### ASA 125th Meeting Ottawa 1993 May

## 4aSA2. A modal power balance approximation for point connected flexural
beams.

**Peter Kasper
**

**
Paul Bremner
**

**
Paris Constantine
**

**
**
*Vibro-Acoustic Sci. Ltd., Level 5, 15 Orion Rd., Lane Cove, NSW 2066,
Australia
*

*
*
In recent years, the application of power flow techniques to the analysis
of beams and plates has led to an increased understanding of how noise is
transmitted through structures. When applied in terms of mode-to-mode
transmission, power flow evaluation has promise in modeling dynamic response at
frequencies for which statistical energy analysis is not appropriate. Modal
power flow calculations can, however, be computationally prohibitive. This
paper introduces a modal power balance approach by which the computational
effort can be reduced. The approach involves formulating the mode-to-mode power
exchanged between two beams in terms of a set of modal power balance equations.
These equations are analogous to the sub-system power balance equations of
statistical energy analysis. By introducing suitable approximations, the
equations can be integrated over frequency and length to express power flow
relationships in terms of band-limited, modal mean-square values. The approach
is applied to the configuration of two force and moment coupled flexural beams.
The results are compared with a classical modal solution.