Mechanical Characterization of Materials is undertaking laboratory research together with in-situ testing to more precisely identify the conditions under which irreversible damage occurs in cultural heritage materials as a result of climatic agents of deterioration. Better understanding of these conditions can help collections care professionals determine whether permanent damage occurs in susceptible materials exposed to the broader acceptable climatic ranges currently under consideration by the conservation field and to understand the rate and degree of fluctuation these materials can withstand.
There is already a substantial amount of data from the collections care field that supports a shift to less stringent climate requirements for collections materials. However, it is often pointed out that most of these data have been obtained in a laboratory environment by testing artificially aged samples or simplified mock-ups of objects. These laboratory samples do not represent accurately enough the changes that naturally aged objects undergo.
In general, cultural heritage objects are more complex than mock-ups as they combine different materials in a specific construction. The existing general model of damage caused by climate fluctuations fails to consider irregularities and flaws in real objects. Simulation models using finite element modeling (FEM) address these deficiencies but lack data about the distribution of stress concentration factors in real objects.
Providing an evidence-base for the effect of environmental conditions on historical materials has long been a challenge for the conservation field, due to both the inherent complexity of the materials and uncertainty in the mechanisms at play in environment-induced change. Understanding the mechanical properties of cultural heritage materials is a fundamental aspect of establishing the critical environmental conditions which lead to irreversible change.
In response to the lack of research on historical materials in real-life conditions, Materials Characterization Research is undertaking research on naturally aged cultural heritage materials using innovative research techniques. The project focusses on two material groups that are found extensively in historical collections and which are perceived to be some of the most vulnerable to climatic agents of deterioration: wood and paint.
Mechanical Properties of Paints: researching the effects of ageing on the mechanical properties of paints by subjecting samples of naturally aged materials to micro- and nano-indentation technology.
Acoustic Emission Testing on Wooden Materials: using this nondestructive method for the direct tracing of physical change in historical objects.
By obtaining the distribution in mechanical properties of artists' materials of variable age, our understanding of the properties, structures and damage mechanisms of these materials will be improved. This will help the further refinement of algorithms used in modeling, improving the accuracy of numerical modelling predictions.
Page updated: June 2017