To address this development, frequently software solutions are focusing upon either wizard-based or autonomous/semiautonomous approaches. A number of auto...

This paper investigates damping ratio in micro-beam resonators based on magneto-thermo-elasticity. A unique aspect of the present study is the effect of permanent magnetic field on the stiffness and thermo-elastic damping of the micro resonators. In our modeling the theory of thermo-elasticity with interacting of an externally applied permanent magnetic field is taken into account. Combined the...

Modal frequencies and damping coefficients are crucial quantities to characterize predict the structural behaviour of wind excited structures. Wind turbines in parked conditions can be treated as telecommunication or lighting towers, for which a fair amount experimental studies is available. However, natural may change dramatically operating conditions. In this case, investigations quite few li...

Modal parameter analysis is a common method for structural characteristic analysis. To accurately identify the modal parameters that describe vibration characteristics of structure, chassis frame rice transplanter taken as research object. The least squares complex frequency domain method, admittance circle and peak picking are used to process measured signal. parameters, such natural frequency...

A new wind-resistant design optimization method for twin towers by utilizing link bridges, named as the Modal Substructure (MSS) method, is proposed. The MSS combines benefits of engineering approaches and theoretical analysis methods to achieve efficient wind-induced vibration control tailored specific tower projects. involves three main steps: (1) establishing objectives based on response cha...