Manufacturing of a quasi-zero-stiffness resonator: from additive manufacturing towards injection moulding

Locally resonant metamaterials enable combining lightweight design with favora-ble noise and vibration properties, allowing structures to meet ever tighter engineering re-quirements. Their superior vibration attenuation in targeted frequency zones emerges form the sub-wavelength addition of resonant elements to a host structure. Given their strong po-tential, numerous academic demonstrators have been realized. However, to advance these metamaterials to an industrially applicable engineering solution, both the manufacturing ap-proaches and the tunable frequency range still form major hurdles. To date, the majority of locally resonant metamaterials are realized via additive manufacturing. While this technique can in particular cope with intricate metamaterial designs, it is not well-suited for cost-effective mass-manufacturing. To overcome this hurdle, injection moulding is recently ex-plored and gaining increased attention to mass-manufacture metamaterials. This work inves-tigates the potential of injection moulding to mass-manufacture a recently introduced quasi-zero-stiffness resonator, promising lower frequencies of vibration attenuation and a broaden-ing of the frequency zone of attenuation due to the inherent nonlinear stiffness of the resona-tor. This resonant element consists of a dual-spring mechanism and an assembled buckled beam. First, the dual-spring mechanism is tailored to meet injection moulding manufacturing design guidelines after which the corresponding mould is designed. To allow design adapta-tion, the beam is 3D printed and the influence of the beam dimensions on the resonator per-formance is experimentally assessed together with the repeatability of the assembled system.