BS ISO 18437-4:2008

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Equipment
   5.1 Hardware
   5.2 Set-up
6 Recommended set-up for applying the different types
   of strain to the test piece and calculation of
   quotients, alpha[E,G,K]
   6.1 Choosing test piece size
   6.2 Rigid plastics
   6.3 Rubbery materials
   6.4 Viscous materials
   6.5 Bulk modulus of all materials
7 Test pieces
   7.1 Choosing the shape and size of the test piece
   7.2 Instructions for manufacturing and preparing test
        pieces
8 Conditioning
   8.1 Storage
   8.2 Temperature
   8.3 Mechanical conditioning
   8.4 Humidity conditioning
   8.5 Measurement conditioning
9 Main error source
10 Measurement results and processing
   10.1 Frequency-temperature superposition
   10.2 Data presentation
   10.3 Test report
Bibliography

Describes a direct method for measuring the complex dynamic moduli of elasticity (the Young, shear and bulk moduli, and their respective loss factors corresponding to the tensile, shear and all compressive strains) for polymeric (rubbery and viscous polymers, as well as rigid plastics) materials over a wide frequency and temperature range.

This part of ISO18437 specifies a direct method for measuring the complex dynamic moduli of elasticity (the Young, shear and bulk moduli, and their respective loss factors corresponding to the tensile, shear and all compressive strains) for polymeric (rubbery and viscous polymers, as well as rigid plastics) materials over a wide frequency and temperature range. Measurements are performed by the dynamic stiffness method, which uses electric signals from sensors attached to a test piece. These signals are proportional to the dynamic forces acting on the test piece and the strains in the test piece due to the effect of these forces.

The measurement frequency range is determined by the size of test piece, the accuracy required on the dynamic modulus measurements, the relationship between the stiffness of the oscillation generator and the stiffness of the test piece, and by the resonance characteristics of the test fixture used.

The method presented in this part of ISO18437 allows measurement under any static pre-load allowed for the test piece (including the test piece having the non-linear characteristics under different static loads), but under small dynamic (acoustic) strains, i.e., in limits where the linear properties of the test piece are not distorted. Depending on the pre-load conditions, the relation between the moduli is unique.