18 research outputs found
The effects of sheet spacing on the fatigue life of spotwelded joints
While investigating the fatigue strength of spot-welded joints, the effects of
sheet spacing or gap amounts between sheet joints may be considered as one of
the most important parameters on the fatigue life duration of the joints. The
main goal of the present work is to study the influence of sheet spacing on the
fatigue life of 5083-O aluminium alloy spot welded tensile-shear joints. The
amounts of sheet spacing are the average values over three measurements of
photograph observation of the cut-off surfaces from the nugget centre of the
spot-welded joints. The amounts of gap distances between spot weld sheet joints
for three different electrode clamping force levels were 0.09mm, 0.11mm and
0.13mm, respectively. The values of notch strength reduction factors have been
obtained at all levels of applied loads based on volumetric approach. The
fatigue lives of spot welded joints have been obtained according to the
volumetric method using the notch strength reduction factors and the available
smooth S-N curve of 5083-O aluminium alloy sheets. The results based on the
volumetric approach have been compared with the experimental fatigue test data
and there is good agreement between numerical predictions and experimental
results
Fatigue life estimation for different notched specimens based on the volumetric approach
In this paper, the effects of notch radius for different notched specimens has been studied on the values of stress concentration factor, notch strength reduction factor, and fatigue life duration of the specimens. The material which has been selected for this investigation is Al 2024T3 . Volumetric approach has been applied to obtain the values of notch strength reduction factor and results have been compared with those obtained from the Neuber and Peterson methods. Load controlled fatigue tests of mentioned specimens have been conducted on the 250kN servo-hydraulic Zwick/Amsler fatigue testing machine with the frequency of 10Hz. The fatigue lives of the specimens have also been predicted based on the available smooth S-N curve of Al2024-T3 and also the amounts of notch strength reduction factor which have been obtained from volumetric, Neuber and Peterson methods. The values of stress and strain around the notch roots are required to predict the fatigue life of notched specimens, so Ansys finite element code has been used and non-linear analyses have been performed to obtain the stress and strain distributions around the notches. The plastic deformations of the material have been simulated using multi-linear kinematic hardening and cyclic stress-strain relation. The work here shows that the volumetric approach does a very good job for predicting the fatigue life of the notched specimens