Bio-inspired irregular lattices as enhanced lightweight dampening system

Vibration dampers play a crucial role in mitigating high-vibration amplitudes in engineering structures. However, in applications where lightweight and cost-effectiveness are paramount, the use of heavy and expensive dampers as additional components appears counterintuitive. Implementing a low-weight high-damping mechanism in a system will not only help to reduce the amplitude of vibration but also avoid resonance. This paper investigates irregular lattice configurations inspired by diatoms, radiolaria, and glass sponges to serve as lightweight, high-stiffness, and damping mechanisms in a frequency-dependent manner. Lattices featuring regular and irregular shapes with identical weights are designed and manufactured with the selective laser sintering technique using polyamide 12 (PA12) as the material. Finite element analyses and vibration tests in the range of 0–50 Hz are conducted to obtain the measured and numerical damping coefficient, stiffness, and loss factor of each lattice. Subsequently, the results are analysed and compared across different lattice configurations. The comprehensive findings indicate that lattices with higher structural irregularity, quantified using the proposed geometric irregularity index I irr , exhibit improved damping behaviour and stiffness across all studied frequencies. Furthermore, the bio-inspired irregular lattices exhibit a more intricate and frequency-sensitive response while regular lattices exhibit a smoother, monotonous decline in the loss factor and damping coefficient with increasing frequency. In conclusion, this research indicates that incorporating irregular characteristics has a high potential to manipulate the damping behaviour of lightweight lattice structures.