[Material Testing]
The force and strain ist measured during the defined specimen loading (tension, compression, torsion, bending). From these measures the force-strain-curve and stress-strain-curve are determined and material parameters like Young's Modulus, poisson number, elongation at strain and more complex values are calculated Different measurement systems are used :
The RTSS-Videoextensometer is suited for standardized and automatic test procedures and works as a real time strain sensor..
The Q400-Digital Image Correlation System measures spatially resolved strain values and the analysis is typicylly done in post processing because a large number of informations can be provided.
Full field strain measurement with maximal spatial resolutionThe Istra4D measurement software used in the Q400 DIC system uses a special algorithm to achieve maximum possible spatial resolution. |
RTSS videoextensometer for the determination of Young's Modulus at Tensile testsThe RTSS-Videoextensometer measures with high precision the longitudinal strain during tensile test and transfers the result to the tensile test machine. The image shows the measured stress-strain curve with the calculated Young's modulus. |
Contactless measurement of Longitudinal & Transversal strain at a tensile testThe RTSS Videoextensometer can measure the longitudinal and transversal strain with one camera. The longitudinal strain is measured through the line marker and the specimen width is measured throught the specimen border. It is possible to measure the transversal strain as an average value between the longitudinal marker (--> Posson number) or as a minumum width (necking --> R/N value). The video shows a slow tensile test with the RTSS system measuring longitudinal and transversal strain. |
Non-contact measurement of very large strains during tensile tests on rubberThe RTSS-Videoextensometer can measure strains up to 1000%. Due to the high resolution camera a high measurement accuracy is achieved over the whole range. The Video shows the measurement of a rubber specimen with max. 500% strain. |
Measuring the strain distribution during a tensile test on a CFRP sampleThe strain distribution on a CFRP specimen with hole is measured optically with a Q400 DIC ystem. The right image shows the strain after the initial failure state of the specimen. |
Strain measurement on a 3 point bending testTwo polymer plates are glued together and loaded in a 3 point bending test. The surface strain is measured with the Q400 DIC system The images show the horizontal surface strain and the strain along the vertical line 1. The left image gives compression strain (blue) and tension strain (red) as a gradient over the whole specimen. After the failure of the glue the strain distribution is separated for each plate. |
Non-contact strain measurement using DIC on a micro tensile sampleiThe strain distribution on a mikro tensile specimen is measured with Q400. The initial specimen length is 4mm, The measurement is performed with Makro lenses. Even smaller field of views can be achieved with Q400-µDIC (stereo mikroscope). The images show the specimen, the strain as overlay and the 3D result with necking. |
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Measurement of the shear strain at a shear testThe Q400 DIC system measures the shear strain and other strain components fullfield. The video shows a shear test with the measured shear strain as color overlay. |
Measurement of crack growth using DIC on a CT sampleQ400 DIC system measures the crack propagation at a CT specimen under tensile load. The video shows the measured major strain together with the recorded force.The diagram gives the crack length versus force. The yellow vectors mark the rapid crack propagation with force reduction. |