In this study, a lightweight sandwich aircraft spoiler (AS) with a high stiffness-to-weight ratio was designed. Excellent mechanical properties were achieved by the synthetic use of topology optimization (TO), lattice structure techniques, and high-performance materials, i.e., titanium alloy and aluminum alloy. TO was first utilized to optimize the traditional aircraft spoiler to search for the stiffest structure with a limited material volume, where titanium alloy and aluminum alloy were used for key joints and other parts of the AS, respectively. We then empirically replaced the fine features inside the optimized AS with 3D kagome lattices to support the shell, resulting in a lightweight sandwich AS. Numerical simulations were conducted to show that the designed sandwich AS exhibited good mechanical properties, e.g., high bending rigidity, with a reduction in weight by approximately 80% when compared with that of the initial design model. Finally, we fabricated the designed model with photosensitive resin using a 3D printing technique.

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Quasi-zero-stiffness (QZS) vibration isolators have been widely studied, because they show excellent high static and low dynamic stiffnesses and can effectively solve low-frequency and ultralow-frequency vibration. However, traditional QZS (T-QZS) vibration isolators usually adopt linear damping, owing to which achieving good isolation performance at both low and high frequencies is difficult. T-QZS isolators exhibit hardening stiffness characteristics, and their vibration isolation performance is even worse than that of linear vibration isolators under a large excitation amplitude. Therefore, this study proposes a QZS isolator with a shear-thinning viscous damper (SVD) to improve the vibration isolation performance of the T-QZS isolators. The force-velocity relation of the SVD is obtained, and a dynamic model is established for the isolator. The dynamic responses of the system are solved using the harmonic balance method (HBM) and the Runge-Kutta method. The vibration isolation performance of the system is evaluated using force transmissibility, and the isolator parameters are analyzed. The results show that compared with the T-QZS isolators, the proposed QZS-SVD isolator achieves the lower initial vibration isolation frequency and peak value, and exhibits better vibration isolation performance at medium and high frequencies. Moreover, the proposed isolator can withstand a large excitation amplitude in the effective vibration isolation range.

Although the flexible origami gripper can handle a wide range of objects, there is a need for significant further improvement in its gripping performance. This study develops a novel nonlinear topology optimization (NTO) method to enhance the gripping performance of an origami chomper-based flexible gripper. The proposed NTO method incorporates the additive hyperelasticity technique and multi-resolution design (MRD) strategy with the advantages of being computationally efficient, having excellent convergence, and enabling refined design. The effectiveness of the proposed NTO method is validated by two compliant mechanism benchmark examples, i.e., the displacement inverter and gripper mechanisms. We apply the NTO method to the origami chomper-based flexible gripper to redistribute the material at the creases to obtain the optimized origami chomper-based flexible gripper. Several optimized origami chomper-based flexible gripper prototypes are fabricated by using laser cutter, followed by a series of experiments to test the gripping performances, including gripping range capability under an identical input load, maximum gripping ratio, gripping adaptability, and achieving richer gripping characteristics by size scaling. Results demonstrate that the optimized origami chomper-based flexible gripper can handle a wide range of objects irregularities in textures and uneven shapes;and the gripping range capability can be significantly enhanced by the NTO method. We also show that the optimized origami chomper-based flexible gripper can enable effective gripping of objects across scales from millimeters to centimeters to decimeters through size scaling.