METHOD OF DETERMINING ELASTIC AND DISSIPATIVE CHARACTERISTICS OF COMPOSITE MATERIAL Russian patent published in 2019 - IPC G01N3/34 

FIELD: measurement.

SUBSTANCE: present invention relates to measurement, in terms of determining physical properties of materials, and can be used primarily for determination of elastic and dissipative constants of polymer composite materials (PCM) by non-destructive method in any industries. Method comprises processing of experimental values of natural frequencies and coefficients of mechanical losses corresponding to these frequencies of lower tones of bending and torsional oscillations of unsupported beams cut from plate of orthotropic polymer composite material at angle of 0, 45, 90°. Method enables to determine dissipative characteristics of polymer composite materials, wherein based on successive approximation procedure, according to which initial values of dynamic elastic moduli in direction of base and weft of reinforcing material, a shear modulus in the reinforcement plane and interlayer shear moduli in the warp and weft direction, determined by natural frequencies of the first tone of bending and torsional vibrations, as well as their corresponding loss coefficients, are refined using relationships based on the theory of Tymoshenko beam oscillations, using values of natural frequencies and corresponding loss coefficients of bending oscillations of unsupported beams of polymer composite materials of higher tones.

EFFECT: technical result is possibility of determining complex elasticity moduli E₁₁, E₂₂ and shift G₁₁, G₁₃, G₂₃, required for complete description of dynamic behaviour of thin-walled structures, including stiffness and dissipation characteristics of orthotropic PCM, having high accuracy and reliability.

1 cl, 2 dwg