Black hole damping control with a thermally-driven shape memory polymer
Résumé
Acoustic black holes are an emerging passive solution to control the propagation of waves without added mass. They consist in locally decrease the thickness of a main structure with an adequate power-law profile to slow down flexural waves. The higher the thickness contrast is, the higher the effciency is. The control of damping in the low stiffness area is important to ensure the vibration waves trapping: the stiffness decreases goes with a gradual damping increase. A strategy is developed in the presented work to actively control this damping by local heating of a memory shape-polymer like the tBA-PEGDMA whose elastic modulus and loss factor strongly depend on temperature. Studies are carried out to optimize the position of the viscoelastic material inside a given black hole, and the temperature distribution to decrease the reflection coeffcient . Is is shown that an optimize thermal field distribution in the adaptive polymer improves the properties of the black hole.