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- 2014 (13) (entfernen)
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- Vortrag (6)
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Schlagworte
- Fatigue strength (3)
- Fracture mechanics (3)
- Crack propagation (2)
- Flaw assessment (2)
- Short cracks (2)
- Weldments (2)
- (Residual) lifetime (1)
- Biaxial tensile loading (1)
- Critical speed (1)
- Fatigue crack propagation (1)
- Flawed rotors (1)
- Fracture toughness (1)
- Korrosion (1)
- Limit load (1)
- Nichtmetallische Einschlüsse (1)
- R6 procedure (1)
- Radsatzwellen (1)
- Reference load (1)
- Residual stresses (1)
- Schadenstoleranz (1)
- Schwingfestigkeit (1)
- Sichere Lebensdauer (1)
- Steinschlag (1)
- Strength mismatch (1)
- SN curve (1)
- Zerstörungsfreie Inspektion (1)
Eingeladener Vortrag
- nein (6)
Recently two of the authors of the present paper proposed a model for a fracture mechanics
based prediction of the S–N characteristics of metallic components with large microstructural
defects and supported this by a validation exercise on tensile plates made of an aluminium
alloy AL5380 H321. Here the authors extend the study using a number of further
data sets from the literature for which data were available at different R ratios. These data
include two aluminium alloys, Al 2024-T3 and Al 7075-T6, and a ductile cast iron, EN-GJS-
400-18-LT. Despite of necessary assumptions for the compensation of partially missing
input information the results were fairly reasonable with the exception of one data set.
The authors identify high applied stress levels in combination with potential multiple crack
initiation as the probable root of the problem and propose a scheme how the model can be
extended for taking into account crack initiation.
Die Sicherheit von Radsatzwellen beruht gegenwärtig auf zwei Säulen: der Schwingfestigkeitsauslegung und periodischen Inspektionen. Ausgehend von einem Schadensfall, der gebrochenen ICE 3-Welle von Köln, 2008, werden ausgewählte Aspekte dieser beiden Säulen diskutiert und Vorschläge zur weiteren Verbesserung gemacht. Diese betreffen u. a. Fragen einer Betriebszeitbegrenzung, Veränderungen der Schwingfestigkeit während des Betriebs infolge von Korrosion und Steinschlag, den Einfluss von Korrosion auf Schwingrissinitiierung und -fortschritt, den potenziellen Einfluss nichtmetallischer Einschlüsse auf die Schwingfestigkeit, die Möglichkeiten, sie im Rahmen der Qualitätssicherung zu detektieren, sowie Fragen der Bruchmechanik und der Zuverlässigkeit zerstörungsfreier Schwingriss-Prüfverfahren im Rahmen eines Konzepts regelmäßiger Inspektionen.
Welding is one of the most common methods in industrial practice for joining components. Its main advantages are high speed in manufacturing combined with low costs and, usually, a high degree of flexibility, integrity and reliability. Nevertheless, welding is a highly complex metallurgical process and, therefore, weldments are susceptible to material discontinuities, flaws and residual stresses which may lead to structural failure and life time reduction. As a consequence weldments are an important field of fracture mechanics methods although its application is more complex than for homogeneous or non-welded structures. The aim of the paper is to provide an overview on the current state of fracture mechanics application to weldments. It starts by discussing the specific features which any fracture mechanics analysis of weldments has to take into account. Then, the experimental determination of fracture toughness, fatigue crack propagation and tensile properties of weldments is addressed. Finally, the analytical determination of the crack driving force in components and structural integrity assessment approaches for weldments are presented.
The idea to determine the fatigue strength of weldments by means fracture mechanics was originally based on the empirical observation that the major portion of the fatigue life in weldments is frequently spent in crack propagation. The present paper gives a brief overview on the basic principles of fracture mechanics-based determination of fatigue strength and on special features which have to be considered for weldments. Based on this information, the ongoing research project IBESS is introduced and briefly reviewed.
The Fatigue Crack Propagation threshold as a design criterion - actual developments and open issues
(2014)
The idea to determine the fatigue strength of weldments by means fractuie mechanics was originally based on the empirical observation that the major portion of the fatigue life in weldments is frequently spent in crack propagation. The present paper gives a brief OverView on the basic principles of fracture mechanics-based determination of fatigue strength and on special features which have to be considered for weldments. Based on this Information, the ongoing research project IBESS is introduced and briefly reviewed.