Measuring and calculating method for viscoelasticity dynamic mechanical parameters of damping material

Abstract

The invention discloses a measuring and calculating method for viscoelasticity dynamic mechanical parameters of a damping material. The measuring and calculating method includes respectively measuring reflection coefficients of a solid damping material covering layer and a damping material covering layer including a cylindrical cavity under the condition of normal incidence in a water-filled impedance tube; obtaining the longitudinal wave velocity of the damping material according to the reflection coefficient of the solid damping material covering layer; obtaining the shear wave velocity of the damping material according to the reflection coefficient of the damping material covering layer including the cylindrical cavity, in combination with eigen equation of wave propagation in a viscoelastic cylindrical tube; and obtaining viscoelasticity dynamic mechanical parameters such as elasticity modulus, shear modulus and Poisson's ratio according to constitutive relation. The covering layer sample for measuring viscoelasticity dynamic mechanical parameters of the damping material is simple in structure and easy to produce, and meanwhile the sample can accomplish acoustic characteristic measuring so that the cost is reduced; the limitation that the vibration beam method only has low frequency measuring results is overcome, effective measuring frequency bands of viscoelasticity dynamic mechanical parameters are effectively increased, and synchronization of parameter measurement and mechanism study is achieved.

Description

technical field [0001] The invention relates to a method for measuring and calculating viscoelastic dynamic mechanical parameters of a damping material, and belongs to the technical field of noise control. Background technique [0002] Sound waves are the only form of energy that can travel long distances in the ocean. At present and in the foreseeable future, underwater detection will still rely on the detection of changes in the sound field. Therefore, reducing its own radiation noise and acoustic reflection characteristics has become the main measure for underwater acoustic stealth of ships. [0003] Reducing self-radiated noise and acoustic reflection characteristics is a systematic project that requires overall acoustic design. The acoustic covering layer with viscoelastic damping medium as the base material is used as the outermost acoustic protection layer of the underwater moving body, which can not only detect the echo of the active sonar, but also have the functio...

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Problems solved by technology

However, these mechanical methods have their own limitations. For example, the forced non-resonance method (Zhao Jing, Hou Hong, Sun Liang, Longitudinal resonance method to measure the mechanical parameters of viscoelastic materials, noise and vibration control, No. The design requirements are relatively high, and the test frequency band of the vibrating beam method (Zong Fukai, You Yikuang, an improved vibrating beam method for measuring the properties of viscoelastic materials, Journal of Jiangsu Institute of Chemical Technology, No.3, 1991) is low, etc.

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