非接触多磁环负刚度机构非线性刚度行为特性研究

Nonlinear stiffness behavior of non-contact multi-magnetic ring negative stiffness mechanism

工程车辆行驶和作业速度低、载荷大,驾驶员和乘员常全身暴露于低频大幅振动,导致作业效率低,甚至引发严重的振动职业病。准零刚度隔振系统具有高静-低动刚度特性,可有效过滤低频振动能量。接触式负刚度机构可带来摩擦损耗等问题,导致负刚度机构力学形态的不稳定。开发了基于非接触多磁环负刚度(non-contact negative stiffness,NCNS)机构和气动人工肌肉(pneumatic artificial muscle,PAM)正刚度机构并联的准零刚度隔振系统。为探明系统刚度行为机理,以多磁环负刚度机构为研究对象,基于比奥-萨伐尔定律和安培定律建立了负刚度解析模型;分析了不同参数(充磁强度、几何参数和磁场强度)下负刚度机构的刚度行为特性,并开展了验证实验。结果表明,轴向充磁比径向充磁可获得显著的负刚度特性;增加磁环外径、厚度及磁场强度均可提高负刚度机构的承载性能,但不改变其负刚度区间;增加上下磁环间距可扩展负刚度区间,但不改变其承载性能;计算模型与实验结果之间的校正决定系数为0.99975,计算模型满足精度要求。为下一步准零刚度隔振系统建模、参数优化及其工程应用提供了理论基础。

Due to low speed and heavy load of engineering vehicles,drivers and passengers are often exposed to vibrations with low frequency and large amplitude to cause low working efficiency and even serious vibration occupational diseases.The quasi-zero stiffness isolation system has characteristics of high static and low dynamic stiffness,it can effectively filter low-frequency vibration energy.A contact mechanism with negative stiffness can bring friction loss and other problems to cause the instability of mechanical morphology of negative stiffness mechanism.Now,a quasi-zero stiffness vibration isolation system is developed based on the parallel connection of non-contact negative stiffness(NCNS)mechanism and positive stiffness mechanism of pneumatic artificial muscle(PAM).Here,in order to find out the mechanism of stiffness behavior of the system,taking a multi-magnetic ring negative stiffness mechanism as the study object,the analytical model of its negative stiffness was established based on Biot-Savart’s law and Ampere’s law.The stiffness behavior characteristics of the mechanism under different parameters of magnetizing intensity,geometric parameters and magnetic field intensity were analyzed,and the verification tests were conducted.The results showed that axial magnetizing can obtain significant negative stiffness characteristics compared with radial magnetizing;increasing magnetic ring’s outer diameter,thickness and magnetic field intensity can improve the load-bearing capacity of the mechanism,but can’t change its negative stiffness range;increasing spacing between upper and lower magnetic rings can expand its negative stiffness range,but can’t change its load-bearing capacity;the correction determination coefficient between the calculation model and test results is 0.99975,the calculation model meets accuracy requirements;the study results can provide a theoretical basis for further modeling,optimizing parameters and engineering application of quasi-zero stiffness vibration isolation systems.