DESIGN OF METHOD FOR NONLINEAR SHEAR MODULUS MEASURING IN GEL-LIKE MEDIUM BY APPLYING AN ADDITIONAL STATIC STRESS TO AN ACOUSTIC RESONATOR

  • 1University of Zilina, Faculty of Mechanical Engineering, Department of Applied Mechanics, Zilina, SK
  • 2M.V. Lomonosov Moscow State University, Faculty of Physics, Department of Acoustics, Moscow, RU
  • 3University of Zilina, Faculty of Mechanical Engineering, Department of Automation and Production Systems, Zilina, SK
  • 4Sevastopol State University, Institute of Nuclear Energy and Industry, Sevastopol, RU

Abstract

Measurements of the nonlinear parameter of a gel-like medium were carried out in an acoustical resonator fixed without slipping between two solid-state boundaries. A sample of thickness L is fixed on an oscillating plate (x = 0). The other plate of finite mass on the free surface of the sample (x = L) moves together with this surface. By changing the mass of the plate (x = L), it is possible to achieve additional static deformation of the resonator up to 65%. The dynamic method assumes measuring resonance curves at various static deformations. Nonlinear properties appear at deformations of more than 20%. The nonlinear parameter and shear modulus measured dynamically were compared to static measurements where the dependence becomes nonlinear at strains greater than 30%. The static values of the shear modulus and the nonlinear parameter correspond to the values obtained in the dynamic method within an error.

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