Simple optical strain measurement on 96 test stations

Wismar University conducts intensive materials research and development work for polymer plastics, especially in fields involving the functionalization of thermoplastics and WPC (wood plastic composites) development. A multi-station creep testing system that sets new standards in both specimen preparation and in test data determination and management was developed for Wismar University in order to generate a large volume of reliable measured data quickly and easily.

The polymer plastic specimens with a cross section of 10x4 mm are subjected to a 4-point flexure test on each of the 96 stations in a standard climate. The flexural load is applied directly by means of dead weights. Despite the numerous testing stations, the strain measurement is simple to perform thanks to the non-contact video extensometers and the lack of complex specimen preparation. The reason for this is that the individual flexure benches, and not the specimens, are provided with measurement marks in this system.  The tests are performed in accordance with the ISO 899-2 standard.

Another advantage of this system is the so-called multiplex process, in which the strain values are determined with several fixed cameras from the rear of the test stand and administered by a master PC. Inaccuracies caused by movable cameras can thereby be ruled out.  Measurement from the rear ensures simple reloading of individual stations with new specimens without disturbing the tests on other stations.  The desired test evaluations can then be performed centrally on the master PC using the proven testing software testXpert II.

More information about creep testing.