Lunar construction is challenged by harsh environments and limited resources. Inflatables, with their inherent adaptability, offer promising solutions. This study introduces rigidizable inflatable lunar habitats using silicone-coated aramid fabric (SC-AF) as restraint layer and shape memory polymer (SMP) for rigidization. SC-AF exhibits excellent mechanical stability, folding capability, and tear resistance. After one fold, stiffness dropped by 17 % with negligible strength loss. X-ray micro-computed tomography (μCT) analysis revealed fiber deformation, misalignment, and coating micro-cracks, while fiber integrity remained almost intact. After 500 folds, stress dropped 19 % and stabilized after 10,000 cycles. Even after 50,000 folds, the material retained 29 % of its original strength without major fiber rupture, confirming Kevlar’s toughness. Practical applications involve fewer folds and less repetitive angles, allowing for a 20 % design safety margin. A theoretical dual-layer beam model evaluates equivalent stiffness based on material stiffness and thickness ratios, offering design limits and guidelines for rigidization and vibration control. For the SMP used, a thickness ratio of 0.02 or 1 is recommended, not exceeding 5. Rigidization capability should align with structural load-bearing requirements. This study integrates analytical, experimental, and numerical methods to advance high-strength restraint materials, examines folding-induced performance changes, and establishes design principles for SMP-based variable stiffness applications.

Variable stiffness concepts enable structural adaptation to diverse environments, categorized as smart materials or specialized configuration designs. Multi-layered jamming (MLJ) provides a rapid, reversible, and easily controlled actuationmethod. This study examinesMLJ-based variable stiffness components for rapid construction and energy dissipation in civil engineering, focusing on an MLJreinforced Tensairity beam and construction procedure. The numerical model shows the structure's enhanced load-bearing capability post-vacuuming. During large deformation, energy dissipation via interlayer friction produces hysteresis loops, which may benefit to mitigate dynamic responses. While these techniques show promise, challenges exist concerning material limits, application boundaries, quantification, and precise shape control. They could also find utility in environments with confinement pressures like soil or water, expanding the potential applications.

Constructing lunar bases is crucial as lunar missions progress towards utilization and exploitation. The challenging lunar environment, with its unique characteristics and limited resources, requires special materials, structures, and construction methods. Inflatable structures offer great potential for lunar construction due to their advantages in transportation, stowage, construction, and reliability. This paper proposes a rigidizable inflatable lunar habitat that maintains its shape even after air leakage, enhancing safety, durability, and fixability. The membrane material adapts to different requirements during transportation, construction, and service, achieved through solid-state actuation of shape memory polymer (SMP) for stiffness variation, allowing multiple moves and ground tests. This work comprises three parts: 1) system: design concept and construction processes, 2) material: design and characterization of restraint and rigidization materials, and 3) structure: numerical validation of structure properties. Finite element analysis, based on material models obtained through dynamic mechanical analysis (DMA) and tensile tests, demonstrates the effectiveness of including an SMP rigidization layer in preventing collapse and enhancing dynamic properties. This paper not only proposes a new system, but also provides material design methods and requirements, along with structural validation techniques. Findings validate the feasibility of rigidizable inflatable lunar habitats, applicable in extreme environments, also in temporary buildings, space structures, and soft robotics.

The design of FRP profile-concrete composite sections, including beams and decks, is usually governed by the shear strength of the FRP profiles. However, analytical methods that can precisely predict the shear capacity of the composite sections have not been well developed, because there is lack of knowledge of the FRP-concrete composite action and distribution of shear stress along the FRP. This paper investigates the shear behaviors of FRP-concrete composite sections and develops formulae to predict the shear capacity of the composite sections. First, flexural tests of three FRP-concrete composite beams were conducted to investigate the shear failure mode and interface behaviors. All the beams failed in FRP shear fracture along horizontal direction. Then, push-out tests were used to determine the slip property for the FRP-concrete interface which reveals that FRP stay-in-place form and steel bolts can ensure full and partial composite action, respectively. Based on the experimental study, closed-form equations to compute the maximum shear stress are derived and validated against experimental data in this paper and literature. Finally, simple yet reliable equations of shear capacity are derived and recommended for engineers to design the FRP-concrete composite sections.