Deformations

Accelerations, velocitys, deformatrionsstrains and temperatures can be measured by using different measuring sensors. The planning and construction of the respective measurement chain can be carried out by SKI together with cooperation partners.

For example, during a welding test at the Institute of steel construction of the  der Leibniz University Hanover, two square plates were monitored by measurement during the welding process. With the aid of a tractor arm, the welding nozzle moved at a defined feed rate. In this respect, a fully mechanical welding process was used to achieve a very uniform weld seam quality and weld seam shape over the entire length of the seam. 

While for the right plate inductive displacmenet transducer and strain gauges were used, the left plate was coated with a high temperature resistant and stochastic pattern with an airbrush gun. The black-and-white contrast was required for the optical measuring system used to perform the 3D-deformations analysis. In addition, the welding nozzle had to be coated in order to protect the sample from welding spatter and traces of smoke. 

The following figure shows the shrinkage path in longitudinal direction of the seam as a function of time. The results of the welding simulation (HANWELD) were compared with the distance measurements of the optical sensor and LVDT. A good agreement can be seen on the basis of the progressions. 

In addition, thermocouples were arranged at points to enable comparison with the temperature field of a welding simulation after the welding test. 

Evaluation of the welding tests
Evaluation of the welding tests