TWI is now offering true stress - true strain tensile testing to failure at a range of temperatures up to 300°C. The developed test method uses digital image correlation (DIC) to extract the geometrical parameters required to calculate the true stress - true strain response beyond necking. These parameters include instantaneous extension, necking radii and cross-sectional area all the way to failure.
In tensile testing, at the onset of necking, the stress-state changes from uniaxial tension to a complex triaxial stress-state. This is accounted for using already developed corrections such as the ‘Bridgman Method’, which enables sufficiently accurate stress-strain data to be generated for this region of the test.
This data is useful for finite element modelling of high-strain applications, which are frequently encountered in the oil and gas, power and aerospace industries.
For more information on this testing method, please contact us.