Mountable lattice metamaterials with In-situ reprogrammable stiffness

Abstract

Most materials exhibit fixed mechanical properties after fabrication, limiting their applications that require multiple or adaptable mechanical properties. Here, we propose a novel class of mountable lattice metamaterials composed of two mountable parts: a strut-part and a hole-part. The two parts can be assembled in opposite direction of deformation, leading to continuously changeable stiffness under compression. We systematically evaluate the effects of the structural angle, assembly direction, strut shape and interval, and insertion depth on the deformation and stiffness of lattice metamaterials. Results show that the assembly direction is critical for generating changeable stiffness. When the two parts are assembled in the same direction, the stiffness remains constant. Moreover, the structural angle ([Formula: see text]) significantly influences the stiffness, with an 11-fold increase observed as [Formula: see text] increases from 45° to 75°. For a given [Formula: see text], the insertion depth ([Formula: see text]) enables great in-situ tuning of stiffness after fabrication. Additionally, we construct a cellular structure with [Formula: see text] units that achieves [Formula: see text] reprogrammable stiffnesses states by discretely changing the [Formula: see text], offering theoretically infinite possibilities. This research establishes a foundation for the design and fabrication of metamaterials with intelligent and reconfigurable stiffness.

Keywords

• Lattice design
• additive manufacturing
• mountable structures
• reprogrammable stiffness
• deformation