The following calculations for an independent tank type B must be specially approved by the Commandant (CG-ENG):
(a) Plastic deformation, fatigue life, buckling, and crack propagation resulting from static and dynamic loads on the tank and its support.
(b) A three-dimensional analysis of the stress exerted by the hull on the tank, its support, and its keys.
(c) The response of the tank and its support to the vessel's motion and acceleration in irregular waves or calculations from a similar vessel.
(d) A tank buckling analysis considering the maximum construction tolerance.
(e) A finite element analysis using the loads determined under Sec. 154.406.
(f) A fracture mechanics analysis using the loads determined under Sec. 154.406.
(g) The cumulative effects of the fatigue load from the following formula: [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] where: ni = the number of stress cycles at each stress level during
the life of the vessel;Ni = the number of cycles to failure for corresponding stress
levels from the Wohler (S-N) curve;Nj = the number of cycles to failure from the fatigue load by
loading and unloading the tank; andCw = 0.5 or less. A Cw of greater than 0.5 but not
exceeding 1.0 may be specially approved by the Commandant (G-
MTH). [CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]