| The frame is one of the most important components on a portable air compressor. It is not only the installed base which can bear the weight of the other components, but also will be motivated by the Engine and the rough road in transit.Once the natural frequency is close to vibration frequency, the frame will be resonance and produce larger dynamic load, its working stability will be affected. Also, it can be damaged and even ruptured. So it is very important to ensure that the rigidity and intensity of the frame is appropriate, and also it should have good vibration characteristic. With the help of CAE analysis software,we had comprehensive studied the vibration characteristics of the frame in the mobile compressor by combining the finite element method with experiment test analysis method.Firstly, the geometric model of the structure of the frame was established by 3D mapping software UG which has the powerful modeling function. Secondly, simplified the geometric model of the frame in the Hypermesh software, then adopted shell element to mesh it, and simulated the connection part by using the appropriate way. Finally, the finite element model of the frame was established. Then the finite element software is used to calculate constraint modal of the frame structure, the natural frequency and vibration mode of frame was obtained. Described the characteristics of vibration modes, and evaluated the results of modal calculation. Then we have a preliminary understanding of the vibration characteristics of the frame structure. In addition this paper, two kinds of working condition of frame for harmonic response analysis and random vibration response analysis were carried out on the engine harmonic excitation and road roughness excitation.Displacement- frequency response curve of all nodes was obtained by harmonic response analysis which is based on the harmonic excitation of the engine. And the results of the calculation were analyzed, determined frequency points which the frame occur resonance,vibration test was carried out on the frame by using LMS Test. Lab Test system, then the results of the harmonic response analysis were verified. The acceleration-amplitude response curve of the frame was obtained by random vibration response analysis which is based on pavement power spectrum. Determined frequency points which the frame occur resonance, demonstrated the accuracy of analysis results by road test.The analysis results showed that the analysis method which was combined the finite element method with experimental test is useful for us to have a comprehensive understanding of frame vibration characteristics. It can ensure the accuracy of the vibration characteristics analysis results and provide a theoretical basis for the improvement of the frame structure. And this method can be used as an enterprise one of the means of the follow-up frame structure design and improvement. |
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