A fuel-filled propel1ant tank was subjected to a single shaker random excitation in the frequency range of 10 to 380 Hz. Due to the schedule and practical limitations the only information available on the input excitation was the shaker acceleration. Because of this limitation, transfer functions had to be developed from acceleration ratio. Due to the coupling effects of the liquid and the test fixture to the shake table, the input frequency spectrum was not flat over the frequency range of the test. This created a number of large non-modal peaks which needed more careful curve fitting strategy to identify the real modes.
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