Stratasys 3D Printing: Photoelasticity with PolyJet

Photoelasticity with PolyJet

Photoelasticity is a visual method to determine the stress distribution of a part geometry.  Unlike analytical methods of stress calculations, photoelasticity gives a fairly accurate picture of stress distribution around any imperfections in the actual geometry.  This method can be an important tool for identifying critical stress concentration in irregular geometries.

The principal of photoelasticity is based on rays of light passing through certain transparent materials with two refractive indices to create a phenomenon of an isochromatic image known as ‘Birefringence’ or double refraction.  This phenomenon is similar to light separated by an optical prism or crystal.

While the definition above may sound complex, the practical implementation is much simpler.  Start with a clear Polyjet part; the 3 x 3 inch part shown below is made with VeroClear RGD 810 material.  Next, add a Linear Polarized laminate sheet on each side and some pressure to create stress on the part.  This will produce the isochromatic image shown below.  Note the laminate is Polarized in a linear direction, therefore for best results position the laminate pieces adjacent or perpendicular to each other.

Mark Abshire
Application Engineer, Additive Manufacturing
Computer Aided Technology