What is ISO 6721-8 - Longitudinal and shear vibration of plastic about?
ISO 6721-8 is the eighth part of the ISO 6721 multi-series on dynamic mechanical properties of plastic. ISO 6721-8 describes an ultrasonic wave propagation method for determining the storage components of the longitudinal complex modulus L* and the shear complex modulus G* of polymers at discrete frequencies typically in the range 0,5 MHz to 5 MHz the method is suitable for measuring materials with storage moduli in the range 0,01 GPa to 200 GPa and with loss factors below 0,1 at around 1 MHz. With materials that have a higher loss, significant errors in velocity measurement are introduced through waveform distortion and can only be reduced using procedures that are outside the scope of ISO 6721-8.
Note: The method allows measurements to be made on small specimens, typically 50 mm × 20 mm × 5 mm, or small regions of larger specimens or sheets. It is therefore possible to obtain information on the homogeneity or anisotropy of modulus in a specimen.
Who is ISO 6721-8 - Longitudinal and shear vibration of plastic for?
ISO 6721-8 on longitudinal and shear vibration of plastic is useful for:
- Plastic manufacturing industries
- Plastic testing laboratories
Why should you use ISO 6721-8 - Longitudinal and shear vibration of plastic?
ISO 6721-8 discusses the terms and definitions, principles, testing devices (which involves apparatus, transducers, transit-time measurement equipment, and temperature measurement and control), a procedure that involves test atmosphere, measuring the specimen dimension, performing the test, varying the temperature.
ISO 6721-8 describes the expression of results that involves symbols, determination of the longitudinal wave velocity vL, determination of the transverse wave velocity vT, calculation of dynamic properties, and influence of material anisotropy.
ISO 6721-8 provides you with comprehensive information useful throughout the process of measurement.
So, ISO 6721-8 helps to determine the accurate value of longitudinal and shear vibration from the dynamic mechanical properties of plastic.
What’s changed since the last update?
BS ISO 6721-8:2019 supersedes BS ISO 6721‑8:1997 which has been withdrawn. BS ISO 6721-8:2019 includes some technical changes with respect to BS ISO 6721‑8:1997. These include:
- The document has been revised editorially
- Normative references have been changed to undated.