Speaker
Description
Funding Acknowledgement: funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Projektnummer 543895078
Metamaterials are artificially designed structures that exhibit tailored mechanical properties. These properties result primarily from their underlying small-scale architecture and can therefore be optimised by adapting this structure. Owing to this, metamaterials are suitable for a wide range of applications, such as energy absorption, sound isolation, or seismic protection [1]. The future aim is to develop a three-dimensional metamaterial in the form of a slender, chiral lattice with rigid inclusions with superior properties reminiscent of the fundamental work of [2]. As a first step the mechanical behaviour the two-dimensional projection of the underlying structure is investigated herein. In a single unit, square shaped rigid inclusions are linked by simply supported struts. This unit of the metamaterial is investigated using a methodological three-tone: 3D printing, compression tests, and simulation. The methods are used iteratively to carry out parameter studies in order to optimise the model. A key focus of the talk is on designing the CAD model with regard to fabricate the unit cell using extrusion-based additive manufacturing technology, so-called 3D printing. Further tailoring of detailed structures such as hinges is achieved by tuning the printing parameters for fused filament fabrication. This tailoring process is presented together with experimental test results. The experimental tests are complemented by a theoretical framework for the simulation. This is based on the general theory of elastic stability [3]. The buckling and post-buckling behaviour is determined by minimising the total potential energy with respect to the generalized coordinates. The equations are solved with the in-house developed, open-source Python-based module 'pyfurc' [4]. Results of the first pilot studies will be presented which exhibit the desired rotation of the rigid inclusions under a compressive load.
References:
[1] J. Liu et al. “A Review of Acoustic Metamaterials and Phononic Crystals”. In: Crystals 10.4 (Apr.2020), p. 305. issn: 2073-4352. doi: 10.3390/cryst10040305.
[2] J. Li et al. “Observation of Squeeze–Twist Coupling in a Chiral 3D Isotropic Lattice”. In: physica status solidi (b) 257.10 (2020), p. 1900140. issn: 1521-3951.
doi: 10.1002/pssb.201900140.
[3] J. M. T. Thompson et al. A general theory of elastic stability. John Wiley \& Sons, 1973.
[4] Klunkean. pyfurc - Auto-07P made accessible through python.
URL: https://github.com/klunkean/pyfurc.
