“The Effect of the Tubes on Stresses and Deflections in U-Tube Steam Generator Tube Sheets” W. J. O’Donnell, Bettis Technical Review, No. 21, p. 89, November 1960.
Keywords: steam generator; tube sheets; ligament strains
The results of tests run on an actual steam generator tube sheet are used to evaluate the effect of rolled-in tubes on stresses and deflections in the perforated portion of the tube sheet. Measured ligament strains are compared with theoretical values calculated for two cases: (1) assuming that the rolled-in tubes contribute no support to the tube sheet, and (2) assuming that the entire thickness of the rolled-in tubes is effective in stiffening the tube sheet and reducing ligament strains. Strain values calculated for Case No. 1 are found to average more than 75% higher than measured strains, and strain values are calculated for Case No. 2 are found to agree with average measured values within about 5%. It is concluded that the tubes contribute substantial support to tube sheets, and this support should be included in design calculations by taking the ID of the as-rolled tubes as the diameter of the perforations.