
The Rheometrics Solids Analyzer (RSA-3) employs two axially-opposed shafts to generate an oscillatory deformation and measure the resultant stress. The deformation geometry can be altered by changing the fixtures mounted on the shafts; we commonly employ either a tensile deformation (for fiber-film testing), a three-point-bend deformation (for high-modulus composites), or a shear-sandwich geometry (for soft solids or highly viscous melts). The instrument has been used to measure the viscoelastic response of materials as diverse as Kevlar-reinforced polypropylene and hydrated denture adhesives.