Accession Number : ADA140221

Title :   Fatigue Considerations in View of Measured Load Spectra.

Descriptive Note : Final technical rept.,


Personal Author(s) : Dobson,W G ; Brodrick,R F ; Wheaton,J W ; Giannotti,J ; Stambaugh,K A

PDF Url : ADA140221

Report Date : Jan 1983

Pagination or Media Count : 59

Abstract : Crack propagation in HY-80 and CS ship steel under typical ship loading time-histories was studied. The loading histories were selected from recorded service stress data which were generated during voyages by the SL-7 containership. Samples of the data were imposed on laboratory specimens as a tape loop signal speeded up by a factor of 25. Analysis of the results indicated that the crack growth during this random loading compared closely with that of constant-amplitude loading if the stress intensity range were expressed as the root-mean-square. It was also determined that significant crack growth retardation effects were present and that omission of low-amplitude high-frequency components of the loading had little effect on the time rate of growth of cracks. The potentially large effects of environment on crack growth rate were recognized but were not included in the scope of this work. (Author)

Descriptors :   *Fatigue(Mechanics), *Steel, *Ship hulls, *Hulls(Structures), *Loads(Forces), Spectrum analysis, Measurement, Cracks, Crack propagation, Fracture(Mechanics), Retardation, Stress concentration, Residual stress, Bending, Test methods, Nondestructive testing, Random vibration, Environmental impact, Stress waves, Factor analysis, Front ends and surfaces, Equations, Geometry, Mechanical properties, Graphs

Subject Categories : Metallurgy and Metallography
      Marine Engineering
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE