Non-contact method for measurement of strain profile at a location interposed within a soft deformable object with dynamic evolution of the strain under dynamic loading or fracture of the object

A non-invasive method for estimation of strain profile and dynamic evolution of the strain at a location interposed inside a block of material, comprising:

• preparing a first block of crosslinked material by crosslinking a first predetermined quantity of a pre-polymer solution containing a monomer, a crosslinking agent, an initiator, and a promoter in a solvent at a known stoichiometric weight ratio, the crosslinking reaction being carried out inside a mold at room temperature or at an elevated temperature, such that the first block of the crosslinked material has one of a flat face and a desired curvature;
• transferring a tracer grid comprising of tracer particles in a form of lines or dots onto a surface of the first block by direct writing or transferring;
• preparing a second block of crosslinked material by crosslinking the pre-polymer solution containing a monomer, a crosslinking agent, an initiator, and a promoter in a solvent at a known stoichiometric weight ratio on the surface of the first block to form a composite block comprising the second block of crosslinked material in contact with the surface of the first block and a plane containing the tracer particles is embedded between the first block and the second block;
• visualizing and recording displacement of the tracer grid when the composite block is subjected to normal shear, torsional loading, or fracture by insertion of an object therein;
• and
• estimating a strain field from the displacement of the tracer grid.