The effects of tube orientation (horizontal/vertical), tube/support misalignment, fluid medium (air/water), tube/support-hole clearance, support thickness, exciting force amplitude, and support spacing on the vibrational characteristics (resonant frequencies, mode shapes, and damping) and displacement response amplitude of a multi-span tube were determined from thirteen different tests. The test model features a 15.875 mm (0.625 in.) dia x 3.175 mm (0.125 in.) thick x 5.232 m (206 in.) long seamless Croloy (2- exp 1 / sub 4 % Cr--1% Mo) tube, and combinations of four support thicknesses (12.70 mm ( exp 1 / sub 2 in.), 19.05 mm ( exp 3 / sub 4 in.), 38.10 mm (1 exp 1 / sub 2 in.), and 50.80 mm (2 in.)) and three sizes of diametral clearance of tube/support-hole (0.254 mm (10 mils), 0.508 mm (20 mils), and 0.762 mm (30 mils)). The test results were compared with the analytical results based on the multi-span beam with ''knife-edge'' supports. (ERA citation 02:029546)
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