METAL MEMBER AND METAL STRUCTURE EXCELLENT IN FATIGUE CRACK DEVELOPMENT AND PROPAGATION SUPPRESSING CHARACTERISTICS, AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a metal member and a metal structure excellent in fatigue crack development and propagation suppressing characteristics which are used for buildings, ships, bridges, construction machinery, offshore structures or the like, and its manufacturing method.;SOLUTION: The metal member or the metal structure is formed in such a shape that a plate-like metal rib with a length of l, a height of h, and a thickness of t₂ is projected from a metal main plate or a metal main tube with a thickness of t₁. The metal member or the metal structure is characterized by comprising a dent 6 with a compressive strain of ≥0.5 and ≤25% in a plate thickness direction at a position 5 apart a distance (a) of ≥t₂/4 and ≤4×t₂ from a rib plate end part 4 where the main plate or the main tube crosses the rib in a direction parallel to an outside maximum tensile stress, the length b of the dent is such that the length (b) thereof from that position is ≥t₂/4 and ≤4×t₂ in the direction parallel to the outside maximum tensile stress, and the length L thereof in a direction vertical to the outside maximum tensile stress with respect to that position is ≥t₂/2 and ≤(5/8)W, and a compressive residual stress acts on the rib plate end part where the main plate or the main tube crosses the rib plate by the dent 6.;COPYRIGHT: (C)2007,JPO&INPIT