As part of the BAANG project the internship of Ondřej Červinek served to acquire new knowledge in the field of computational modeling research of superelastic materials at the Institute of Lightweight Design and Structural Biomechanics of TU Wien. What new development in the project did Ondrej achieve from October to mid-December, when he stayed in Vienna?
Photo: Jan Prokopius, BUT
“My work built on the experiences from the previous part of my stay, which took place in the first half of 2023. The first steps included processing the results of the experimental measurements from materials research carried out at my home workplace. This included the analyzing unprocessed nitinol powder, measuring the dimensions of a series of single tracks, measuring the porosity and dimensional stability of thin walls and bulk samples, EDS analysis, DSC analysis and determining key parameters of cyclic compressive loading of cylindrical samples,” says Ondřej Červinek.
With the help of the evaluation carried out, it was possible to identify the qualitative properties of individual sets of process parameters to produce samples, and thus determine potentially advantageous configurations for the design of complex metamaterials. In general, the determined configuration of process parameters was required to minimize porosity, cracks and other defects, high dimensional accuracy, high transformation strain values and low residual strains. These properties are highly desirable for the development of metamaterials that enable efficient morphing, which is crucial for achieving the goals of the BAANG project.
“Once the samples with the best ratio of key properties had been identified, the input parameters of the material model for computational modeling were determined based on their cyclic load behavior. This was the part where the experience from the first half of my stay was particularly important. These parameters were determined for both the superelastic and the shape memory definition of the material model. In addition, the parameters for the one-way piecewise plasticity loading curve were also determined. All definitions of the material model were verified with the cyclic loading experiment of the specimens with excellent results. Subsequently, the definitions of the material model were applied in load simulations of complex metamaterials, also with very good results,” adds Červinek.
