The ultrasonic bone scalpel was often used in all kinds of clinical orthopedic surgery as a new type of medical instrument. Based on the working theory of the ultrasonic bone scalpel and combined with the design method of a quarter wavelength transducer and horn, this study proposed an optimization design method for the ultrasonic bone scalpel with a composite horn structure. The structure of the ultrasonic bone scalpel was simplified, and its length was shortened. Finite element analysis, modal analysis, and harmonic response analysis were used to optimize the design of the ultrasonic bone scalpel. The performance of the ultrasonic bone scalpel was explored through impedance analysis, amplitude measurement, temperature measurement, and cutting tests, and the feasibility of the design was verified through torque analysis. The results showed that when the torque force was 4.0 N, the resonance frequency of the ultrasonic bone scalpel was 30,540 Hz, and the maximum amplitude of the ultrasonic bone scalpel could reach 62 μm. After spray cooling, the maximum surface temperature of the rear end cover was reduced from 51.8 to 36.3 ℃, the maximum surface temperature of the composite horn was reduced from 71 to 45.3 ℃, and the maximum surface temperature of the cutter head was reduced from 101 to 46.1 ℃, demonstrating a good cooling effect. Under 89 Voltage, the optimal cutting force for cutting chicken leg bones was 0.1 N, the optimal cutting force for cutting pork ribs was 0.3 N, and the cutting process showed tissue selectivity.

超声骨刀作为一种新型医疗器械，常用于临床各类骨科手术。基于超声骨刀的工作原理，结合四分之一波长换能器和变幅杆的设计方法，提出了一种复合变幅杆结构超声骨刀的优化设计方法。简化了超声骨刀的结构，缩短了长度。采用有限元分析、模态分析和谐波响应分析对超声骨刀进行优化设计。通过阻抗分析、振幅测量、温度测量和切割试验探索超声骨刀的性能，并通过扭矩分析验证设计的可行性。结果表明，当扭力为4.0 N时，超声骨刀的共振频率为30540 Hz，超声骨刀的最大振幅可达62 μm。喷淋冷却后，后端盖最高表面温度由51.8℃降低至36.3℃，复合喇叭最高表面温度由71℃降低至45.3℃，刀头最高表面温度由101℃降低温度达到46.1℃，具有良好的冷却效果。 89电压下，切割鸡腿骨的最佳切割力为0.1 N，切割猪排骨的最佳切割力为0.3 N，切割过程表现出组织选择性。