Development of the estimation method of energy flow path inside the 3-dimensional structure using surface velocity data and finite element method

结构强度测量有助于了解振动能量在物体内部的传递路径，迄今已有许多研究报道。然而，由于在厚结构中测量内部振动分布的困难，大多数工作只针对薄体，如梁或板。在本研究中，我们提出了一种新的适用于厚体的SI测量方法。在给定被研究物体的密度、声速、尺寸以及激励和吸收位置的前提下，利用局部表面振动数据，用有限元法进行动力分析，计算出结构内部的整体振动分布。利用这些结果可以估计整个SI分布。在此基础上，我们成功地对厚振动体进行了多次SI测量。该方法的优点是：(1)只需要结构的表面振动数据就可以估计整个SI分布。(2)如果先验地满足上述条件，则适用于任意三维结构。在研究中，还研究了测量误差和所需测量数据数的影响。

Many studies about structural intensity (SI) measurement, which is useful to know transmission paths of the vibration energy in a body, have been reported until now. Most of the works, however, have been done only for thin bodies, such as beams or plates because of the difficulty in measuring interior vibration distribution in thick structures. In this research, we propose a new SI measurement method applicable to thick bodies. The entire vibration distribution in the structure is calculated by dynamic analysis of finite element method (FEM) from the partial surface vibration data if the density, the sound velocity, sizes of a body under study and the locations of excitation and absorption are given apriori. The entire SI distribution can be estimated using the results. Based on this method, we have successfully carried several SI measurements for thick vibrating bodies. The merits of this method are as follows: (1) Only surface vibration data of the structure is needed to estimate the entire SI distribution. (2) It is applicable for arbitrary 3-D structures if the conditions mentioned above are satisfied apriori. In the research, the influence of the measurement error and the required number of the measurement data are also investigated.