Abstrakt

The paper provides new experimental evidence for vulnerable artifacts on the dependence of failure strain on the loading rate corresponding to typical environmental loads lasting between hours and months. Animal glue-based ground was chosen for this study as an easily available, hygroscopic and brittle material as well as due to its abundance in collections and its relevance when discussing the risk of mechanical damage to objects. Gesso specimens were tested using dynamic mechanical analysis and tensile testing at different frequencies, under a variety of loading rates and temperatures. The time-temperature superposition principle was used to predict the material response to slow deformations (lasting hours to months) that are otherwise inaccessible on laboratory timescales. The results demonstrate that brittle materials such as animal glue-based grounds do not benefit from longer cycles of applied loads as failure strain is not time-dependent within the investigated timescale.