基于几何非线性的果蔬运输隔振系统设计

Design of Vibration Isolation System for Fruit and Vegetable Transportation Based on Geometric Nonlinearity

目的针对运输过程中振动与冲击造成果蔬损伤和品质下降的问题,基于非线性振动理论,提出一种几何非线性结构的果蔬运输隔振系统。方法首先,基于水平斜弹簧负刚度机构与垂向正刚度弹簧并联的方式设计果蔬运输隔振结构;其次,分析其静力学特性,推导该非线性隔振装置的刚度特性;最后,建立果蔬运输车模型的运动微分方程,采用谐波平衡法研究该新型果蔬运输车的隔振特性。结果研究结果表明,通过合理的结构参数设计,该隔振装置在平衡点附近具有高静态刚度、低动态刚度特性。对于小幅路面激励,该新型果蔬运输车将在全频段大幅优于对应的线性系统,随着路面激励幅值的增大,隔振装置刚度快速增加,频率跳跃线性逐渐出现,峰值逐渐出现并右移,中频段的隔振效果逐渐变差。高频段的隔振效果远优于对应的线性系统,且与路面激励幅值不敏感。结论通过引入水平预压缩弹簧与垂向弹簧并联形式的几何非线性结构显著提高了果蔬运输隔振系统的隔振效果,减小运输过程中果蔬所受到的振动与冲击,从而避免了果蔬损伤和品质下降。

The work aims to propose a vibration isolation system for fruit and vegetable transportation based on geometric nonlinearity according to the theory of nonlinear vibration.Firstly,the vibration isolation structure for fruit and vegetable transportation was designed based on the parallel connection of the horizontal oblique negative stiffness spring and the vertical positive stiffness spring.Secondly,the static characteristics of the structure were analyzed and the stiffness characteristics were derived.Finally,the motion differential equation of the fruit and vegetable transportation vehicle was established,and the harmonic balance method was adopted.The results showed that through the reasonable design of structural parameters,the isolator could achieve high static stiffness and low dynamic stiffness near the equilibrium point.For small road excitation,the proposed system would perform much better than the corresponding linear system.With the increase of road excitation amplitude,the stiffness increased rapidly,the jump phenomenon appeared,the peak value gradually appeared and shifted to the right and the vibration isolation effect in medium frequency band got worse.The performance in high frequency was always far superior to the corresponding linear system,and it had little relationship with the road excitation amplitude.By introducing the geometric nonlinear structure of parallel connection of horizontal pre-compression spring and vertical spring,the vibration isolation effect of fruit and vegetable transportation vibration isolation system can be significantly improved,and the vibration and shock of fruits and vegetables during transportation can be reduced,so as to avoid damage and quality deterioration of fruits and vegetables.