1. EXPERIMENTAL MESUREMENTS OF THE DYNAMIC PROPERTIES OF VISCOELASTIC MATERIALS AND SYSTEMS Imeko Technical Committee 15 2nd Youth Symposium on Experimental Solid Mechanics May, 7-10 2003 Milano Marittima (Ravenna), Italy Andrea Magalini, David Vetturi Dipartimento di Ingegneria Meccanica Università degli Studi di Brescia

2. 2nd Youth Symposium on Experimental Solid Mechanics 2 Rubber-to-metal devices Automotive applications: Vibrations-damping devices Vibrations- damping device for Mc-Pherson suspensions Engine mountings Adaptive journal boxes

3. 2nd Youth Symposium on Experimental Solid Mechanics 3 Materials Dynamic properties of elastomers Visco-elasticity Non - linearity Frequency dependence Temperature dependence Static pre-strain dependence HysteresisSelf-heating Stress Strain Temperature

4. 2nd Youth Symposium on Experimental Solid Mechanics 4 Experimental analysis Electro-dynamic shaker Fixtures Standard test-pieces Rubber-to-metal devices Material properties: Sweep of sine waves at constant deformation levels Shaker Vibrating board Test specimen Suspended mass Device global stiffness: K* E*G*

5. 2nd Youth Symposium on Experimental Solid Mechanics 5 Measurement chain Output AccelerationsSystem Frequency responseStiffness Shaker PC &Controller PowerAmplifier ADC Acceleration measurement Temperature measurement Drive signal Power drive Data Test Design DAC

6. 2nd Youth Symposium on Experimental Solid Mechanics 6 Stiffness measurement Suspended mass acceleration a OUT Imposed acceleration a IN Sine waves System global stiffness k System frequency response System global stiffness k( ) Youngs modulus E( )

7. 2nd Youth Symposium on Experimental Solid Mechanics 7 Deformation level increase causes: Results Effects of the deformation level decrease of E growth of E Pre-strain level increase causes: Effects of pre-strain, deformation and frequency G [MPa] growth of E

8. 2nd Youth Symposium on Experimental Solid Mechanics 8

9. 9

10. 10 Conclusions and discussions