PSI - Issue 32

D.A. Oshmarin et al. / Procedia Structural Integrity 32 (2021) 158–165 Oshmarin D.A., Iurlova N.A., Sevodina N.V., Iurlov M.A. / Structural Integrity Procedia 00 (2021) 000 – 000

164

7

+ + + +

+ +

- -

0 (s/c)

75.906 0.828 1.177

∞ (o/c) 77.249 0.839 1.192

-

+ +

200 180

76.200 0.679 0.965

+

2.154

76.553 1.517

The obtained results show that in case when piezoelectric element is located for the best damping of the specified vibration mode a change in value of resistance of the resistive circuit leads to a considerable increase in damping of vibration at this mode. For the other vibration mode, the increase in damping properties is also observed but its magnitude is much less than for the target mode. Thevaluesofresistanceprovidingmaximalvalue of damping coefficient are different for different modes. A joint application of two approaches to damping of vibrations (supplement of a structure with a viscoelastic layer and a piezoelectric element shunted with a resistive R-circuit) allows obtaining higher values of coefficients of vibration damping than in case of application of each of mechanisms separately. Theresultsofinvestigationscarried out for both options of mutual arrangement of viscoelastic element and piezoelectric element shunted with the R circuit (location of piezoelectric element and value of resistance is chosen to provide maximal damping for the vibration mode under consideration) are represented in table 1. Intable 1 there also represented results for two modes of operation of piezoelectric element: open circuit mode and short circuit mode. The analysis of the results leads us to a conclusion that both design options results in comparable level of vibration damping. Herewiththemostpreferableoptionistheonewhenpiezoelectricelementandviscoelasticlayerareatoppositesides of the plate. Thisconfigurationallowsreachingminimalinfluenceonvaluesofnaturalvibrationfrequenciesofanoriginalstructure. Itisalsoimportanttopointoutthataddingapiezoelectricelementshuntedwiththesimplestresistivecircuittoastructurecompl etelycoveredwith a viscoelastic layer provides more than two times increase in damping coefficients. Thisresultis achieved in case when optimal configuration (optimal location of piezoelectric element and optimal value of resistance) is realized. 4. Conclusions Thus, the carried-out research demonstrated that forming an electro-viscoelastic system by combining a viscoelastic layer and a piezoelectric element shunted with an R-circuit allows considerably increasing dissipative properties of an original structure in case of selecting an optimal configuration. It was shown that ajointapplicationoftwodampingmechanisms under consideration provides better results than application of each of mechanisms separately. We established that  layout of a piezoelectric element and a viscoelastic layer at opposite sides of the plate leads to higher values of coefficient of vibration damping;  mutual arrangement of a piezoelectric element and a viscoelastic layer in relation to each other considerably affects the values of parameters of an electric circuit. It was demonstrated that in case of layout of a piezoelectric element over a viscoelastic layer (option 2) magnitude of parameters of the electric circuit is significantly decreased comparing to the case of damping without a viscoelastic layer. But in case of layout of a viscoelastic layer and a piezoelectric element at opposite sides of the plate the required value of parameters of the circuit is increased. Acknowledgements The research is supported by RFBR project № 19-01- 00158_а.