PSI - Issue 79

Girolamo Costanza et al. / Procedia Structural Integrity 79 (2026) 9–16

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Fig. 1. Ni-Ti material components: (a) commercial sheet material and (b) fabricated helical spring from Ni-Ti wire

SMA material memorizes the imposed configuration in the austenitic phase: L-shaped geometry for sheet components and helical coil geometry for spring elements, while maintaining optimal superelastic response characteristics. Figure 2 illustrates the shape setting process and resulting L-shaped geometry after heat treatment.

Fig. 2. Shape setting: (a) electric furnace setup and (b) L-shaped Ni-Ti sheet after heat treatment and water quenching

2.3. Device Fabrication and Assembly

The complete device fabrication process required systematic integration of multiple components to achieve a func tional seismic damping prototype. Wooden support structures formed the foundation of the assembly system, provid ing stable mounting points and ensuring consistent boundary conditions across all testing configurations. The support elements were precision-machined from hardwood to achieve the required dimensional accuracy and structural stabil ity. Upper and lower support blocks were designed with integrated mounting features to accommodate the L-shaped SMA elements and enable secure attachment to the testing apparatus. The wooden components incorporated precision drilled holes and threaded inserts to ensure reliable mechanical connections throughout the experimental program. Stainless steel threaded rods provided the primary load transfer mechanism between upper and lower supports, en abling direct force transmission through the device assembly. The complete assembly process integrated all components through a systematic procedure designed to ensure proper alignment and consistent boundary conditions. L-shaped sheets were positioned between upper and lower sup port blocks using precision alignment fixtures. Mechanical fasteners secured the SMA elements while maintaining the ability to apply controlled displacements during testing. For combined configurations, helical springs were installed in