In order to clarify the influence of weld defects on fatigue properties and the acceptable defect size in girth welds of gas pipelines under earthquake conditions, very low cycle fatigue tests and fatigue life estimation by fracture mechanics analysis of butt welded joints containing defects were carried out. lt was experimentally recognized that fatigue life is considerably affected by defect size and it decreases with the increase of equivalent crack size. Moreover the fatigue crack propagation rate is related to the J-integral range and the relationship is almost equal to the extension of that in the low J-integral range region. The analytical results show that the fatigue life with a surface defect is shorter than that with a buried defect and the fatigue life decreases with the increasing plate thickness from 9mm to 19mm when the ratio of defect size to thickness is constant. The acceptabie defect size in girth welds of gas pipelines under the earthquake conditions prescribed by the Japan Gas Association, namely, the strain amplitude of 0.5% for 50 cycles of cyclic displacement, is proposed as a result of the investigation.
Influence of weld deffects on very low cycle fatique properties of welded joints
Einfluss der Schweißfehler auf die Ermüdungseigenschaften von Schweißverbindungen bei sehr niedrigen Lastspielzahlen
2001
8 Seiten, 12 Bilder, 2 Tabellen, 20 Quellen
Conference paper
English
Fatique strength of friction welded joints.
Automotive engineering | 1975
|Fatique assessment of aluminium welded components
Automotive engineering | 1999
|Very high cycle fatique of cast aluminium alloys under variable humidity levels
Automotive engineering | 2015
|High-temperature, low-cycle fatique behavior of tantalum
TIBKAT | 1971
|