1,720,977 research outputs found
State of the Art on New Technologies for Safeguarding Cultural Heritage: A Short Report and Some Personal Points of View from Italy
No full textThe main purpose of the paper is the discussion of techniques and/or methodologies, which are susceptible of further developments and may be chosen for more extensive use in the framework of modern strategies aimed at the protection of cultural heritage as a whole. Again in the author’s opinion, a wide range of applications at a reasonable cost is a crucial (often forgotten) issue for any official institution involved in conservation problems. Indeed, there is a rather common trend towards very expensive (and sometime useless) plans for the protection of a few monuments, while a large number of historical buildings is eventually ignored owing to lack of funds
Damage assessment in concrete dams: a Kalman Filter approach
No full textThe paper focuses on the estimate of stiffness parameters concerned with large dams. Experimental records taken during shaking tests and/or micro-seismic activity are assumed as input data and the Kalman filtering approach is applied in order to determine optimal values of unknown elastic constants. The subject is related to the issue of monitoring, since possible changes of elastic properties can be interpreted as “indicators” of ongoing deterioration processes. The method has been implemented with the aim of estimating pairs of parameters (bulk modules and shear modules). In this way it is possible to consider undesired effects due to isotropic and deviatoric stress components, in accordance to the theoretical framework upon which several damage models are based.
Numerical simulations show that the technique discussed in the paper is suitable to detect a decrease of mechanical properties if adequate tests are carried out at regular intervals
FNA Method applied to Nonlinear Dynamic Structural Analysis with Passive Control Devices
No full textNumerical modelling of masonry: A material model accounting for damage effects and plastic strains
No full textMonitoring of Damaged Zones in Large Dams: An Error Indicator to Evaluate a Non-Destructive Testing Procedure
No full text
A Kalman Filter Approach Applied to the Qualitative Assessment of Structural Damage
No full textThe paper is concentrated on a non-traditional application of the Kalman Filter algorithm and outlines a procedure that can be used to assess structural damage. The technique is essentially based on the estimate of unknown stiffness parameters of the structure, whose changes over time can be related to the structure’s deterioration and local damage. In this way, suspected areas can be detected and further investigated. In our approach, it is assumed that experimental records are taken at regular intervals by means of shaking tests and/or during micro-seismic activity, so that optimal values of convenient parameters can be determined by solving an inverse problem. The proposed procedure has been applied to the estimate of bulk and shear modules, whose changes denote possible damage due to isotropic and deviatoric stress components, in accordance with the theoretical framework which several damage models are based on. More specifically, we simulated experimental tests on dam structures by assuming some damage at certain locations. Finally, an error indicator was introduced, with the aim of finding an objective measure of the accuracy of the results obtained by solving the inverse problem
System Identification Applied to Dam Safety and Integrity
No full textThe problem of damage assessment in dam structures is addressed: the aim is to employ a system identification technique (Kalman Filter) and determine unknown elastic constants, whose values can be related to the current structural conditions and can be interpreted as ‘indicators’ of degradation phenomena.
Namely, the final objective is the estimate of pairs of parameters (bulk modulus and shear modulus) in critical zones, where material properties might be affected by damage processes: the use of both moduli is justified by the fact that structural damage is often due to the combined action of isotropic and deviatoric stress components, as explained by various theoretical models.
After giving some basic information about the proposed method, we briefly discuss numerical simulations, which show that the Kalman Filter can be conveniently exploited to detect areas where damage has occurred and/or is spreading and/or is likely to be present
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