The various parts of ISO 6721 specify methods for the determination of the dynamic mechanical properties of
rigid plastics within the region of linear viscoelastic behaviour. This part of ISO 6721 is an introductory section
which includes the definitions and all aspects that are common to the individual test methods described in the
subsequent parts.
Different deformation modes may produce results that are not directly comparable. For example, tensile
vibration results in a stress which is uniform across the whole thickness of the specimen, whereas flexural
measurements are influenced preferentially by the properties of the surface regions of the specimen.
Values derived from flexural-test data will be comparable to those derived from tensile-test data only at strain
levels where the stress-strain relationship is linear and for specimens which have a homogeneous structure.
BS EN ISO 6721-1:2019 history
1970BS EN ISO 6721-1:2019 Plastics. Determination of dynamic mechanical properties. General principles
2011BS EN ISO 6721-1:2011 Plastics. Determination of dynamic mechanical properties. General principles