Stresses in the Blades of a Cargo Ship Propeller

Experimental unsteady and time average loads on the blades of the CP propeller on a model of the DD-963 class destroyer for simulated modes of operation / by Stuart D. Jessup, Robert J. Boswell, John J. Nelka.

“…The maximum values of measured total forces and bending moments increased over the corresponding values without hull pitch by 5 percent for quasi-steady simulation and by 23 The simulated acceleration condition did not expose the propeller to higher peak loads than those to which it is exposed during full power steady-ahead operation. However, these loads are very sensitive to the maneuver simulated and substantially higher peak loads could be developed during other acceleration maneuvers.…”

“…Figure 12 indicates that the variation of the signals with blade angular position are adequately represented by the number of harmonics retained. Figure 13 shows that there are no significant resonances for any of the loading components below the 23rd harmonic, which corresponds to (23)x(14.08)=324 hertz. This is higher than the lowest frequency resonance obtained in the results presented in Reference 2; i.e., 247 hertz.…”

The effects of hull pitching motions and waves on periodic propeller blade loads / by Stuart D. Jessup, Robert J. Boswell ; presented at the fourteenth Symposium on Naval Hydrodynamics, the University of Michigan, Ann Arbor Michigan, 23-27 August 1982.

“…Lipis (1975) and Tasaki (1975) review the mechanisms and procedures for predicting the effect of the seaway on periodic bearing forces which, in principle, also apply to unsteady loading on an individual blade. Keil et al (1972), Watanabe et al (1973), and Lipis (1975) present data from strain measurements on the blades of full-scale propellers in both calm and rough seas. Gray (1981) presents the modulation of blade rate hull vibration due to ship motion in a seaway.…”