Fatigue mechanisms and residual stresses of stainless steel clinched joints
(English)Manuscript (preprint) (Other academic)
The fatigue crack initiation of clinched joints has been investigated. In rectangular clinches, fatigue cracks grow from the cuts made during clinching. Those cuts, in this case perpendicular to the load, act as cracks and stress raisers and are already present before fatigue loading begins. Residual stresses measured in the area where the cracks grow are tensile and could therefore be detrimental to the fatigue life, but since the magnitude of the stress is low the influence on the fatigue life should be small. In round clinches, fatigue cracks initiate outside the clinch on the die side surface of the punch side sheet. Fractography with SEM shows that the fatigue cracks are initiated in a region with fretting damage on the surface of the punch side sheet. Residual stresses measured in the region where fatigue cracks initiate are compressive but the influence on the fatigue life is probably small since the value of the stress is low.
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-102008OAI: oai:DiVA.org:liu-102008DiVA: diva2:667345