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smac-sas ZI Toulon-Est BP 119 83079 Toulon Cedex 9 France

Innovative Visco Elastic Dampers for Shock and Vibration Control Tony DEMERVILLE (SMAC, tony,demerville@smac.fr ). www.smac-sas.com ZI Toulon-Est BP 119 83079 Toulon Cedex 9 France. What about visco elastic materials ?

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smac-sas ZI Toulon-Est BP 119 83079 Toulon Cedex 9 France

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  1. Innovative Visco Elastic Dampers for Shock and Vibration Control Tony DEMERVILLE (SMAC, tony,demerville@smac.fr) www.smac-sas.comZI Toulon-Est BP 119 83079 Toulon Cedex 9 France

  2. What about viscoelasticmaterials? Polymermaterialswithvarious additives (Vulcanizing agents, reinforcing charges, protecting agents,…) Viscoelasticmaterial = Thermosetmaterial Various possibility to tune the material regarding the requirements, and the environnementconditions,as the space constraints Outgassing values of SMACTANE 50 SP

  3. Viscoelasticmaterials and mechanicalbehavior Soft materialwith an extremeflexibiliy : Hyper-elacticbehavior Visco-elasticitydefined by a storagemodulus (E’) and a lossmodulus (E’’) Ultimate tests on IMU damper

  4. Viscoelasticmaterials and mechanicalbehavior Effect of the temperature on the moduli : Effectof the frequencyon the moduli : SMACTANE 50 SP and DMA tests

  5. Viscoelasticmaterials and mechanicalbehavior Effectof the strainonthemoduli : Visco-elasticmaterial = Various No linearityeffects but veryinteresting to solvedynamicproblems ! PAYNE EFFECT SMACTANE 50 SP and DMA tests

  6. Viscoelastic damper for SEIS/INSIGHT payload INSIGHT : NASA Discovery Program mission on Mars proposed by JPL withseveraleuropeanpartners Objectives : To improve the scientific knowledge about the planet formation process by measuring the planet “vital signs” View of the SEIS Payload

  7. Viscoelastic damper for SEIS/INSIGHT payload Launch phase & Landing phase : Random + Shocks About the Shockevents : Usuallaunchshocks, Activation of lock actuators , deployment of seismometer,…. The payloadcan not survive to thismechanicalenvironment !!! SMAC isselected to design a visco-elastic damper to protect the SEIS payload

  8. Design of the dampers : Review of the specification Mass of the suspendedpayload : 8,0Kg Localisation of the dampers : Alignedwith the suspendedCoG Mechanicalrandomlevels : 7,16 grms Shockenvironment profile : 2200g from 2kHz up to 10kHz

  9. Design of the dampers : Review of the specification Temperature range, Random : -20°C / +45°C Temperature range, Shockevents : -50°C / +35°C (Mars landing) -60°C / +60°C (Release events) Random and Attenuationrequirements : ShockAttenuationrequirements :

  10. Design of the damper, choice of the visco-elasticmaterial Visco-elasticmaterial : Verylow Glass Temperature (Tg) to becompliantwith the requiredattenuation up to -60°C ! The SMAC rubberref MB1176-01 (FS-7286-02) wascompounded ) Spaceenvironmentconstraints (outgassing, radiation, ageing) : OK

  11. Design of the damper, stiffnessassessment and rubbershape Stiffnessassessmentcoupledwithallowable volume : A conicalrubbershapeischoosen : The Axial/Radial stiffness ratio isdriven by Dext, H, t and α Staticstiffness : Analyses by FEMs (HyperelasticNeo-Hooke behaviorlaw) Dext H t α

  12. Design of the damper, stiffnessassessment and rubbershape The nominal rubber design (Mock-up type A) isdefined by analyses : Short schedule and no-lineareffects of rubber : 2 back-up rubber design (Mock-up tye B and type C) are defined (and manufactured) !

  13. Design of the damper, QMs & FMs View of the QMs/FMs design: Externalmetallichousing : Titanium (Ta6V)

  14. Final configuration, QMs & FMs Evolution of the input data : Following X&Y axis (IP), the CoGis not centeredregarding the location of the 3 dampers ! There is a major risk not to get the attenuation rate due to the rocking modes ! Solution : To increase the stiffness of the damper located close to the CoG by adjusting the rubbercompund (MB1176-01=>MB1183-01) « Soft damper » « New » positioning of CoG « Soft damper » « Hard damper »

  15. Random qualification tests, QMs & FMs Random qualification tests : -20°C, +20°C & +45°C (ADETESTS Lab) Mechanicalstrenght : OK (lowevolution of the FFT under sine lowlevel) :

  16. Random qualification tests, QMs & FMs Attenuationunderrandomlevels : OK for the 3 axis from -20°C up to +45°C Y axis, -20°C Z axis, -20°C

  17. Shock tests: Suspended vs No-Suspendedpayload Shock tests based on a dummy mass and Frangibolt activation (CNES pyrolab) A soft damper isreplaced by a « rigiddamper » Soft Damper Rigid Damper

  18. Shock tests: Suspended vs No-Suspendedpayload Main results in rigid configuration :

  19. Shock tests: Suspended vs No-Suspendedpayload Main results in soft configuration :

  20. Pyroshocktestingunderextreme qualification temperatures At -52°C : Z axis (OOP)

  21. Pyroshocktestingunderextreme qualification temperatures At -52°C X axis (IP) Y axis (IP)

  22. CONCLUSIONS Visco-elasticmaterialcanbetunedregardingSpaceOperationalConditions (temperature, outgassing, radiations,…) Used as shock and vibration control thanks to damper, isolatorntuned mass damper, structural damping,…. New way : Earth observation satellite and decoupling of spinningactuaorswhichcaneffect the quality of pictures !

  23. Thank you for your attention SMAC Company

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