“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.

Our company President, Bill, Sr. began his career at Westinghouse/ Bettis in the Naval Nuclear Program under Admiral Rickover. He has served as the Chairman of the ASME Subgroup on Fatigue Strength for forty years, and has published numerous papers on design, fatigue and fracture.

O’Donnell Consulting performs engineering design and analysis to ASME Code including B&PV Section VIII Division 1 and 2 – as well as the Power & Process Piping Codes.

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