Study of Design Parameters influence on the Fatigue Life of Riveted Joints
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Typ
Examensarbete för masterexamen
Master Thesis
Master Thesis
Program
Applied mechanics (MPAME), MSc
Publicerad
2019
Författare
Lövgren, Ingrid
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The aim of this study is to identify and investigate design parameters influence on the fatigue life of riveted joints. This to allow Volvo Group to fully utilize what the riveted joint has to offer. In the literature review many design parameters were identified as influencing the fatigue life of riveted joints. Some design parameters were chosen to be further investigated: hole geometry, hole treatment, plate material and rivet head design. Numerical and experimental investigations were conducted on a single riveted lap joint consisting of 15 mm solid rivets and 5 mm thick plates. A simulation of the riveting process was performed together with a simplified shear loading simulation of a lap joint. The numerical simulations were found to correspond well to experimental data such as deformation in shaped rivet head, stress fields, crack initiation and fretting location. Very few samples were investigated experimentally, limiting the statistically robustness of the results, but trends could still be observed. During the literature review three features were identified as necessary to consider to obtain a strong and robust riveted joint: the filling of the hole, the residual stress fields and the load transfer path. Furthermore, the most influential design parameter was identified as the riveting force. During numerical and experimental studies it was observed that the hole geometry influences residual stress fields and crack initiation. It was also indicated that the most detrimental hole geometry is the straight hole geometry, as residual hoop tension was observed after the riveting. Incomplete filling of the holes resulted in small voids, maximum of 1.0 x 0.5 mm, between rivet and plate interface. No detrimental effect of these voids was observed. In this study, large beneficial effects of hole treatments could not be confirmed at the investigated medium high load level. The shear loading simulation shows that the highest stress range occurs at the plate interface which corresponded to the crack initiation location observed during experiments. During the experiments it was further observed that the fracture mode corresponds to the load level. It is therefore concluded that to obtain a strong riveted joint with a long fatigue life a balance between design parameters is then needed.
Beskrivning
Ämne/nyckelord
Produktion , Maskinteknik , Production , Mechanical Engineering