Developing advanced metamaterials with improved vibration fatigue resistance

The demand for lightweight and multifunctional materials with improved properties in engineering and other applications has risen due to a lack of resources, rising raw material costs and stricter sustainable development policies. Some of the most promising materials that have shown promise in meeting these demands are cellular materials with the internal cellular structure. They are artificially engineered materials with complicated structures that give them novel properties, such as high stiffness-to-weight ratios, improved fracture resistance, improved damage tolerance, and enhanced specific energy absorption. Combining different base materials with purposely designed cellular structures of various morphologies makes it possible to achieve a unique and attractive combination of mechanical and thermal properties. These properties can be tailored through careful design of the cellular structure that has properties not found in naturally occurring materials. The need for strong, lightweight, and rigid materials has grown in recent years as the demands for structural performance have increased. This has led to the development of advanced materials with unique microstructures, heterogeneities, or hybrid compositions to meet these demands. The auxetic cellular structure is a type of metamaterial that exhibits a negative Poisson's ratio, which is a different behaviour compared to conventional materials. Such behaviour is made possible by carefully designing 2D or 3D hinge- or sheet-like cellular skeletons with predefined geometry. Recently, more attention has been devoted to research triply periodic minimal surface structures (TPMS) metamaterials. TPMS metamaterials are a class of mathematically designed structures defined by their minimal surface area and periodicity in three dimensions. The geometries and mechanical properties of most cellular and especially auxetic and TPMS metamaterials are not yet clearly characterised and determined. At the same time, many influencing parameters on the mechanical response, especially in fatigue loading, must be defined. The main objective of the proposed research project is to develop advanced metamaterials with improved vibration fatigue resistance. The research work will include extensive experimental testing under quasi-static and cyclic dynamic loading conditions. The experimental results will provide necessary information to better understand the complex behaviour of metamaterials when subjected to various mechanical loading conditions and help identify the most appropriate geometrical and material parameters combinations of cellular structures to achieve desired behaviour. An extensive experimental testing of auxetic and TPMS metamaterials will be complemented by the advanced modelling and computer simulations with purpose of full characterisation of their mechanical properties, necessary for their proper implementation in design of new engineering and other applications. Despite the progress that has been made in the development of metamaterials, there are still challenges in creating new metamaterials that have both high load-bearing capacity and excellent fatigue resistance. Metamaterials with improved mechanical properties will be developed for various applications using parametric optimisation, including a combination of computer-aided design and computer simulations. This research project aims to address this challenge by designing and analysing 2D and 3D metamaterials that have great potential in various applications. The results of this project will significantly contribute to understanding the geometric and mechanical characteristics and fatigue behaviour of advanced metamaterials. It is worth mentioning that the study of metamaterials fatigue behaviour is still in its early stages and requires further research.