Variable stiffness concepts enable structural adaptation through smart materials with inherent stiffness variation or innovative configuration-based designs using conventional materials. This study focuses on SMP-based concepts for shape control and vibration mitigation. A dual-layer beam model relates stiffness variation to thickness and modulus ratios. Stiffness variations directly affect structural frequencies and are often accompanied by damping ratio variations, which is critical for semi-active vibration control. SMP-based components (e.g., joints, sandwich plates) enable vibration mitigation, although their efficiency depends on structural form. This study provides insights into frequency shifts, damping variations, material usage, and structural forms as key design parameters. A parametric study identifies principles for material distribution and vibration control efficiency, forming a design framework applicable to a wide range of systems.

Variable stiffness concepts enable structural adaptation through smart materials with inherent stiffness variation or innovative configuration-based designs using conventional materials. Among these, multilayer jamming (MLJ) provides rapid, reversible, and controllable stiffness modulation via vacuum-induced interlayer friction. This study proposes an MLJ-reinforced inflatable system for adaptive stiffening and enhanced energy dissipation in rapidly deployable lightweight structures. First, the influence of layer stiffness on MLJ performance is examined, identifying a suitable stiffness range for efficient reinforcement and providing guidance for material selection. A meter-scale prototype combining MLJ plates and an inflatable airbeam is then experimentally investigated under varying vacuum pressures, layer configurations, and loading conditions. The results show that vacuum activation significantly enhances stiffness and stabilizes the structure against collapse under reduced internal pressure. Quasi-static cyclic tests demonstrate that a 10 kPa vacuum condition achieves the best balance between stiffness enhancement, stable yielding, and energy dissipation, with dissipated energy increasing by 32–44% and ultimate load capacity by up to 38%. A simplified analytical model is developed to interpret stiffness evolution and the interaction between MLJ sliding and structural response. This work establishes MLJ as a scalable and designable material system for adaptive composite structures, with potential applications in construction, aerospace, and robotics.