He equated this to the radial elongation of the fastening between these two surfaces. Together with the equilibrium condition this gives a set of simultaneous equations, which equals the number of pairs of hooks. The equation also contains the term for misalignment of hooks, thermal gradients and centrifugal body forces in the fastening. He assumed equal distribution of load among tangs and used a concentrated load at the center of tang. Stress in the root attachment area is a function of geometry, material and tensile load.
Tensile load is a function of the speed of rotation.
Figure 1 shows an idealized structure with load on the root and a reaction force on the upper hook. It is difficult if not impossible to write a closed form solution to estimate stress in root attachment . The tensile load experienced by each hook depends on the resulting gap at other hooks of the blade root. Stress evaluation though important is secondary for this paper. Finite element technique has been employed to estimate stresses.