Estimation of Air Borne and Solid Borne Sounds Radiated from Enclosures

1.用有限元法和边界元法计算了机器振动面被相邻板屏蔽时产生的声压分布。在上一个财政年度，处理了振动表面和隔音板之间的空间被刚性墙壁封闭的情况。在本财政年度，我们处理的个案是外围是开放式的，噪音可以透过外围及嵌板向外发出。该程序还可以估计附接到面板上面向振动表面的一侧的吸声材料的效果。通过计算结果与几种分析结果的比较，检验了程序估算的可靠性。将计算结果与实验结果进行了比较，两者吻合较好 ...更多信息 其他2.本文提出了一种分别估算含有噪声和振动源的封闭空间表面噪声的固体分量和空气分量的方法。首先研究了一种理论，根据在噪声和振动源连接到外壳的点处测量的加速度来估计固体承载部件的量。然后进行实验来检验理论是否正确。实验中使用的实验室由钢框架和钢板组成。该源可以产生具有可调节幅度的噪声和振动。用本方法估算了源运行过程中在封闭空间外测量的固体噪声分量。将估算结果与声源离开封闭空间时的实测噪声进行了比较，验证了方法的可靠性。此外，还推导出了一种估算源施加在壳体上的力的方法。少

1. Computer programs were written to estimate the sound pressure distribution produced when a vibrating surface of a machine was shielded by a panel located adjacent to it. The finite element method and the boundary element method were employed for the estimation. In the last fiscal year, the case was dealt with where the priphery of the space lying berween the vibrating surface and the sound shielding panel was closed by rigid walls. In this fiscal year, the case was dealt with where the periphery was open and the noise could be emitted outside through the periphery as well as through the panel. The programs could also estimate the effect of the sound absorbing materials attached to the panel on the side facing the vibrating surface. The reliability of the estimation made by the programs was examined by comparing the computed results with several analytical results. Computed results were also compared with the experimental ones, and it was found that both results agreed well with each … More other.2. A medhod was deviced to estimate separately the solid borne component and the air borne component of the noise emitted from the surfaces of an enclosure containing a noise and vibration source. First a theory was studied to estimate the amount of the solid borne component on the basis of the acceleration measured at the points where the noise and vibration source was attached to the enclosure. Then experiments were carried out to examine if the theory was proper or not. The enclosue used in the experiments was made up of a steel framework and steel panels. The source could produce noise and vibration with adjusted magnitudes. The solid borne component of the noise measured outside the enclosure during the source operation was estimated by the present method. The result of the estimation was compared with the noise measured when the source was supported free from the enclosure, and the reliability of the methob was examind. In addition a method was derived to estimete the force the source applied to the enclosure. Less