At the in-house Trade Fair for Testing Technologies (held from October 11-14 in Ulm), the materials testing machine manufacturer Zwick in Ulm introduced a cornering fatigue testing machine with a new design. This machine is equipped with testControl, the measurement and control electronics from Zwick, and fully meets the demands of a state-of-the-art testing system. In line with the extension of the device, further enhancements were made to the testing process and the handling of the machine.
The cornering fatigue test according to DIN 50113 serves for the determination of the fatigue strength under bending stress of round specimens by applying a defined rotational bending load. The specimen is subjected to alternating loads. As the highest stresses occur on the surface of the specimen, the state of the surface is of particular importance in this test.
The measurement and control electronics play a key role: from the processing of the physical measurement signals for the subsequent data processing using the relevant programs over control of the test program run up to regulation of the drive – all these activities are done fully automatically and in real time. The benefit for the user is high process security and assured standards-compliant testing.
Figure 1. Cornering fatigue test.
The proprietary Zwick testing software testXpert® supports the users in all their activities: the user needs only enter the test job and start the testing, testXpert® outputs the results in the desired form. A special test program is available for the cornering fatigue test. For example, the software supports variable setting of the rotational speed. The speed regulation feature ensures rpms.
A further benefit is the variable setting of the bending moment using weights. The bending moment thus remains constant over the entire length of the specimen. The self-centering specimen clamping feature avoids errors due to poor linearity and the weight force of the clamping itself.
A safeguard with monitoring switch ensures operator safety. Add-ons for temperature measurement and the determination of the load weight per load cell are available on request.