Adjustable Ultra-Light Mechanical Negative Poisson's Ratio Metamaterials with Multi-Level Dynamic Crushing Effects.

Mechanical metamaterials with multi-level dynamic crushing effects (MM-MLs) are designed in this study through coordinate transformation and mirror arrays. The mechanical effects of the diameter and length ratio of the struts and connecting rods, the Euler angles, and the cell numbers on the mechanical properties are investigated separately. MM-ML can exhibit significant two-level platform stress, and the local cells in the first platform stress stage undergo rotational motion, while the second platform stress stage mainly involves collapse compression and bending.

Numerical Analysis of Space Deployable Structure Based on Shape Memory Polymers.

Shape memory polymers (SMPs) have been applied in aerospace engineering as deployable space structures. In this work, the coupled finite element method (FEM) was established based on the generalized Maxwell model and the time-temperature equivalence principle (TTEP). The thermodynamic behavior and shape memory effects of a single-arm deployment structure (F-DS) and four-arm deployment structure (F-DS) based on SMPs were analyzed using the coupled FEM.

Magnetic double-network composite capable of large recoverable deformation.

This paper presents the design and fabrication of a magnetic double network (DN) composite, which consists of permanent magnet chains embedded in an elastomer matrix, and was capable of large yet fully recoverable deformation. The initially connected magnets served as reusable sacrificial components in the composite. The strong magnetic attraction between neighboring magnetics endowed the composite with the high strength while the compliance of the elastomer matrix provided the high extensibility.

A highly stretchable double-network composite.

Inspired by the toughening mechanism of double-network (DN) hydrogels, a soft composite consisting of a fabric mesh and VHB tape layers was fabricated. The composite was as stiff as the fabric mesh, and as stretchable as the VHB tape. At certain compositions, the composite was significantly stronger and tougher than the base materials.