1. Magnetic Vibration Damper for Space Applications Planning Concept Developme nt DesignFabrication Test & Verification Mission: To develop a prototype of a solid state eddy current damper for use in satellite and aerospace applications and to deliver it with an accurate analytical model of system performance and test fixture in 25 weeks. Team (left to right): Jake Norris (ME)- Fabrication Engineer Tom Sciotto (IE)- Lead Engineer Tiffany Heyd (ME)- Simulation Engineer Ben Hensel (ME)- Test Engineer Dr. Alan Raisanen- Faculty Guide Special Thanks to: Phil Vallone of ITT Rob Kraynik and the entire ME shop staff Dr. Linda Barton Dr. Marca Lam Dr. Mark Kempski Dr. P. Venkataraman P11566 20101 / 20102 Customer NeedParameterSpecification Critical to deliver prototype that matches analytical model. 10-25% Damping Constant Zeta appropriate stiffness of system Damping Coefficient Zeta10% to 25% ½" range of motion mandatory, desired 1"Amplitude±0.25" to ±0.50" Component for space applications Operating Temperature-40° C to 80° C Operating Pressure Envelope0 Pa Has to last 10 yearsLifecycle158,000 cycles Weight must be less than 10kgMass<1 kg Payload to be damped is approx. 60 kg (system of 6 dampers)Load10 kg System must not be affected by magnetic field beyond 6" Magnetic Field Strength @ 6" from<20 mG @ 6" Need to damp 1 Hz vibration in motion and 100 Hz vibration while stationary Frequency (maneuver) 1 Hz Frequency (stationary)100 Hz No tin, zinc, or organic volatiles Not suitable for space applications due to "whisker" formation and off gassing. No Rubbing of Components Very difficult to model "stick slip" occurrences. Factor of safety of 2 Copper vane is free to move through magnet array. Flexure constrains motion Layers promote easy modification Cast iron bridges magnetic field, amplifies power greatly Known issues: During testing it was difficult to find a consistent method to vibrate the damper. While exploring different options and trying different techniques, a shift in the magnetic array caused rubbing. It is unknown whether the model matches the prototype, or what level the prototype was performing at before the array shift happened. Unit is very heavy, assumptions were made that the actual unit would contain aero grade materials. Unable to test at temperature extremes or in vacuum. Proposed Work: Use non-conductive magnetic bridge to make simpler magnetic field. Attempt to design to last for proposed life cycle. Make continuous strides to reduce weight of the unit. Consider designs that would reduce possibility of rubbing. Consider trade off of swapping copper for aluminum conductor (conductivity vs. weight). Effect on damping coefficient from increasing magnet layers. Test fixture with unit attached to shaker table …before the test caused the shaker to overheat. Damping Force (lbf) Damping Coefficient, c (lbf-s/in) Spring Constant, k (lbf/in) Zeta (%) Experimental0.651.3182.877.25% Theoretical1.813.6220.8713.83% Difference64% 297%48% Theoretical eddy current produced from conductor moving through a pair of magnets at 0.5 in./sec (from COMSOL).