Measurement of the Structural Intensity

本研究的目的是检验双加速度计方法测量结构强度的准确性，并探讨该方法在结构噪声和振动问题中的应用。利用一根部分覆盖有阻尼材料的钢梁对结构强度测量系统的精度进行了测试。具体地说，由激振器提供的振动功率是由阻抗头测量的。根据梁上测量的结构强度计算振动功率。通过计算功率与实测功率的比较，验证了结构强度测量系统的精度。(3)利用部分覆盖有阻尼材料的平板钢板对结构强度测量系统的精度进行了测试。具体地说，由激振器提供的振动功率是由阻抗头测量的。根据测得的结构强度，计算了激振点周围的闭合直线和与平板横向相交的直线通过的振动功率。通过计算功率与测量功率的比较，验证了测量系统的精度。(4)开发了基于有限元的计算程序，对含阻尼材料平板的结构强度进行了计算。通过比较计算值和实测值，可以看出板上结构强度的测量和计算都具有足够的精度。此外，还考察了阻尼材料对振动功率流模式的影响。(5)讨论了结构强度分布与板弯曲振动节线移动的关系。

The purpose of this study were to test the accuracy of structural intensity measured by the so-called two accelerometer method and to discuss the application of the method to the problems of noise and vibration of structure.Following results were obtained in this study:(1) The accuracy of vibrational power measured by an impedance head was tested by a mechanical method and an electrical one. It was observed that the vibrational power was accurately measured.(2) The accuracy of a structural intensity measuring system was tested using a steel beam partly covered by damping material. Specifically, the vibrational power supplied by the exciter was measured by an impedance head. The vibrational power was calculated based on the structural intensity measured on the beam. The accuracy of the measuring system was found to be sufficient by comparing the calculated power with the measured one.(3) The accuracy of the structural intensity measuring system was tested using a flat steel plate partly covered by damping material. Specifically, the vibrational power supplied by the exciter was measured by an impedance head. The vibrational power passing closed lines encircling the exciting point and straight lines intersecting the plate laterally was calculated based on the structural intensity measured on the lines. The accuracy of the measuring system was found to be sufficient by comparing the calculated power with the measured one.(4) An FEM based computer program was developed to calculate the structural intensity on the flat plate with damping material. The sufficient accuracy of both the measurement and calculation of structural intensity over the plate was observed by comparing the calculated distribution with the measured one. In addition the influence of damping materials on the mode of vibrational power flow was examined.(5) The relation between the structural intensity distribution and the movement of nodal lines of bending vibration of the plate was discussed.