3D printing of twisting and rotational bistable structures with tuning elements

Abstract

Three-dimensional (3D) printing is ideal for the fabrication of various customized 3D components with fine details and material-design complexities. However, most components fabricated so far have been static structures with fixed shapes and functions. Here we introduce bistability to 3D printing to realize highly-controlled, reconfigurable structures. Particularly, we demonstrate 3D printing of twisting and rotational bistable structures. To this end, we have introduced special joints to construct twisting and rotational structures without post-assembly. Bistability produces a well-defined energy diagram, which is important for precise motion control and reconfigurable structures. Therefore, these bistable structures can be useful for simplified motion control in actuators or for mechanical switches. Moreover, we demonstrate tunable bistable components exploiting shape memory polymers. We can readjust the bistability-energy diagram (barrier height, slope, displacement, symmetry) after printing and achieve tunable bistability. This tunability can significantly increase the use of bistable structures in various 3D-printed components.

Concepts and Terminologies in 4D Printing

“…Other researchers have constructed "bistable" structures that support two stable states, where reversible switching between stable configurations can be achieved under controlled mechanical actions. Bistable structures do not require additional energy to maintain their stable states and can work as mechanical switches, or to simplify actuation and motion control [17]. Other researchers have explored "auxetic structures" where the structures or materials have a negative Poisson ratio.…”

Computational Modeling of the Experimental Response of Microscale Bistable Tensegrity Structures

“…In particular, metamaterials are designed so as to obtain extraordinary mechanical properties, such as exceptional strength-to-weight and stiffness-toweight ratios, frequency bandgaps, negative overall elastic moduli, negative mass density, auxeticity, and solitary wave propagation [1] - [13]. Bistability is one of the difficult-to-find and most desired features in current studies on architected materials [14] - [19]. Tensegrity systems, pin-connected prestressed frameworks composed by bars and cables, constitute a particular structural class in that their response to statical and dynamical actions incude a rich variety of non-linear effects [20,21], [10] - [13].…”

3D and 4D printing for optics and metaphotonics

“…Three-dimensional (3D) printing is a new paradigm in the customized manufacturing of products and components using digital blueprints [1][2][3]. In contrast to traditional subtractive manufacturing methods, an arbitrary 3D object can be built layer-by-layer from the bottom up; thus, this technique is also referred to as additive manufacturing.…”