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2023 Journal article Closed Access
Effects of temperature variations on the modal properties of masonry structures: an experimental-based numerical modelling approach
D. Pellegrini D., Barontini A., Girardi M., Lourenço P. B., Masciotta M. G., Mendes N., Padovani C., Ramos L. F.
Long-term ambient vibration monitoring campaigns show that environmental parameters (such as temperature, humidity, wind speed and direction) can influence the structures' static and dynamic behaviour. In particular, thermal variations can affect the modal characteristics of ancient masonry constructions. This work presents a procedure combining experimental and numerical steps to monitor, assess and model the dynamic behaviour of masonry structures subjected to thermal loads. The procedure is tested and validated through two numerical examples and the simulation of a full-scale masonry structure, the Mogadouro clock tower in Portugal, monitored with accelerometers and temperature and humidity sensors.Source: Structures (Oxford) 53 (2023): 595–613. doi:10.1016/j.istruc.2023.04.080
DOI: 10.1016/j.istruc.2023.04.080

See at: www.sciencedirect.com Restricted | CNR ExploRA

2022 Journal article Open Access OPEN
Tracking the variation of complex mode shapes for damage quantification and localization in structural systems
Masciotta M. G., Pellegrini D.
Real structures mode shapes estimated by modal analysis techniques have a common feature: in most cases they are complex, and their level of complexity can be soundly influenced by the presence and extent of physical damage, which also affects the distribution of energy dissipation mechanisms within the structures. Starting from the contributions available in the literature, the present paper investigates, from a numerical and experimental point of view, the correlation existing between localized damage and variation of global modal complexity indices conventionally employed to quantify the nonproportionality of damping in structural systems. Finally, driven by the inferences made through numerical and experimental test cases by tracking the variation of complex modes over multiple and progressive damage scenarios, a new index for damage localization and quantification is formulated and validated against real data.Source: Mechanical systems and signal processing 169 (2022). doi:10.1016/j.ymssp.2021.108731
DOI: 10.1016/j.ymssp.2021.108731

See at: ISTI Repository Open Access | www.sciencedirect.com Restricted | CNR ExploRA

2020 Journal article Open Access OPEN
Dynamic characterization of progressively damaged segmental masonry arches with one settled support: experimental and numerical analyses
Masciotta M. G., Pellegrini D., Girardi M., Padovani C., Barontini A., Lourenço P. B., Brigante D., Fabbrocino G.
This paper aims to explore the dynamic behavior of a segmental masonry arch subjected to increasing horizontal displacements of one support. To this end, output-only dynamic identification techniques are first used to track the evolution of the dynamic features of the system under progressive damage scenarios and evaluate their sensitivity to settlement-induced cracks. Considerations on the structural response of the segmental arch up to failure are also included. Then, a numerical procedure coupling linear perturbation and modal analysis is applied to simulate the dynamic behavior of the arch over consecutive scenarios, taking into account the influence of the damage on the structure's dynamic properties in an automatic way. The combination of experimental and numerical analyses allows to fully investigate the dynamics of the cracked masonry arch and to shed light on relevant aspects about the effects of settlement-induced cracks on the modal blueprints of masonry arches.Source: Frattura e Integrità Strutturale (2020). doi:10.3221/IGF-ESIS.51.31
DOI: 10.3221/igf-esis.51.31

See at: Frattura ed Integrità Strutturale Open Access | Universidade do Minho: RepositoriUM Open Access | ISTI Repository Open Access | Frattura ed Integrità Strutturale Open Access | Fracture and Structural Integrity Open Access | CNR ExploRA

2020 Conference article Open Access OPEN
A multidisciplinary approach integrating geomatics, dynamic field testing and finite element modelling to evaluate the conservation state of the guimaraes castle's tower keep
Sánchez-Aparicio L. J., Masciotta M. G., Pellegrini D., Conde B., Girardi M., Padovani C., Ramos L. F., Riveiro B.
The development of realistic numerical models able to replicate as closely as possible the actual structural behaviour of heritage buildings is crucial for a thorough assessment of their structur-al performance against exceptional scenarios. In this regard, higher accuracy can be achieved by leveraging a multidisciplinary approach that integrates multiple contributions from different fields, such as geomatics, dynamics and computational modelling. In the present paper, this strategy is applied to the tower keep of the Guimarães castle, in Por-tugal, a masonry fortified structure dating back to the X century. Starting from an accurate la-ser scanner survey, a detailed numerical model has been created resorting to efficient algo-rithms able to represent complex situations. Furthermore, by exploiting the dynamic properties extracted from the processing of vibration data collected during field dynamic testing, the me-chanical characteristics of the constituent materials of the tower have been estimated by means of a model updating technique embedded in a trust-region scheme implemented in the NOSA-ITACA code. The results obtained so far allowed to establish valuable baseline information that will be of pivotal importance to catch possible changes in the tower's response and to perform more in-depth structural analyses.Source: EURODYN 2020 XI International Conference on Structural Dynamics, pp. 2310–2322, 25/11/2020

See at: eurodyn2020.org Open Access | ISTI Repository Open Access | CNR ExploRA