METAL MEMBER OR METAL STRUCTURE EXCELLENT IN FATIGUE CRACK DEVELOPMENT AND PROPAGATION SUPPRESSING CHARACTERISTICS, AND METHOD OF MANUFACTURING THEM

摘要

PROBLEM TO BE SOLVED: To provide a metal member or a metal structure excellent in development and propagation suppressing characteristics for fatigue cracks generated from a stress concentration part at the end part of a rib, and a method for producing them.;SOLUTION: The metal member or the metal structure is formed in such a shape that a plate-like metal rib 2 with a thickness t of ≥1 mm, a height h of ≥3t and a length l is projected from a metal main plate or a metal main tube 1 with a thickness b. A compression pre-strain part 3 is formed in a thickness direction of the rib at the end part in the length direction of the rib. The compression pre-strain part 3 has a compressive strain of 0.5 to 25% in a plate thickness direction, the area p occupied on the rib surface is ≥0.67 t², the dimensions k in the length direction of the rib are 0.5t to 3(t×b)^0.5. the dimensions d in the height direction of the rib are 0.5t to 0.5h, the distance a between the centroid position thereof and the main plate or main tube 1 is ≤0.5h and also ≤3t, the distance e from the end part thereof to the end part in the length direction of the rib is narrower than the thickness t of the rib, and a compressive residual stress acts on the part 4 where the main plate or tube crosses the rib.;COPYRIGHT: (C)2007,JPO&INPIT