The paper presents methods for determining the fatigue life of welded joints with particular emphasis given to typical joints. In addition, the article presents various possible nominal stress-based ways enabling the calculation of stresses, including structural stresses and involving the most complex linear fracture mechanics. The paper also discusses recommendations by the International Institute of Welding related to the determination of the fatigue life of welded joints in flat elements exposed to tension-compression conditions. The work is focused on assessing the fatigue life of welded joints (selected types) in accordance with the guidelines specified in related recommendations issued by the International Institute of Welding and taking into consideration the analysis concerned with the safety of such structures.
PL
Przedstawiono metody wyznaczania trwałości zmęczeniowej złączy spawanych ze szczególnym uwzględnieniem typowych złączy. Podano możliwe sposoby wyznaczania naprężeń uzyskanych na drodze obliczeniowej w złączach spawanych na podstawie naprężeń nominalnych według różnych propozycji, poprzez naprężenia strukturalne, aż po zastosowanie najbardziej skomplikowanej liniowej mechaniki pękania. Na tym tle przedstawiono zalecenia Międzynarodowego Instytutu Spawalnictwa dotyczące wyznaczania trwałości zmęczeniowej złączy spawanych w warunkach rozciągania-ściskania elementów płaskich. Skupiono uwagę na problemie oceny trwałości zmęczeniowej połączeń spawanych wybranych typów złączy zgodnie z wytycznymi zawartymi w zaleceniach Międzynarodowego Instytutu Spawalnictwa oraz analizie bezpieczeństwa takich konstrukcji.
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The article discusses the effect of the, determined by tensile test, non-linear characteristics of AlSi alloys on the value of the shape factor k for the three different sizes of the radius of the ring notch made on round specimens. Applying a numerical solution, the changes of stress in the notch plane were determined in function of the notch configuration and the value of instantaneous load. Tensile tests were carried out on round bars with ring notches. The appearance of fractures was examined on scanning images. Differences in notch effect observed in the linear-elastic and elastic-plastic model of material hardening in a non-linear mode were described.
Sintered alloy steels are needed for mostly PM structural parts. Powder metallurgy techniques provide a means of fabricating high quality steel parts with tailored mechanical properties. It is now possible to produce sintered steel parts with properties equal to and even superior to those of parts made by more traditional routes. Challenges arise both with the material selection and component fabrication. This presentation outlines the processing for high performance structural application.
The powder metallurgy route may allow sintered manganese steels to be made based on pure iron powder and ferromanganese powder with control over alloy microstructure. The factors that contribute to the mechanical properties of sintered Fe-3%Mn-0,8%C manganese steel, such as the sintering atmosphere, dew point, sintering temperature, cooling rate are summarized. The paper shows the influence of these parameters on the tensile strength, yield strength, transverse rupture strength, impact strength and hardness. It showed that tensile high strength level higher then those of many present sintered steels can be obtained already in the as-sintered condition.
Results of investigation of silicon additions and processing parameters on mechanical properties and microstructure of the iron-base sintered materials are presented. Green density as well as as-sintered density, hardness, tensile strength, transverse rupture strength and impact toughness were measured. As-sintered microstructures were also examined. The results indicate marked effect of silicon additions, cold compacting pressure and sintering temperature on evaluated properties.
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