Accession Number : AD0635181

Title :   FATIGUE TESTS OF SHIP WELDS.

Descriptive Note : Final rept. 31 Aug 45-31 Aug 47.

Corporate Author : CORNELL UNIV ITHACA N Y

Personal Author(s) : Hollister, S. C. ; Garcia,J. ; Cuykendall,T. R.

Report Date : 04 FEB 1948

Pagination or Media Count : 108

Abstract : The report summarizes the results of an investigation of the relative fatigue behavior of plates with (a) longitudinal ship welds, (b) reinforced and unreinforced flame cut openings, and (c) flame cut edges. The specimens, of the order of 12 to 17 inches wide 1nd 7 feet long, were constructed from 3/4in plate of semi-killed shipbuilding steel and were subjected to zero-to-tension loading in especially built fatigue testing machines. The stress range generally was 0 - 30,000 psi tension. Fatigue control specimens were flat plates of tensile-coupon shape with flame cut edges. It was concluded that for a stress range of approximately zero-to-30,000 psi tension the characteristics of the flame cut edge were not significant in determining fatifue life within 500,000 cycles of stress. In comparison to the control specimens, longitudinal welds showed a greatly reduced fatigue life. All fatigue fractures started in the weld metal itself, usually in regions of porosity, deep surface ripples, poor root fusion, etc. Improved fatigue life for specimens with ground weld surfaces indicates that surface ripples, folds, or pits are incipient points of fatigue failure. The change in width from 12in to 16in is not believed to be a significant. All specimens with reinforced openings had a very short fatigue life (less than 30,000 cycles). Unreinforced, as cut, openings had a greater fatigue life than the reinforced openings. Treatment of the surface by grinding or by heat treatment markedly increased the fatigue life. (Author)

Descriptors :   (*WELDS, FATIGUE(MECHANICS)), (*FATIGUE(MECHANICS), *SHIP PLATES), STEEL, STRESSES, FRACTURE(MECHANICS)

Subject Categories : Metallurgy and Metallography
      Couplers, Fasteners, and Joints
      Marine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE