In this paper, the pressure wave form of the impact sound is discussed theoretically and experimentally, which is radiated from the end surfaces of a ram in the deformation process of a billet. The impact sound may be attributed to air pulses caused by the sudden acceleration of the ram. The impact sound wave at a field point is calculated by superimposing those emitted from the divided small elementary areas of the end sur-faces. In the calculation, it is assumed that the approximate acceleration of the ram changes sinusoidally, and that the shelter effect due to the ram can be ignored when the wave length of impact sound is larger than the dimensions of the ram. The superimposed sound pressure wave forms agree fairly well with those measured by laboratory experi-ment, and show fairly well the change of wave forms due to different measuring points.
衝撃による円柱ラムの放射音特性
kiyo35_rikou_pp63-70.pdf
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