本申请项目提出距振动前端面一定位置处开一横向方向的矩形通孔，优化设计孔位置及几何参数以达到增大变幅杆的振幅放大系数和纵振换能器的振幅并展宽频带的目的。结合有限元方法和遗传优化算法，分别以纵振换能器前端面的振幅、频带宽度，以及等截面变幅杆和系列变截面变幅杆的振幅放大系数为目标函数，以工作频率、大小端面的半径（若对换能器则为其前盖板的大端面的半径）为状态变量，以孔距离前端面的位置、孔的长度和宽度为设计变量，进行多变量优化设计，优化开孔位置及开孔尺寸，使目标函数达到最大。同理，优化设计大端面变幅杆输出端上的孔以增大振幅放大系数。计算矩形通孔对前辐射端面整体振幅分布、应力分布及位移节点的影响。设计并加工实心、开横向通孔及优化后的换能器及系列变幅杆，测试换能器的电压发射响应和-3dB频带宽度，测试换能器和变幅杆的振型、放大系数，验证理论计算结果，为功率超声和水声技术提性能更佳的换能器和变幅杆。

Enlargement of amplitude amplification factor for ultrasonic horns and amplitudes and frequency bandwidth for longitudinal transducers by means of optimization design of the geometrical sizes and the position of a transverse rectangle hole at front end. Combining the finite element method with the genetic optimization algorithm, taking the amplitude of the front end and frequency bandwidth of longitudinal vibration transducer respectively,, and amplitude magnification coefficients of uniform horn and of variable cross-section horns as the target functions, and taking operating frequency and the radius of the large and small end faces (for transducers being the radius of the large end face) as the state variables, and taking the distance of the hole from the front end surface and the length and width of the hole as the design variables, make the objective function achieve maximum by the method of multi-variable optimization design, and then, the optimized position and the geometrical sizes of the hole will be got. In the same way, the large amplitude amplification factor of ultrasonic horns with larger face output end will be studied by optimization design of the geometrical sizes and the position of a transverse rectangle hole at its front end. Furthermore, the influence of the hole on the whole amplitude distributions at the front end and on stress distributions of the transducer and the horn along their axial direction will be investigated by using the finite element method. All of above calculated and optimized results will be validated by experimental tests, including test of the amplitude magnification coefficients and vibration mode shapes of the ultrasonic solid uniform horns with no or with a hole, of variable cross-section ultrasonic horns with no or with a hole, and test of whole amplitude distributions at the front end, of voltage transmitting response, and of -3dB frequency bandwidth of a longitudinal transducer with no or with a hole. It will provide better performances and more applicable transducers and ultrasonic horns for power ultrasound and underwater acoustic technology through investigation of this kind of vibration system.