Research on mode conversion of Lamb wave at end of elastic plate

The research on the condition that an incident sound wave excites the Lamb wave in underwater elastic plate and the mode conversion of the Lamb wave at the end of submerged elastic plate may become the basis for underwater target recognition. By the conversion solution for the mode equation of the elastic characteristic function,the energy reflecting coefficients of various modes of Lamb wave are solved when some mode of Lamb wave becomes incident into the end. The measurement experiment result on the scattering waves of the submerged elastic plate shows that,only when the incidence is applied at the critical angle of some mode of Lamb wave,this mode of Lamb wave may be directly excited in the elastic plate,while the other modes of Lamb waves are formed by reflection of this mode of Lamb wave at the end of the elastic plate. By the measurement and comparison for the sizes of leaky wave of various modes of Lamb wave in water,the theory on mode conversion and energy re-distribution at relevant ends are verified.