Cultural heritage: From ENEA and Cnr an acoustic technology to assess damage caused by humidity

11/11/2021

Preemptively assessing water damage by infiltration on works of art and archaeological sites through sound. That’s the purpose of an innovative diagnostic device [1] ENEA (coordinator) and Cnr are developing as part of the project ReMEDIA [2], also funded by the Lazio Region, to turn the prototype into a commercial product thanks to the support of regional companies in the cultural heritage sector.

"The advantages of this technology go from non-invasiveness to high performance, which allow to obtain accurate information on the extent and distribution of damage caused by humidity on ancient walls and artifacts, an increasingly widespread problem capable of altering structure and elastic properties of the artworks, particularly archaeological sites below street level like catacombs or sepulchral artifacts, or built on Roman foundations ", explained project manager Francesco Colao, researcher at the ENEA Diagnostics and Metrology Laboratory of the Frascati Research Center.

The techniques [3] currently used to determine the moisture content, both in the monitoring phase and during planning of restoration interventions, have numerous practical disadvantages, due to the invasiveness and time needed to acquire and analyse data. "In order to overcome these limitations the use of acoustic imaging, on which our technology is based and that guarantees non-destructive and non-invasive diagnostics, is very promising. Simply by stimulating the structure to be analyzed with a sound pressure or ultrasound field and detecting the acoustic response to the stimulus ”, pointed out Paola Calicchia, head of the Cnr LARCH Laboratory - Laboratory of Acoustics Research Applications for Cultural Heritage.

The measurement of the absorption of acoustic energy by ancient walls and artifacts is at the core of the ENEA and Cnr device. The system uses an acoustic source in the audio band (100 Hz - 20 kHz) to stimulate with a sound wave the surface to analyse, detecting the so-called impulse response

The acoustic response of a material to a stress coming from an external pressure field depends on the elastic properties of the material. In this way, the system conducts a non-destructive diagnosis of the elements of artistic interest. That’s not all. A further study of the method of measurement and multifrequency analysis has shown in recent years its applicability also on the typical diagnostic investigations of the structural damage of masonry surfaces, artifacts with artistic finishes such as frescoed surfaces, glazed ceramics, stuccos and even paintings on wooden panels. By providing frequency-resolved acoustic images, the system can detect detachments, delaminations, cracks, sub-surface cavities of various kinds, as well as weakening or hardening of structures and composite materials.

The technology will be used for the first time next year in some historical sites in Rome, including the catacombs of Priscilla. "These tests will not only fine-tune our technology, but also provide an opportunity to meet and collaborate with companies and experts of the restoration and cultural heritage sector," concluded Colao.

For more information please contact:

Francesco Colao – ENEA, Diagnostics and Metrology Laboratory– francesco.colao@enea.it

Paola Calicchia – CNR, LARCH Laboratory- Laboratory of Acoustics Research Applications for Cultural Heritage, paola.calicchia@cnr.it

  1. Presentation Page of the Call for Research teams : http://www.lazioinnova.it/bandi-post/progetti-gruppi-ricerca-2020/
  2. ENEA Presentation Page: https://www.enea.it/it/fusione-e-sicurezza-nucleare/progetto-remedia
  3. CNR Presentation page: https://www.ispc.cnr.it/it_it/2021/05/12/por-fesr-lazio-2014-2020-finanziati-4-progetti-di-ricerca-presentati-dal-cnr-ispc/
  4. Details on the ACEADD technique : https://www.sciencedirect.com/science/article/abs/pii/S0263224117305158

 

[1] ACoustic Energy Absorption Diagnostic Device (ACEADD)

[2]  REsearch and diagnostics of contrast MEthods  to Deterioration caused by humidIty in cultural heritAge

[3] Gravimetric tests, infrared thermography, microwave, holographic radar, unilateral nuclear magnetic resonance and evanescent field dielectrometry.

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