A passive and adaptive control method for stabilizing a pipe conveying fluid is presented. Owing to fluid–pipe interactions, pipes are subjected to excessive vibrations. Classical passive control methods are only valid for stabilizing the pipes over a narrow range of flow velocities. In this paper, the theory of nonlinear targeted energy transfer (TET) is applied to suppress the excessive vibration of a pipe by using an essentially nonlinear attachment, which is called a nonlinear energy sink (NES). Numerical evidence for a passive TET between the pipe and NES is proposed. Results show that the NES can robustly absorb and dissipate a major portion of the vibrational energy of the pipe.

Thermal metamaterials have been proposed to manipulate heat flux as a new way to cloak or camouflage objects in the infrared world. To date, however, thermal metamaterials only operate in the steady-state and exhibit detectable, transient heat signatures. In this letter, the theoretical basis for a thermal camouflaging technique with controlled transient diffusion is presented. This technique renders an object invisible in real time. More importantly, the thermal camouflaging device instantaneously generates a pre-designed heat signature and behaves as a perfect thermal illusion device. A metamaterial coating with homogeneous and isotropic thermal conductivity, density, and volumetric heat capacity was fabricated and very good camouflaging performance was achieved.