COBEM99

S5 Controle Ativo de Vibrações e Estruturas Inteligentes

Title:

EXPERIMENTAL CHARACTERIZATION OF VISCOELASTIC MATERIALS

Summary :

ABSTRACT. THE PRESENT WORK AIMS TO DESCRIBE EXPERIMENTAL PROCEDURES FOR VISCOELASTIC MATERIALS, THROUGH THE DETERMINATION OF THEIR PROPERTIES - SHEAR MODULUS, G, AND LOSS FACTOR, H. THE USE OF VISCOELASTIC MATERIALS CAN INCREASE THE STRUCTURAL DAMPING, SO THAT VIBRATIONS LEVELS ARE REDUCED. THESE PROPERTIES AND SPECIAL FORMULATIONS HAVE PERMITED TO WRITE DOWN FREQUENCY AND DAMPING FOR STRUCTURES THAT ARE COMPOSED BY VISCOELASTIC MATERIAL LAYER BETWEEN TWO METALLIC LAYERS. IN THIS WORK TWO KNOWN METHODS WERE USED: THE STANDARDIZED AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM, 1993) KNOWN AS STANDARD TEST METHOD FOR MEASURING VIBRATION-DAMPING PROPERTIES OF MATERIALS AND THE INDIRECT METHOD (MASTERSON & MILES, 1995). A THIRD TECHNIQUE CALLED DIRECT METHOD, WAS ALSO DEVELOPED. TO VERIFY THE EFFICIECY OF THE METHODOLOGY USED IN THE ASTM METHOD, TESTS WERE ACCOMPLISHED TO CHARACTERIZE THE VISCOELASTIC SELF-ADHESIVE 3M-ISD. THE OBTAINED RESULTS WERE COMPARED WITH OTHERS TECHNICAL WORKS AND IT COULD BE VERIFIED THAT THE USED METHODOLOGY IS APPROPRIATE. TESTS WERE ALSO ACCOMPLISHED FOR OBTAINING THE PROPERTIES OF THE VISCOELASTIC SELF-ADHESIVE VERY HIGH BOND (3M-VHB), MANUFACTURED IN BRAZIL, AND THE THREE PRESENTED METHODS WERE USED. FROM THE COMPARISON OF THE OBTAINED RESULTS SOME CONCLUSIONS RELATIVE TO THE EMPLOYED METHODOLOGIES IN THESE METHODS ARE PRESENTED. KEYWORDS: VISCOELASTIC MATERIALS, STRUCTURAL DAMPING, VIBRATION DAMPING.

Author :

Faisca, Renata Gonçalves
Magluta, Carlos 0
Roitman, Ney 0

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