For biaxial tensile tests a laser extensometer has been developed. Two laser extensometers of the type P100 are combined to measure strain in X- and Y-direction. The strain measured in X- and Y-direction can be stored on the computer for the laser extensometers and they are available as a control signal for the testing environment. 

The scanning sequence of the two systems is synchronised to each other. A single receiver with special optical components is used for both scanners. The scanners and the receiver are mounted on a vertical rod. The scanning location is adjustable by rotating the scanners. The working distance is adjusted using linear positioning systems.

Load-Strain Diagram for X- and Y-strain

In addition the load signals (X & Y) are recorded. The X-Y-position of the specimen's center is available for controlling the test stand.The diagram on the right hand side shows the load-strain signals for the X- and Y-axis. The red curves represent the measurements of the laser extensometer, the blue curves repre-sent mechanical strain sensors.Load-Strain Diagram for X- and Y-strain, laser and mechancial