• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.2
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• pp.49-58
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• 2003

The linear motor has not only no backlash and less friction, resulting in very high accuracy, but also mechanical simplicity, higher reliability, and longer lifetime. In this study, a large-capacity hybrid mass damper using linear motor principle has been developed to suppress vibration of large structures. It is designated linear motor damper in this paper. The LMD has been designed to be able to move the auxiliary damper mass of 155kg up to $\pm$250mm stroke. A series of performance tests for LMD control system with $H_{winfty}$ robust controller have been carried out on the full-scale steel frame structure. Through the performance tests, it is confirmed that vibration response levels are reduced down 10dB for the first and second modes of the test structure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.266-274
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• 2020

This paper reports a means of improving the abnormal noise of light tactical vehicles (LTVs) by applying a vehicle fitting type generator (hereinafter called generator). LTVs are classified as having generators, and there are no differences in the noise level. On the other hand, quality improvement was performed in response to unpleasant noise felt by the user (hereinafter called abnormal noise) during vehicle operation. To improve the quality, the generator mounting structure and the phenomenon of the vehicle in the problem were identified. Through this, it was confirmed that the noise caused by the generator installation was the rattle noise. Rattle noise at the engine driving system is normally caused by the transfer of irregular torque generated by the engine power stroke and the backlash by the spline-serration fitting structure between the engine coupler and rotor assembly in a generator. Therefore, this study established an improvement plan to apply a damper coupler to solve the cause of the abnormal noise. Regarding the improved establishment method, the improvement effect was confirmed from the influence of the irregular torque of the engine, noise level, dynamic characteristics analysis, and the endurance test of the parts.