[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.

Spatial strain resolution

The Istra4D measurement software used in the Q400 DIC system uses a special algorithm to achieve maximum possible spatial resolution.
Local strain gradients in static and dynamic deformations can be resolved particularly well in this way.
This video shows the tensile test of a 3D printed structure in which the strain values are measured up to the sample edges.

RTSS: Tensile test for the determination of Young's Modulus

The RTSS-Videoextensometer measures the longitudinal strain during tensile test and transfers the result to the tensile test machine.
The test software calculates from the time course of the measured force and strain and from the specimen dimensions material parameter like Young's modulus, elongation at break, etc.

The image shows the measures stress-strain curve with the calculated Young's modulus.

RTSS videoextensometer for the measurement of the Young's modulus during a tensile test

Longitudinal & Transversal strain

The 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 or as a minumum width (=necking).

The video shows a slow tensile test with the RTSS system measuring longitudinal and transversal strain.

Large strains - Tensile test on rubber

The 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 testing software calculates from the measured force and strain values material parameters like Young's modulus, elongation at break etc.
The RTSS system can be used for measurements according to ISO 37.

The Video shows the measurement of a rubber specimen with max. 500% strain.

Tensile test at CFRP

With Q400 measured strain distribution on a CFRP specimen with hole.

The right image shows the strain in the initial failure state of the specimen.

Q400 DIC measures the strain distribution at a tensile loaded CFRP specimen with hole

Bending test

Two 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.

 Q400 DIC measures the strain distribution at a bending test of glued specimen  Q400 DIC measures the strain distribution at a bending test of glued specimen

Shear test

The Q400 DIC system measures the shear strain and other strain components fullfield.

The video shows a shear test. The shear strain is shown as a color overlay.

Crack Propagation at CT Specimen

Q400 measures the crack propagation at a CT specimen under tensile load.

The video shows the major strain together with the recorded force.The diagram gives the crack length versus increasing force. The yellow vectors mark the rapid propagation with force reduction.

  Q400 DIC measures the crack propagation of a CT specimen under tensile load

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