ASCE-ASME J. Risk and Uncert. in Engrg. Sys., Part B: Mech. Engrg.
In the last decades, the research community has shown an increasing interest in the engineering a... more In the last decades, the research community has shown an increasing interest in the engineering applications of fractional calculus, which allows to accurately characterize the static and dynamic behavior of many complex mechanical systems, e.g., the nonlocal or nonviscous constitutive law. In particular, fractional calculus has gained considerable importance in the random vibration analysis of engineering structures provided with viscoelastic damping. In this case, the evaluation of the dynamic response in the frequency domain presents significant advantages, once a probabilistic characterization of the input is provided. On the other hand, closed-form expressions for the response statistics of dynamical fractional systems are not available even for the simplest cases. Taking advantage of the residue theorem, in this paper the exact expressions of the spectral moments of integer and complex orders (i.e., fractional spectral moments of linear fractional oscillators driven by acceler...
ABSTRACT For civil engineering structures it becomes of primary importance to detect and quantify... more ABSTRACT For civil engineering structures it becomes of primary importance to detect and quantify damage at the early stage, much before structural collapse. One of the greatest difficulties in damage detection lays in the low damage sensitivity of structural response. When a very low level of damage occurs, for instance a little variation in structural stiffness, this phenomenon cannot be detected either in time domain or in frequency domain. Different structural response characteristics can be used for this purpose including modal data (Adams et al., 1991; Cerri and Vestroni, 2000), curvature measures (Luo and Hanagud, 1997; Ratcliffe, 1999), frequency response functions (Sampaio et al, 1999; Lee and Shin, 2002) and strain energy (Shi et al., 1998; Cornwell et al., 1999). A robust technique should be able to detect damage at very low level; engineers need tools to recognize when dangerous situations may be initiated and well hidden behind an apparent structural integrity condition, avoiding the use of any complex algorithm. Recently it has been developed a damage identification procedure very useful to detect low variation of structural stiffness (Cottone et al., 2006; Di Paola et al., 2006; Barone et al, 2006). This procedure is based on applying Hilbert Transform, to obtain the analytical representation of the system response to an impulse. In fact by considering some characteristics of the analytical signal, such as the phase, since the latter is very sensitive in detecting damage at early stage, it has been possible to develop a damage identification procedure based on a functional of the square of the difference between the characteristics of the analytical theoretical and measured signal. So far this investigation has been performed on 2 the impulse response function, now we wonder: what about a damage detection procedure based on the analysis of the structural response to the environmental noise. The aim of this paper is just to provide a damage detection procedure analyzing the response of a shear-building type to a stochastic process that may proper simulate environmental noise.
The Open Construction and Building Technology Journal, 2016
Cultural heritage is the set of things, that having particular historical cultural and aesthetic ... more Cultural heritage is the set of things, that having particular historical cultural and aesthetic are of public interest and constitute the wealth and civilization of a place and its people. Sharpen up methodologies aimed at safeguarding of monuments is crucial because the future may have in mind the historical past. Italy is a country that has invested heavily on its historical memory returned in large part by the historical building or the monuments. Furthermore, culture represents a fundamental indicator of the growth of the culture of a country. Consider a monitoring project of one of the most Impressive theater in the world, like “Teatro Massimo” in Palermo (Italy), means to add value to both of the issues mentioned above. Among several methods providing useful information about the conservation status of the structures, dynamic monitoring techniques are suitable to check and restore the global behavior of the buildings. The anomalous features diagnosis of the structural dynamic...
ASCE-ASME J. Risk and Uncert. in Engrg. Sys., Part B: Mech. Engrg.
In the last decades, the research community has shown an increasing interest in the engineering a... more In the last decades, the research community has shown an increasing interest in the engineering applications of fractional calculus, which allows to accurately characterize the static and dynamic behavior of many complex mechanical systems, e.g., the nonlocal or nonviscous constitutive law. In particular, fractional calculus has gained considerable importance in the random vibration analysis of engineering structures provided with viscoelastic damping. In this case, the evaluation of the dynamic response in the frequency domain presents significant advantages, once a probabilistic characterization of the input is provided. On the other hand, closed-form expressions for the response statistics of dynamical fractional systems are not available even for the simplest cases. Taking advantage of the residue theorem, in this paper the exact expressions of the spectral moments of integer and complex orders (i.e., fractional spectral moments of linear fractional oscillators driven by acceler...
ABSTRACT For civil engineering structures it becomes of primary importance to detect and quantify... more ABSTRACT For civil engineering structures it becomes of primary importance to detect and quantify damage at the early stage, much before structural collapse. One of the greatest difficulties in damage detection lays in the low damage sensitivity of structural response. When a very low level of damage occurs, for instance a little variation in structural stiffness, this phenomenon cannot be detected either in time domain or in frequency domain. Different structural response characteristics can be used for this purpose including modal data (Adams et al., 1991; Cerri and Vestroni, 2000), curvature measures (Luo and Hanagud, 1997; Ratcliffe, 1999), frequency response functions (Sampaio et al, 1999; Lee and Shin, 2002) and strain energy (Shi et al., 1998; Cornwell et al., 1999). A robust technique should be able to detect damage at very low level; engineers need tools to recognize when dangerous situations may be initiated and well hidden behind an apparent structural integrity condition, avoiding the use of any complex algorithm. Recently it has been developed a damage identification procedure very useful to detect low variation of structural stiffness (Cottone et al., 2006; Di Paola et al., 2006; Barone et al, 2006). This procedure is based on applying Hilbert Transform, to obtain the analytical representation of the system response to an impulse. In fact by considering some characteristics of the analytical signal, such as the phase, since the latter is very sensitive in detecting damage at early stage, it has been possible to develop a damage identification procedure based on a functional of the square of the difference between the characteristics of the analytical theoretical and measured signal. So far this investigation has been performed on 2 the impulse response function, now we wonder: what about a damage detection procedure based on the analysis of the structural response to the environmental noise. The aim of this paper is just to provide a damage detection procedure analyzing the response of a shear-building type to a stochastic process that may proper simulate environmental noise.
The Open Construction and Building Technology Journal, 2016
Cultural heritage is the set of things, that having particular historical cultural and aesthetic ... more Cultural heritage is the set of things, that having particular historical cultural and aesthetic are of public interest and constitute the wealth and civilization of a place and its people. Sharpen up methodologies aimed at safeguarding of monuments is crucial because the future may have in mind the historical past. Italy is a country that has invested heavily on its historical memory returned in large part by the historical building or the monuments. Furthermore, culture represents a fundamental indicator of the growth of the culture of a country. Consider a monitoring project of one of the most Impressive theater in the world, like “Teatro Massimo” in Palermo (Italy), means to add value to both of the issues mentioned above. Among several methods providing useful information about the conservation status of the structures, dynamic monitoring techniques are suitable to check and restore the global behavior of the buildings. The anomalous features diagnosis of the structural dynamic...
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Papers by Giacomo Navarra