Patent ID: 8689637
Filing Date: 2014-04-08
Classification: B23K,G01N

Abstract:
1. A fracture analysis method for a spot welded portion comprising: finding a maximum allowable load value of a welded portion in each of the predetermined fracture mode selected from the group consisting of a load fracture, a moment fracture, and a nugget interior fracture using a formula determined in advance based on at least a sheet thickness t, a tensile strength TS, an elongation El, and a chemical composition of a nugget portion in each of spot-welded steel sheets, a nugget diameter d of the welded portion, an effective width B of the welded portion determined by a distance between adjacent welded portions, edges or ridge lines, and a sectional height H; and finding an allowable load value in each of the predetermined fracture mode at every moment of a plurality of moments after the maximum allowable load value of the welded portion is reached by using spot welding modeled by a finite element method according to the predetermined fracture mode, and finding a displacement or a time at which the allowable load value becomes 0.