Development of flexible active mechanical metamaterials for autonomous morphing and shape adaptation

Scope

The target is to develop flexible mechanical metamaterials as mechanical springs with a "near-zero stiffness" (in the range of interest) for active membrane actuators and electrostatic bellow muscle (EMB). By using topology optimization, we aim to leverage the advantages of both metamaterials and electroactive components. Among the activities are topological optimization of mechanical metamaterials to obtain architecture/programmed response, studies on additive manufacturing techniques, impact of defects and other imperfections on the component's structural integrity, and simulations of the response of the active mechanical metamaterials.

Expected Outcomes

The result is the prototype of an active, reliable, flexible, lightweight metamaterial with soft embedded actuators that can yield complex shape-morphing.

The activity, which began in December 2024, is currently in Phase 1, focusing on three key objectives:

Material Selection: Identifying the most suitable material by balancing rigidity and flexibility. A literature review has been completed, and initial test samples—comprising TPU and other materials—are currently under evaluation.
Designing Possible Connection with the EBM: Various fabrication techniques and geometries are being explored to gain a deeper understanding of the overall architecture of the EBM.
Simulation of Initial Geometries: Conducting simulations on selected simple unit cells to assess force magnitude, displacement, and mechanical behavior (e.g., quasi-zero stiffness). Cosine beam is currently being simulated as the first trial and it seems to provide qualitatively the desired response.

As the project transitions into Phase 2, these activities will be expanded by developing larger and more complex metamaterials tailored to the required force and displacement ranges (i.e. quantitative analyses).

Publications and Patents

Personnel

Reference person: Pasquale Gallo
DII members: Giacomo Moretti, Matteo Benedetti, Hadi Taghvaei (PhD student)
External collaborators: Katia Bertoldi (Harvard University), Humberto Almeida (LUT and Aalto University)

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