Theoretical assessment of different ultrasonic configurations for defects detection in composite components

It is well known that structures’ safety is crucial and of great importance. Part of their maintenance procedure is structural inspection, which is currently performed with the aid of Non Destructive Testing techniques, aiming to detect structural defects in damaged or flawed components and prevent a catastrophic failure by substituting or repairing them. The objective of this work is the theoretical assessment of different ultrasonic configurations that could maximize delamination defect detection in composite components. Modeling study was performed using simulation software, where physical models representative of laminated Carbon Fiber Reinforced Polymer composites, consisting of a variety of artificial delamination defect modes (different sizes and depth), were numerically tested. Different ultrasonic configurations on both the positioning and the firing of the probe's elements including Phased Array delay timings and sampled array techniques were investigated and are presented in this paper. The potential of Full Matrix Capture data acquisition technique, modelled here, along with the post processing Total Focusing Method reconstruction approach is also assessed in terms of their ability to enhance defect detectability and visualization

Inspecting historical vaulted ceilings by means of physical and chemical analyses : an integrated approach combining active infrared thermography and reflectance spectroscopy

The present study discusses the experimental physicochemical results obtained from the historical vaulted ceilings of an ancient church located in central Italy. Infrared thermography (IRT) in the active configuration was used to map subsurface defects caused by a seismic event and to discover buried structures, while the visible and near-infrared (VIS-NIR) fibre optics diffuse reflectance spectroscopy (FORS) technique was applied to identify the pigments of wall paintings decorating the vault. Historical photographs are useful to readers in order to clarify the state of conservation before and after the earthquake that took place in 2009. The combination of the experimental results can be useful in restoration processes

How to retrieve information inherent to old restorations made on frescoes of particular artistic value using infrared vision?

Restoration is the methodological moment in which the artwork is appreciated in its material form and in its historical and aesthetic duality, with a view to transmitting it to the future” (C. Brandi). This work is inspired by this memorable definition. It is based both on the study of an ancient fresco and a fresco’s reproduction, assessing the principal defects afflicting this type of structures and aiming at reconstructing the restoration phases through the definition of a combined thermographic and reflectographic procedure that has the purpose of mapping the quality of the restoration itself and thinking of the future. According to Brandi, the timeline for an artwork can be divided into three parts. The first corresponding to the duration of the creative process conducted by the artist and culminating with the completion of the work. The second corresponds to an interval, which is the historical time elapsing from the conclusion of the work to the present. Last but not least, the moment, which is acknowledged in the consciousness of the observer who takes the responsibility of transmitting it to the future. The observer might also be the restorer. Indeed, the restoration takes place at the latter stage and it aims at re-establishing the potential unity of the artwork, to the highest level possible, without producing an artistic or historical forgery and without erasing any trace of the natural passage of time on the artwork. The infrared vision might help to reveal whether the restoration is done properly or not