GB/T 45159.4-2025 Active

This document describes a dynamic stiffness method for measuring the dynamic complex moduli (Young's modulus, shear modulus, and bulk modulus, as well as loss factors in tensile, shear, and compression strain states) of viscoelastic materials, suitable for polymer materials (such as rubber, viscous polymers, and hard plastics) over a wide frequency and temperature range. The method obtains the dynamic excitation applied to the specimen and the strain response generated by the specimen through sensor signals. These signals are proportional to the dynamic force applied to the specimen and the strain generated by the specimen. The measurement frequency range depends on the specimen size, measurement accuracy, the stiffness of the exciter and the specimen, as well as the resonance characteristics of the test fixture. This document is applicable to any measurement conditions where a small dynamic strain (linear behavior) is superimposed on a static preload (including cases where the static load deformation curve exhibits non-linearity). Under given pre-compression conditions, the relationship between the moduli is unique.