Biaxial Mooney-Rivlin Coefficient of Silicone Sheet by Additive Manufacturing

Abstract

This study evaluates the biaxial Mooney-Rivlin coefficient for silicone sheets made by additive manufacturing (AM) for custom wearable assistive devices and soft robotics. The extrusion-based layer-by-layer technique is applied for AM of moisture cured silicone sheets. A progressive cavity pump controls the precise, continuous flow of high viscosity silicone for low void AM of the cruciform shaped specimen. A biaxial tensile test apparatus with four independent linear actuators was built for testing the cruciform specimens. Digital Image Correlation method was utilized to calculate the distribution of strain. This study show the value of the biaxial Mooney-Rivlin coefficient for the AM silicone sheet is independent of the thickness and in the range of 114.7 kPa to 132.1 kPa for C10 and –17.9 kPa to –9.04 kPa for C01. The geometry of the specimen is shown to affect the biaxial quality of the specimen.