Test Method Summary
ASTM D7028 has become a widely used test standard in many companies due to lightweighting initiatives, especially in the automotive and aerospace industries, that have greatly increased the use of composites. This test standard determines the glass transition temperature (Tg) of polymer matrix composites containing continuous, oriented, high-modulus fibers. Rectangular specimen responses are measured while being heated at 5 C/min (9 F/min) under flexural oscillation at 1 Hz in the DMA mode. This resulting DMA Tg is an excellent indicator of the composite’s upper limit application temperature, and is also useful for quality control of composite materials.
NOTE: Data accuracy is particularly critical with composites as failures can occur even when loads are within design parameters. Such failures are often attributable to the time-dependent phenomena known as creep. Accurate glass transition temperatures are best achieved using representative specimen sizes and a High-Force DMA test system which has no mechanical resonances, has the ability to measure across extreme dynamic range amplitudes, and has superior control of dynamic amplitude.
Solutions for ASTM D7028 typically include these types of components:
Load Frame Options
Both the MTS Acumen® and the MTS Landmark® test systems are ideal for determining the glass transition temperature (Tg) of polymer matrix composites per ASTM D7028. They offer a variety of force capacities and deliver up to 100 Hz (covering three decades) of precise, frequency controlled test protocols to accommodate a wide variety of DMA Tg, DMA and other fatigue testing needs. The compact MTS Acumen systems’ electrodynamic actuation consumes less energy than other technologies, and provides a clean, quiet, and cost-effective system operation. The MTS Landmark 100 Hz Elastomer Test System is a tabletop system that features MTS servohydraulic actuation technology, and is the preferred test system when testing requirements demand higher force capacities.
For other options related to this standard, please download the application test method tech note on this page.