I. Equivalent stress (σ c) is calculated by the following formula or another formula specially approved by the Commandant (CG-522) as equivalent to the following:

where:

σx = total normal stress in “x” direction.

σy = total normal stress in “y” direction.

τxy = total shear stress in “xy” plane.

II. When the static and dynamic stresses are calculated separately, the total stresses in paragraph I are calculated from the following formulae or another formulae specially approved by the Commandant (CG-522) as equivalent to the following:

III. Each dynamic and static stress is determined from its acceleration component and its hull strain component from hull deflection and torsion.

[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]