ETD

• Advanced Virgo
• analisys
• Ansys
• Cantilever Spring Blades
• CAOS
• design
• Einstein Telescope
• ET
• experimental
• FEM
• heat treatment
• INFN
• Matlab
• modal
• oxidation
• seismic filter
• seismic isolation
• stress relief
• structural
• super attenuator
• superattenuator
• titanium
• titanium alloy
• Virgo

The Einstein Telescope (ET) project represents the next generation of ground-based gravitational wave detectors, designed to achieve unprecedented sensitivity at low frequencies. To support this goal, the CAOS (Center for Applications on Gravitational Waves and Seismology) R&D platform at the University of Perugia serves as a full-scale testbed for developing and testing novel seismic isolation technologies. This thesis investigates the transition from Maraging C250 steel to Titanium Grade 5 (Ti-6Al-4V) for the cantilever spring blades of the Superattenuator. While Maraging steel provided the high strength required for the Virgo project, long-term service has highlighted reliability risks, such as high susceptibility to hydrogen embrittlement. Titanium Grade 5 is thus proposed as a pragmatic alternative to meet the stringent 30-year operational standard mandated for ET infrastructure. This thesis investigates the transition from Maraging C250 steel to Titanium Grade 5 (Ti-6Al-4V) for the cantilever spring blades of the Superattenuator.
The research integrates analytical modeling of triangular blades to derive material figures of merit and optimize filter geometry, specifically evaluating the trade-offs between the number of blades and the fundamental resonance frequency.
A key contribution is the definition of the complete manufacturing process, focusing on the development and validation of a single-step thermal cycle (550 °C for 2.25 hours). This workflow improves procedural efficiency and logistical feasibility by bypassing the complexities of standard Solution Treatment and Aging (STA).
Experimental results, supported by Finite Element Method (FEM) simulations, confirm that the established process meets the structural and stability requirements for CAOS filters. These preliminary studies lay the groundwork for future long-term characterization of the material for third-generation detectors.