Patent ID: 7752917
Filing Date: 2010-07-13
Classification: G01N,G06F

Abstract:
1. A fatigue life estimating method for a spot welded structure comprising the steps of: preparing a spot welded structure consisting of two or more plates joined together; providing a shell model from the spot welded structure for a finite element method analyzing process; subjecting the shell model to the finite element method analyzing process to calculate the peel load, the bending moment, the shear force, and the torsional moment as partial forces exerted on a nugget at the center of the spot welded structure as well as the deflection on the circumference of a circle which is D in the diameter and defined to have the nugget at the center; calculating the nominal structural stress responsive to the peel load, the bending moment, the shear force, and the torsional moment using a disk bending theory and a two-dimensional elastic theory of the elastodynamics with the calculations of the partial loads and the deflection, where components σ where a where r and θ are the polar coordinates, E is the Young's modulus, ν is the Poisson's ratio, t is the thickness, and A