0000000000379963
AUTHOR
G. Muscolino
Mode-superposition correction method for deterministic and stochastic analysis of structural systems
The role played by the modal analysis in the framework of structural dynamics is fundamental from both deterministic and stochastic point of view. However the accuracy obtained by means of the classical modal analysis is not always satisfactory. Therefore it is clear the importance of methods able to correct the modal response in such a way to obtain the required accuracy. Many methods have been proposed in the last years but they are meaningful only when the forcing function is expressed by an analytical function. Moreover in stochastic analysis they fail for white noise excitation. In the paper a method able to give a very accurate response for both deterministic and stochastic input is p…
A perturbation approach for the response of dynamically modified structural systems
The problem of the structural analysis under changes of dynamical parameters is of particular interest. This is due to the fact that often the real structures are different from the predicted ones. In this paper, an unconditionally stable step-by-step procedure, able to evaluate the deterministic response of linear structures with modifications, is presented. The proposed procedure requires the evaluation of the transition matrix, which is the fundamental operator of the step-by-step solution, by means of a perturbation approach. This technique overcomes the difficulties connected with the evaluation of the eigenproperties of the modified structures usually required to obtain the transition…
Non Gaussian closure techniques for the analysis of R-FBI isolation system
The Resilient-Friction Base Isolator (R-FBI) stochastic response under severe ground motion modelled as a stationary and non-stationary zero mean stochastic white noise processes is performed. The moment equation approach is applied and the non-normal response is obtained by means of a non-Gaussian closure technique, based on the Gram-Charlier asymptotic expansion of the response probability density function. Results are compared with the equivalent non linearization technique and with results obtained by means of Monte Carlo simulation.
Extension of The Stochastic Differential Calculus To Complex Processes
In structural engineering complex processes arise to predict the first excursion failure, fatigue failure, etc. Indeed to solve these problems the envelope function, which is the modulus of a complex process, is usually introduced. In this paper the statistics of the complex response process related to the envelope statistics of linear systems subjected to parametric stationary normal white noise input are evaluated by using extensively the properties of stochastic differential calculus.
Crack identification in a beam by measure of the response to white noise
The aim of this paper is to inspect the vibrational response of a beam with an edge non-propagating crack by means of stochastic analysis, in order to detect the presence and the location of structural damage. The non- linear behavior of the beam due to the opening and closing of the crack is fully exploited. The non-linearity measure is based on the response evaluation of the beam subjected to a white noise process. Both numerical and experimental investigations regarding a cantilever beam with a crack are reported in the paper.
Gaussian and non-Gaussian stochastic sensitivity analysis of discrete structural systems
Abstract The derivatives of the response of a structural system with respect to the system parameters are termed sensitivities. They play an important role in assessing the effect of uncertainties in the mathematical model of the system and in predicting changes of the response due to changes of the design parameters. In this paper, a time domain approach for evaluating the sensitivity of discrete structural systems to deterministic, as well as to Gaussian or non-Gaussian stochastic input is presented. In particular, in the latter case, the stochastic input has been assumed to be a delta-correlated process and, by using Kronecker algebra extensively, cumulant sensitivities of order higher t…
Stochastic sensitivity of steel frames with connection dampers by modal analysis
A procedure for evaluation of dynamic response sensitivity of multistory steel frames with added viscoelastic beam to column connections by modal analysis is presented. The connection behavior is modeled by a Kelvin-Voigt element, consisting of a rotational spring and a dashpot connected in parallel. Consistent mass, stiffness and damping matrices of the multistory frame are utilized, leading to a structure modeling as a non-classically damped system. The procedure is based on the dynamic modification method, that allows to evaluate the response of non-classically damped structure by modal superposition, without transformation in the complex space. The differential equations governing the e…
Filter approach to the stochastic analysis of MDOF wind-excited structures
Abstract In this paper, an approach useful for stochastic analysis of the Gaussian and non-Gaussian behavior of the response of multi-degree-of-freedom (MDOF) wind-excited structures is presented. This approach is based on a particular model of the multivariate stochastic wind field based upon a particular diagonalization of the power spectral density (PSD) matrix of the fluctuating part of wind velocity. This diagonalization is performed in the space of eigenvectors and eigenvalues that are called here wind-eigenvalues and wind-eigenvectors, respectively. From the examination of these quantities it can be recognized that the wind-eigenvectors change slowly with frequency while the first wi…