A whole methodology for dynamic material characterisation has been developed at CIDAUT, based on a sample with 2 sections for the direct measurement of stress and strain values by means of strain gauges. With this method the associated problems caused by mechanical ringing in the load cell are avoided in the measurement of force.
The sample has a region, known as extensometric section, where deformation is measured. This section has the lowest area through the whole sample length, therefore strain is mainly concentrated in this part.
A second region in the sample is used to measure stress (or equivalently, the tensile force), and it is known as dynamometric section. An adequate sectional area has to be designed in this region to assess that stress level always remains under yield point throughout the test, so linear elastic material behaviour is assured in this region and stress value can be directly obtained proportionally to gauge measurement.