VARIABLE STRESS CYCLE FATIGUE OF LARGE BUTT-WELDED SPECIMENS

AN EXPERIMENTAL INVESTIGATION WAS CONDUCTED TO SHOW ON LARGER-THAN-LABORATORY SIZE SPECIMENS WHETHER OR NOT IT IS POSSIBLE TO INFLUENCE THE ENDURANCE LIMIT OF A WELDED STRUCTURAL JOINT BY IMPOSING VARIOUS STRESS CYCLES PRIOR TO OR DURING ZERO-TENSION FATIGUE TESTING. THESE INCLUDED PRESTRESSING AND COAXING AS WELL AS IMPOSING TO SPECIMENS A GIVEN VARIABLE STRESS CYCLIC FATIGUE PROGRAM. SUCH VARIABLES ARE THOUGHT BY SOME TO REDUCE STRESS CONCENTRATIONS AND RESIDUAL STRESSES DUE TO WELDING WHILE OTHERS BELIEVE THEM TO BE DETRIMENTAL. FATIGUE TESTS ON THREE TYPES OF A373 STEEL SPECIMENS WERE CONDUCTED TO ESTABLISH S-N CURVES UNDER ZERO-TENSION CYCLIC STRESS AMPLITUDES BASED ON RESULTS OF RUPTURES IN 100,000 AND TWO MILLION CYCLES. THE THREE TYPES OF SAMPLES TESTED WERE' PLAIN PLATES, TRASVERSELY-WELDED PLATES WITH THE WELD REINFORCEMENT GROUND OFF, AND AS-WELDED PLATES. PRESTRESSING TESTS WERE PERFORMED ON AS-WELDED SPECIMENS AND ON WELDED SPECIMENS WITH REINFORCEMENTS REMOVED. IT WAS FOUND THAT PRESTRESSING GENERALLY IMPROVED THE FATIGUE LIFE OF THE SPECIMEN. THE STEPWISE INCREASE OF STRESSES, OR COAXING FROM BELOW ENDURANCE LIMIT, WAS CARRIED OUT TO INCLUDE A STUDY OF THE FATIGUE STRESS HISTORY AND CUMULATIVE DAMAGE. SOME PATTERNS OF STRESS HISTORIES RESULTED IN NOTED IMPROVEMENTS IN FATIGUE LIFE.

  • Supplemental Notes:
    • Vol 46, No 1, PP 39-5 - 48-5, 20 FIG, 5 TAB, 11 REF
  • Authors:
    • Welter, G
    • Choquet, J A
  • Publication Date: 1967-1

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  • Accession Number: 00208336
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 15 1994 12:00AM