Zwick supplies biaxial testing system to Karlsruhe Institute of Technology (KIT)

The most frequent type of material characterization is based on results from single-axis tensile tests. Characterization of many metallic and polymer-based materials requires investigation of material behavior under single and multi-axial stress and deformation conditions. For investigations of this type the Department of Continuum Mechanics at the Institute of Engineering Mechanics (Professor Böhlke) at KIT employs a Zwick biaxial testing machine.
Investigations at the Department focus on fiber-reinforced lightweight materials and metallic materials. The investigation of mechanical behavior involving multiaxial loads and field measurement of displacements is important for the understanding of material and structure behavior, particularly for the description of modern long-fiber-reinforced materials.

4x 150kN load frames from the table-top testing machine range, positioned horizontally on their sides, are located at 90° to each other on a newly developed load frame. The upper and lower central free areas of 400 x 400 mm in the special load frame allow specimen strain to be recorded from above and below using an optical strain-measurement system.

A Zwick videoXtens extensometer is used in this instance; it outputs six analog strain-signals which are used for center-point and strain control. To enable separate control of all test axes, testXpert II testing software is used with a Master test program. In this case, use is made of the graphic multiaxial sequence editor for four axial test axes, allowing a wide range of load profiles to be simulated.