A Frequency Response Analysis System for the Measurement of the Dynamic Mechanical Properties of Non-Metallic Materials.

摘要

A system was developed to investigate the low-strain behaviour of polymeric solids,under conditions of cyclically varying stress and strain. The properties examined are the in-phase and quadrature components of complex modulus and the associated loss angle at various frequencies. The particular advantage of this system is its ability to perform both flexural and torsional testing over a wide spectrum of material stiffness. In this report only flexural testing is described. Torque motors are sinusoidally driven to impart a known couple to a bar specimen. Strain is determined as angular movement detected by rotary transducers attached to the motor shafts. The system is controlled by a digital transfer-function analyser which provides excitation (stress) in the range 0.00001to 450Hz,relates stress to strain and then displays strain in complex form. Modulus is calculated knowing specimen dimensions,stress and complex components of strain.