| Pipeline system,as a medium transmission and transfer of heat equipment,has a wide range of applications in the mechanical industry.Due to its vibration problem,it brings many unnecessary losses and accidents.Therefore,it is a very urgent task to st-rengthen the research of pipeline vibration control.The traditional way of vibration re-duction is passive control,which has a less obvious effect and higher cost.Therefore,it is a novel way to use active or semi-active vibration absorption in the pipeline.The electromagnetic damping vibration absorber,as the representative of the active vibra-tion absorber,has the characteristics of sizeable dynamic force,noticeable effect,simp-le structure,and so on.Its research is more famous in recent years.Based on the semi-active vibration absorber,a new type of electromagnetic damping absorber is propo-sed in this paper.And the research is mainly focused on the vibration mechanism of the pipeline,the characteristics of the absorber parameters,the structural design,and the performance experiments.Specific research work is as follows:Firstly,the vibration of the pipeline is analyzed based on the vibration theory.Th-e finite element method is used to establish the mathematical model,then the two-degree-of-freedom vibration model of the pipeline and absorber system is established,and the dynamic analysis is carried out.According to the Euler-Bernoulli beam theory,t-he natural frequency of the experimental pipe is calculated to be 20.02 Hz.Based on the ANSYS Workbench,the modal analysis of the experimental pipeline is assessed,a-nd the first natural frequency is 19.202 Hz.The vibration mode of the pipeline combined with simulation was tested by the method of hammering and pulsating air-flow ex-citation.The natural frequency of the pipeline hammering in the vertical direction was 21.09 Hz,and the resonance frequency of the pulsating air-flow excitation was 21.48 Hz.It is found that the theoretical calculation value and simulation value of the natural frequency of the pipeline is basically consistent with the experimental value,which verifies the correctness of the above model.Secondly,the working principle of the new type electromagnetic damping vibration absorber is described by the law of electromagnetic induction.The analytical express-ion of magnetic induction intensity B is calculated based on molecular current and th-e magnetic charge model.The electromagnetic damping coefficient is derived from M-axwell’s equations and Ampere’s law.Based on the ANSYS Workbench,the simulatio-n of the distribution of magnetic field lines and magnetic induction intensity of permanent magnet models with different shapes was analyzed.Finally,according to the calculation and test data,the preliminary design of the main parts of the new electromagnetic damping vibration absorber is made,such as tu-ning mass housings,permanent magnets,springs,coils,etc.The model is processed,a-nd the performance of the vibration absorber is verified by experiments.The experimental results show that the vibration velocity of measuring point A is reduced from 4-5.65mm/s to 7.451mm/s,which is reduced by 38.20mm/s,and the vibration velocity af-ter vibration absorption is reduced by 16.3%,which is 83.7% lower than that before vibration absorption.And the effect is more pronounced.The data analysis shows that the new electromagnetic damping vibration absorber can effectively suppress pipeline v-ibration and realize multi-modal vibration absorption. |
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