抄録
The dispersion curve of a curved beam has negative slope at a frequency region. A wave packet which is synthesized by more than two waves at the region of negative slope has negative group velocity. This paper addresses an issue of engineering application of the negative group velocity. Firstly, a dimensionless frequency of dispersion curve was introduced to achieve negative group velocity, in order to establish a design method of vibration reduction in mechanical structures. Then, backward movement of wave energy with negative group velocity was realized by using the design method, and was verified using transient response analysis of a FE-model of a curved beam. Validation was carried out from the standpoint of both negative group velocity of a wave packet and backward movement of vibration intensity. The results show that the wave energy in a curved beam does not propagate in the positive direction along the axial direction of a waveguide.
