An identification method for frequency dependent material properties of viscoelastic sandwich structures

Koffi Senanou Ledi (1) , Mohamed Hamdaoui (1) , Guillaume Robin (1) , El Mostafa Daya (1)

1 LEM3 - Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux

In this paper, an inverse identification method of the viscoelastic material properties (shear modulus G 0 and loss factor h C) of a symmetric three layered viscoelastic sandwich beam is proposed. Experimental vibration tests are performed to determine resonant frequencies and loss factors for different bending modes. The inverse approach consists into an iterative procedure that determines the mode shapes given the material parameters and then computes the viscoelastic properties from the modes using a Rayleigh quotient until convergence on the material properties is met. As a result, the frequency dependent viscoelastic material properties of sandwich beams are determined in an automated fashion. The method is successfully compared to the Ross-Kerwin-Ungar formulas and to a standard optimization approach. A fit of the viscoelastic material properties is performed providing analytical expressions for these quantities over a wide range of frequencies.

Mots clés: Inverse problem; Rayleigh quotient; Finite element model; Vibrations; Viscoelasticity; Sandwich structures

Domaines: Sciences de l'ingénieur [physics]; Mécanique [physics.med-ph]; Vibrations [physics.class-ph]; Mécanique des structures [physics.class-ph]

Koffi Senanou Ledi, Mohamed Hamdaoui, Guillaume Robin, El Mostafa Daya. An identification method for frequency dependent material properties of viscoelastic sandwich structures. Journal of Sound and Vibration, 2018, 428, pp.13-25. ⟨10.1016/j.jsv.2018.04.031⟩. ⟨hal-02085990⟩