Resumo:
Metamaterials (MMs) are artificial structures designed to exhibit unique properties not available in nature. The aim of this study is to develop a chiral mechanical metamaterial (MM) to attenuate vibrations in a bicycle seatpost, using computational modeling, fabrication of a prototype by 3D printing, and life cycle assessment (LCA). Two types of seatposts damping systems were examined. The first one corresponds to a conventional model (CC) with integrated damping, already available on the market. The second one refers to a MM design (CMM), developed with the same functionality. Additionally, an optimized model of the CMM (CMMot) was proposed with a reduction in the total mass of the component, in order to evaluate any advantages associated with the reduced use of material and energy for manufacturing. The geometry of the CMM has a central arch-type unit cell (CACs), i.e., it has straight sections at the ends and concave curvature in the intermediate section, allowing the concentration of deformation in this region. Through computer modeling, the three geometries were designed, and then the CMM was constructed using 3D printing in selective laser melting (SLM) with 316L steel. Next, a comparative LCA was performed on the inputs derived from the manufacturing processes of the seatposts. The results of the numerical simulation indicated that, while the CC obtained a maximum displacement in Z of 20.47 mm, the CMM responded with a significantly lower value of 2.55×10-4 mm and the CMMot of 2.41×10-4 mm, indicating the promising potential of MMs in vibration mitigation. With regard to LCA, CMMot performed better than the original CMM, with reductions of approximately 32% in all impact categories evaluated. However, CC still has a lower total environmental impact, even with the use of renewable energy sources. The negative effects of CMM are mainly related to the electricity consumed during additive manufacturing. From an environmental and structural point of view, CMM represents a significant technical advance, but it still depends on improvements in the process to increase its sustainable viability. The research contributes to the literature by addressing the integration between MMs and LCA, an area that has been little explored, and reinforces the need for future studies involving a cradle-to-grave approach, experimental validations, and production scaling strategies.
