固体表面法向力条源的辐射阻抗及各种波型的能量分布
The radiation impedance and the energy partition among wave fields generated by a normal force strip radiator on isotropic solid surface
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摘要: 本文主要研究了固体表面法向力条源在各向同性固体中的辐射阻抗和辐射能量。在研究辐射能量时,用辐射导方法求出辐射源的辐射总能量,用远场的声场求出法向力源所辐射的各种波型(表面波、切变波和压缩波)的能量,结果表明:(1)条源的宽度变宽时,压缩波所占的能量比例增加;(2)当条宽在某一个小的范围内取值时,几种波型所占的能量比例几乎相等;(3)对于不同的条源宽度,用辐射导方法求出的总能量等于用声场方法求出的三种波型的能量之和。这不但证明了固体表面法向力条源激发弹性波时能量的守恒,而且也进一步映证了用稳相法得到的远场声场的正确性。Abstract: The radiation impedance and energy partition among elastic waves generated by a normal force strip radiator on isotropic solid surface are investigated in this paper.Two methods are used to obtain the radiation energy.One is to get the total radiation energy from the radiation conductance.And the other is to get energy of each elastic wave at far field.The results indicate:(1) the energy ratio of the longitudinal wave increases with the width of the radiator becoming wider;(2) the energy of each elastic wave is naerly same while the width of the radiator changes in a small range;(3) for different width of the radiator,the total energy gotten from the radiation conductance is equal to the energy sum of each wave gotten at far field.This not only proves the conservation of the energy for generated elastic waves,but also mutually reflects that approximate expressions of wave fields obtained from the method of the steepest descents are correct.