Projects / Programmes
Development and characterisation of advanced auxetic cellular metamaterials
| Code |
Science |
Field |
Subfield |
| 2.11.02 |
Engineering sciences and technologies |
Mechanical design |
Special constructions know-how |
| Code |
Science |
Field |
| 2.03 |
Engineering and Technology |
Mechanical engineering |
multifunctional materials, cellular material, auxetic materials, metamaterials, mechanical characterisation, computational simulations, high strain rate loading
Researchers (1)
| no. |
Code |
Name and surname |
Research area |
Role |
Period |
No. of publicationsNo. of publications |
| 1. |
38219 |
PhD Nejc Novak |
Mechanical design |
Head |
2020 - 2022 |
194 |
Organisations (1)
Abstract
Cellular structures have been increasingly used in modern engineering applications over the past decade due to their attractive combination of mechanical and thermal properties. Recent advances in additive manufacturing technologies enable the fabrication of parts with complex internal cellular structure, which is commonly adjusted to application needs. A special type of complex cellular structures are auxetic cellular structures that exhibit a negative Poisson’s ratio. The auxetic cellular structures has more or less complex two- or three-dimensional geometrical structure, which allows them to deform in a particular way and thus experience large volume changes under loading. They tend to expand in the lateral direction when subjected to longitudinal tensile loading and vice versa in case of the compressive loading. This behaviour provides for some extraordinary mechanical properties, which makes them very suitable for some specific applications. The geometry of most cellular and especially auxetic metamaterials (morphology and topology) and mechanical behaviour are not yet well characterised and many influencing parameters have yet to be determined, especially when such martials sustain dynamic loading conditions. The purpose of the proposed research is to develop new, topologically optimised three-dimensional cellular and especially auxetic structures with uniform and graded porosity with follow-on comprehensive experimental and computational characterisation of their mechanical behaviour under various loading conditions (including shear loading). An extensive experimental testing programme of newly developed cellular and auxetic specimens will be complemented by the advanced finite element modelling and computer simulations with purpose of full characterisation of their mechanical properties, necessary for their proper implementation in design of ne engineering and other applications. The characterisation will consider behaviour of cellular metamaterials at quasi-static, low and high-speed dynamic loading conditions. A comprehensive computational and experimental study of forbidden frequency band gaps of selected cellular geometries is also envisaged. The experimental testing will be supported by a non-destructive infrared thermography technique enabling excellent visualization and consequent analysis of local deformation process. This will provide necessary information to better understand the complex deformation mechanism of two- and three-dimensional auxetic structures when subjected to various mechanical loading conditions and help to identify the most appropriate geometrical and material parameters combinations of cellular structures to achieve desired behaviour. Newly developed auxetic cellular geometries will be further used to design auxetic composites. A special crash absorber with optimised auxetic structure filled with aluminium foam will be developed and tested as the application showcase to demonstrate enormous enhancement in energy absorption capabilities of such novel crash absorber. The auxetic sheet composites fabricated with explosion welding will also be investigated following the same principles. In combination with parametric computational simulations and topological optimisation procedures, the results of this research will provide significant advances in state-of-the-art knowledge for efficient application of cellular metamaterials and composites in future engineering and other applications.
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