Low-frequency approximation and the choice of optimal elastic parameters for two-layer blast protection jackets" . Tikhonravov A.V., Trubetskov M.K., Winfree N.A., Kang J.H. Low-frequency approximation of elastic wave transmittance for two-layer structures is proposed. An accuracy of the approximation in a range up to several kilohertz is studied. Based on this approximation, the problem of the optimal elastic parameter choice for two-layer blast protection jackets is considered. ...