Demonstration model, designed and built at NIKHEF
description
Transcript of Demonstration model, designed and built at NIKHEF
![Page 1: Demonstration model, designed and built at NIKHEF](https://reader037.fdocuments.in/reader037/viewer/2022103102/56816689550346895dda47df/html5/thumbnails/1.jpg)
Demonstration model, designed and built at NIKHEF
Geometric Anti Spring (GAS) FilterUsed for vertical seismic isolation
Horizontal compression of blades
Fx
Finite element analysisprestressed blade
Undeformed maraging steel blade
• A large mass (payload 4,8kg) is suspended from 3 blade springs. Initial resonance frequency f0 ≈ 5 Hz.• The blades are mounted on the filter plate. • The filter plate is set into oscillation with frequency f ≈ 10 Hz, using coil springs. This mimics seismic motion. • As f is larger than f0, the mass oscillates with smaller amplitude than the plate.
• By horizontal compression of the blades the stiffness strongly decreases, resulting into smaller f0 (≈ 0. 3 Hz) and a much larger attenuation.• The motion of plate and mass are measured with LVDT displacement sensors.
Mathematical analysis
200 mm
suspension wire
filter plate
keystone
Top view