Development of a cellular composite with the ability to transform cells by a selected activation mechanism

When developing new composite structures, the vast majority of current research is limited to certain permanent, fixed properties of the material. This project proposal therefore focuses on the less researched field of variable properties of materials, where the properties of the product can be adjusted and changed both in terms of shape and mechanical characteristics. is the project is about a comprehensive research and development of a multifunctional protective structure with the ability to transform internal cells. Such a structure will have some unique mechanical properties that cannot be achieved with any other known material. Thoughts on the creation and production of such a material began only recently with the development of layered additive technologies that enable very good reproducibility in 3D printing of complex shapes. The purpose of the proposed postdoctoral research project is the development of completely new protective structures on digital twins and then the physical production of a panel from such a structure. This will be followed by a comprehensive testing program from static to dynamic and shock tests of the new structures. The objective is to design such a structure, in which the intermediate changing properties of the material would also be used for the self-renewing ability of regeneration after possible damage. This also means a direction towards the development of sustainable products, which is also the recommendation and direction of the EU in the directive COM (2008) 0397. Changing the structure's geometric/mechanical properties will be achieved with a short activation heating of the wires, with temperatures around 80 ºC. Wires made of NiTinol and inserted into the polymer matrix will enable the transformation of the cells in such a way that, as a structural unit, when deformed, it will enable the achievement of a positive or even a negative Poisson's ratio. In the latter case, this means that such structures react differently than most metallic and non-metallic materials, e.g. when stretched they expand and conversely when compressed they shrink. All these properties of newly developed structures with the ability to transform cells will be checked on the modern experimental equipment that we have at the KSERV department. The developed multifunctional protective cellular structure with the ability to transform cells will have great application potential in high value-added products and will enable: i.) passive responsiveness, i.e. it reacts when influenced - useful e.g. in the case of protective equipment or even ii.) active responsiveness, i.e., the possibility of subsequent programmed changes of various properties. For example, by temperature activation of the NiTinol wire armature, we change the global geometry of the protective panel from flat to cylindrical.