ABSTRACT
Tensegrity structures provide both structural integrity and flexibility through the combination of stiff struts and a network of flexible tendons. These structures exhibit useful properties: high stiffness-to-mass ratio, controllability, reliability, structural flexibility, and large deployment. The integration of smart materials into tensegrity structures would provide additional functionality and may improve existing properties. However, manufacturing approaches that generate multimaterial parts with intricate three-dimensional (3D) shapes suitable for such tensegrities are rare. Furthermore, the structural complexity of tensegrity systems fabricated through conventional means is generally limited because these systems often require manual assembly. Here, we report a simple approach to fabricate tensegrity structures made of smart materials using 3D printing combined with sacrificial molding. Tensegrity structures consisting of monolithic tendon networks based on smart materials supported by struts could be realized without an additional post-assembly process using our approach. By printing tensegrity with coordinated soft and stiff elements, we could use design parameters (such as geometry, topology, density, coordination number, and complexity) to program system-level mechanics in a soft structure. Last, we demonstrated a tensegrity robot capable of walking in any direction and several tensegrity actuators by leveraging smart tendons with magnetic functionality and the programmed mechanics of tensegrity structures. The physical realization of complex tensegrity metamaterials with programmable mechanical components can pave the way toward more algorithmic designs of 3D soft machines.
ABSTRACT
Calcium carbonate (CaCO3) and monodisperse calcium oxide nanoparticles (CaO NPs) are prepared by the calcination of solid-state calcium oleate precursor in air condition. The effect of calcination temperature on the synthesis of CaCO3 and CaO NPs is examined. The polymorphism is confirmed by X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The sample morphologies including their size and size distribution are investigated by field emission scanning electron microscopy (FESEM). Calcination of calcium oleate between 400 and 550 °C results in CaCO3 NPs with mean sizes from 82 to 98 nm, whereas monodisperse spherical CaO NPs are obtained at 650 °C and an average size is estimated to be 40 nm. Beyond 650 °C, the size of CaO NPs increases with broad size distribution. The results of this study provide a novel approach to monodisperse CaCO3 and CaO NPs that can be applied in a variety of fundamental and industrial fields.
