Films and sheets with a thickness of up to 1 mm are tested using strips or dumbbell specimens. The typical specimen shape used in ISO 527-3 and ASTM D882 is a strip specimen. This specimen shape can be easily produced using a specimen or film cutter. Dumbbell specimens are often used in quality control. For this, a direct measurement extensometer is required to measure the specimen strain directly at the specimen.
Typical test results are characteristics such as
- Yield stress
- Yield strain
- Maximum stress
- Nominal strain at break
When testing strip specimens, the strain at break results depend on the specimen shape and the type of specimen gripping used. We recommend the use of parallel clamping specimen grips. The grip inserts should be arranged so there is linear contact between the jaw and the specimen.