Mechanical Models

Using Mechanical Tests

We use mechanical tests on laboratory samples to investigate properties of the components used in the construction of panel paintings. By doing so, we are able to examine the mechanisms that give rise to the initiation and propagation of cracks such as those found in the portrait set at Knole.

Tensile Testing

One particular focus of our tests is to examine the tensile strength of components such as the glue used to join wooden boards.

Tensile test of rabbit skin glue free film. Overall view.
Tensile test of rabbit skin glue free film. Overall view.
Tensile test of rabbit skin glue free film. During damage.
Tensile test of rabbit skin glue free film. During damage.
Tensile test of rabbit skin glue free film. After the test.
Tensile test of rabbit skin glue free film. After the test.

Testing Bonded Layers

Another focus of our tests is on examining the interfaces between bonded layers. Double cantilever beam (DCB) tests are common experiments in the field of adhesive fracture mechanics, and we make use to investigate this aspect of the construction of the paintings.

Double cantilever beam set up with oak wood and rabbit sking glue joint. Test perfomed at Imperial College by Cecilia Gauvin.
Double cantilever beam set up with oak wood and rabbit sking glue joint. Test perfomed at Imperial College by Cecilia Gauvin.
Crack in double cantilever beam sample (oak wood and rabbit sking glue joint). View from the Microscope.
Crack in double cantilever beam sample (oak wood and rabbit sking glue joint). View from the Microscope.

The Environmental Chamber

Given our focus on the impact of environmental conditions, it is important that we can perform our laboratory tests in controlled environmental conditions of temperature and relative humidity. To achieve this, we have included the design and build of a bespoke environmental chamber to support our work.

Design outline for the IMPASTOW environmental chamber
Design outline for the IMPASTOW environmental chamber
From design to production - a bespoke environmental chamber for use in performing laboratory tests
From design to production – a bespoke environmental chamber for use in performing laboratory tests