Nanoindentation and the dynamic characterization of viscoelastic solids

Abstract

Using a high-damping thermoplastic as a standard reference material, the purpose of this work is to compare measured values of the complex modulus as determined by dynamic nanoindentation and dynamic mechanical analysis (DMA). Experiments were performed at approximately 22 °C and seven frequencies over the range 1–50 Hz. The indentation measurements were performed using a 103 µm diameter flat punch and a newly developed test method that optimizes the accuracy and precision of the measured stiffness and damping. As determined by dynamic nanoindentation, values of the storage modulus and loss factor (tangent delta) ranged from 4.2 to 10.2 MPa, and 0.28 to 1.05, respectively. Over the range 1–25 Hz, DMA confirmed the nanoindentation results to within 15% or better. Collectively, these data and the testing methods used to generate them should help future investigators make more accurate and precise measurements of the dynamic properties of viscoelastic solids using nanoindentation.