中文摘要：

提出一种具有开槽结构的大尺寸立方形超声塑料焊接焊头的设计方法，并对其进行了实验验证．首先通过合理开槽将大尺寸立方形焊头划分为若干单元，然后将各焊头单元和立方形半波振子比较，利用等效机械阻抗的概念得出焊头单元的频率方程，其间考虑了耦合振动的影响．最后利用该方程研究了开槽数、槽宽度以及槽长度等因素对焊头振动特性的影响．按此方法设计加工了几组具有开槽结构的大尺寸立方形焊头，结果表明焊头谐振频率的实测值和理论值吻合得很好．

英文摘要：

A new design method for large cross-section ultrasonic plastic welding block horns with slots was presented and experimental validation on it was carried out. Firstly, the block horns are reasonably divided into some units, and then these units were compared with half wavelength block resonator with constant cross-section. By adopting the concept of equivalent mechanical impedance, the frequency equation of the mentioned horn element unit was obtained and meanwhile the influence of coupled vibration was taken into account. Finally, by utilizing this equation, the influence of the number of slots, their width and length on vibrating characteristics of horn were analyzed. In light of this design method, several groups of the target block horns are manufactured and the results indicate that the resonant frequency well agrees with the theoretic one.