According to ASTM D638 (Standard Test Method for Tensile Properties of Plastics), I designed a tensile test (dog-bone shaped) specimen with the relevant dimensions in Autodesk Inventor.

The objective was to design outer walls around the specimen and manufacture the enclosure by rapid prototyping using PLA plastic. We would then cast elastomer materials into the enclosure's cavity to create silicone molds in the extruded cut space.

Finally, the specimen cavity will be filled by extruding composite materials and foam by additive manufacturing to create a three-layered sandwich structured specimen for tensile testing.

I chose specimen dimensions according to the ASTM document specifications. I selected minimal dimensions for the outer walls to avoid material wastage for creating the prototype using PLA material.

The images' sequence shows the design, 3D printing, and casting of silicone material into this mold. We aimed to then encapsulate liquid state materials into the cavity by a computer program controlled additive manufacturing process.