超声波振动农业触土部件变幅杆性能分析与试验

Performance Analysis and Experimental Study on Horn of Ultrasonic Vibration Agricultural Soil-engagement Component

针对超声波振动农业触土部件的结构要求,对比研究了指数型、悬链线型、圆锥型和阶梯型4种不同类型超声波变幅杆的谐振效应和聚能放大性能。利用变截面变幅杆的纵振波动方程求解得到4种变幅杆超声波激振下的轴向位移函数和应变分布函数,借助MatLab编程计算求得变幅杆轴向位移和应变分布和变幅杆的关键参数。结果表明:4种变幅杆的最大位移都发生在变幅杆的小端处,轴向应变曲线的最低点显示了易发生破坏失效变幅杆的极大应变点;相同条件下,4种变幅杆放大系数从大到小排列依次为阶梯型、悬链线型、指数型和圆锥型。阶梯型变幅杆虽然放大系数较大,但形状因数最小,过渡处易遭到破坏;圆锥型变幅杆的形状因数最大,其它两种居中。最后,分别通过有限元仿真分析和土槽试验的方法对计算结果进行验证,仿真与试验结果和理论计算结果保持较好的一致性。

According to the structural requirements of ultrasonic vibrating agricultural soil-engagement components,the resonance effects and amplification performance of four types of horns of exponential type,suspension chain type,conical type and stepped type are studied in comparison.The axial displacement function and strain distribution function of the four types of horns under ultrasonic excitation are obtained by solving the longitudinal vibration fluctuation equation of the variable section horn.The key parameters,axial displacement and strain distribution of the horns are calculated by using MATLAB programming.The calculation results show that the maximum displacement of the four types of horns occurs at the small end of the horns,and the lowest point of the axial strain curve shows the extreme strain point of the ultrasonic vibration horn,which is prone to damage failure.Under the same conditions,the amplification factors of the horn is ladder,catenary,exponential and conical from large to small.Although the amplification factor of the stepped horn is larger,its shape factor is the smallest and easy to be damage.The shape factor of the conical horn is the largest,and the other two types are in the middle.The calculation results are verified by finite element simulation and test,respectively,and the simulation and test results are in good agreement with the theoretical calculation results.