### ASA 127th Meeting M.I.T. 1994 June 6-10

## 3aSAa6. Optimization of structural vibration using energy concepts.

**Richard G. DeJong
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*Eng. Dept., Calvin College, 3201 Burton St. S.E., Grand Rapids, MI 49546
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Energy concepts are used to develop techniques for optimizing the design
and control of structural vibrations. In searching for a design that minimizes
the vibrational amplitude of a structure at a number of points and frequencies,
the minimization function is very irregular, having many local minima in the
design parameter space. This makes it difficult for automated search algorithms
to find a global minimum. The use of frequency-averaged energy levels as the
response variable provides a smoother minimization function and better results
from optimization algorithms. Similarly, in active control systems, the use of
measured point vibration amplitudes as the minimization function suffers when
the measured points correspond to the nodes in a modal response. The use of
structural intensity measurements as the minimization function helps to
overcome this problem. Several examples are given for beam and plate
structures.