Much research has been conducted in recent years on the effect of humidity and temperature on the condition of fragile objects made of various types of materials. The results are being used to better define climate ranges which are acceptable for those objects, with the ultimate goal of more energy efficiency for museums. As Eric Hagan discussed in the introduction to his talk, this important climate question is the background for his work on the analysis of the behavior of wood due to cyclic changes in humidity using acoustic emission. Eric described a custom-made testing system which he designed and built at the CCI for this work. The system, which appears to be quite impressive, includes electronics designed to precisely control cyclic humidity changes in a specially designed chamber. The humidity can be cycled in various forms, such as a simple sine or square wave for modelling work, or simulate measurements actually taken in a museum for more practice-oriented research. The system can be monitored remotely, which makes it interesting for future use on site in museums and historic buildings.
Eric described initial tests conducted on free-standing (unstressed) wood samples, explaining how damage propagation generates sound (acoustic emission). Such results can be related to the changes in humidity. As noted in the abstract for the talk, the talk concentrated on the equipment. It will be interesting to learn how Eric defines damage and damage propagation for historic wood objects, in particular, those which are not free to deform such as cradled panel paintings or furniture, how damage and propagation are related to the acoustic signals which are measured, and ultimately, how the results will lead to recommendations for climate control for historic furniture or wood panel paintings. I look forward to hearing about his research in the next years.
https://aics47thannualmeeting2019.sched.com/event/Iumq/research-technical-studies-acoustic-emission-analysis-of-humidity-induced-damage-to-model-wood-structures
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