For reasonable fatigue design and estimation of fatigue
durability considered fatigue strength and stiffness of the
automotive body structure, many fatigue data must be insured
according to the shapes, materials, and welding conditions of the
spot-welded lap joints. In general, the most typical and
traditional method for fatigue design of the spot-welded thin sheet
structure is curve of S-N curve. By the way, these curves are
varied according to the welding condition, material, joint
geometry, and fatigue loading condition. Thus, in order to
determine the fatigue design criterion for spot-welded joint having
specific dimension and geometry, additional fatigue tests according
to those factors are generally required. This indicates that a lot
of cost and time for it have to be consumed.
In this paper, an economical method improving such problems was
proposed. And, its reliability and performance were verified by the
theory of Weibull probability distribution. As a mechanical
parameter to determine the fatigue design criterion of spot-welded
structure, the maximum stress equation was defined by using
artificial neural network. By using the maximum stress equation and
the fatigue data previously obtained as the fatigue test results,
the fatigue design criterion of spot-welded joint could be
predicted without any additional fatigue tests. The results
predicted by this method showed good agreement with actual fatigue
test results.