双质体振动磨动力学建模及参数优化

摘要

针对多自由度振动磨系统建模困难以及动力学参数优化设计的需要，根据拉格朗日方程建立双质体振动磨6自由度动力学方程，利用数值分析方法分析了系统的动力学响应，并通过振动测试试验验证了模型的有效性。在振动微分方程的基础上研究了激振器转速对振动磨动力学特性的影响，仿真结果表明在一定范围内，转速越大，振动强度越大，但振动幅值越小。为了使振动磨产生更好的粉磨效果，对激振参数进行优化分析。利用模态分析获得双质体振动磨的固有频率和振型，分别从振动强度和共振频率两个角度确定系统激振器转速的上下限，得到转速的最佳取值范围。在实验室振动磨样机上进行参数优化后的粉磨试验，实验结果表明，改进后的振动磨机金刚石粉体产品 d50达到0．27μm，较之前有所细化，验证了参数优化具有一定的工程效果，为振动磨超微粉碎的动力学设计和产品开发奠定了基础。%Aiming at the needs of modelling and dynamic parametric optimization design of vibration grinding systems with multi-DOF,the dynamic equations with 6-DOF of a double-mass vibration mill based on Lagrange equation were established.The dynamic response of the double mass vibration mill was analyzed using the numerical analysis method and the model was verrified to be effective with vibration tests.The relationship between the double mass vibration mill's dynamic characters and the rotating speed of its exciter was studied with the help of the established model.It was shown that the larger the rotating speed,the bigger the vibration intensity,but the smaller the vibration amplitude.In order to achieve the better effect of grinding,the excitation parameters were optimized.With the help of modal analysis, the natural frequencies and vibration modal shapes of the system were obtained.The upper limit of the rotating speed was determined with the resonance frequencies and the lower limit was determined with the vibration intensity.Then,the optimal range of the rotating speed was determined.A grinding test with diamond powder was conducted on the model machine.The result showed that the average size of output powder is 0.27 μm,it meets the requirements of ultrafine powder.This optimization laid a foundation for dynamic design and product development of vibration mills for ultrafine comminution.