Technological scouting of bi-material face masks: experimental analysis on real faces.

The need for personal protective equipment rapidly grew during the COVID-19. Companies had to face problems related to their products' sustainability, adherence, and comfortability. Designing a face mask with proper adherence and comfortability in wearing and breathing became a matter of great importance. In this work, the adherence of an innovative face mask and its comfortability were experimentally tested with real faces, considering the deformation of the mask and the soft facial tissues. A stereophotogrammetric acquisition was made of the face with the face mask during these tests. A comparison between the geometries of the face and the mask, undeformed and deformed, gave the respective deformations. The force applied by the mask to the face was calculated, measuring the elastic strain of the mask bands during wearing and the deformation.