黏接结构中超声波的能量反射与透射特性

针对黏接结构中超声波的能量反射与透射机理问题,研究了板状黏接结构界面为理想连接时,纵波以不同角度入射下的声波与界面的相互作用.分析了入射角度、频厚积对声波能量反射与透射特性的影响.结果表明:当纵波垂直入射时,不发生波型转换;随着频厚积的增大,纵波的能量反射与透射系数曲线出现明显的周期性谐振.当纵波倾斜入射时,波型转换会发生;随着频厚积的增大,纵波与横波的能量反射与透射系数无周期性谐振现象.当入射角小于90°时,纵波的位移势反射系数始终大于能量反射系数,而横波的位移势反射系数与能量反射系数曲线随着角度的增大会出现交叉.

Reflection and Transmission Characteristics of Ultrasonic Energy in the Adhesive Structure

To study the mechanism of energy reflection and transmission of ultrasonic in the adhesive structure, under the assumption of perfect connection, the ultrasonic wave interaction with the interfaces of plate-like adhesive structure was studied when the longitudinal waves were incident with different angles. The effects of the incident angles, frequency-thickness product on the reflection and transmission characteristics of ultrasonic energy were analyzed. The numerical results show that when the longitudinal waves are vertically incident, the conversions of wave mode do not occur, with the increment of frequency-thickness product, the reflection and transmission coefficient curves of energy of longitudinal waves obviously produce periodical resonance. When the longitudinal waves are obliquely incident, the conversions of wave mode will happen, as the product of frequency-thickness increases, the reflection and transmission coefficients of energy of longitudinal and transverse waves do not have periodical resonance. For the case of the incident angles less than 90°, the displacement potential reflection coefficients of longitudinal waves are always bigger than the energy reflection coefficients;however, the reflection coefficient curves of displacement potential and energy for transverse waves occur cross with increasing angles. The results provide a theoretical basis for the experimental detection of adhesive structure by ultrasound.