Local strain approach to predict fatigue strength of spot-welded structures.

From the point of view of the objective and scientific design of spot-welded structures, each factor that influences the fatigue strength of the spot-welded structure is quantitatively analyzed using fuzzy mathematics. The weighing coefficient is calculated based on the contribution of each factor and their coupling relationship using DARE method. All the influencing factors are divided to two levels, and quantitative assessment result is obtained. Finally, the fatigue life curve of the spot-welded structure is predicted with the utilization of the fatigue life curve of a standard specimen made of the same material.

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Evaluation of Fatigue Strength of Welded Joints by Local Strain Measurements at Weld Toe

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.348-349.701 ◽

2007 ◽

Vol 348-349 ◽

pp. 701-704

Author(s):

C. Casavola ◽

C. Pappalettere

Keyword(s):

Fatigue Strength ◽

Working Conditions ◽

Welded Joints ◽

Local Strain ◽

Industrial Applications ◽

Welded Structures ◽

Strain Measurements ◽

Weld Toe ◽

Strain Magnitude ◽

The Many

The fatigue strength of real welded structures neither can be covered by formulae or theoretical arguments, nor simply deducted by studying a complex assembly through its elementary components because of the many interactions among different factors governing the phenomenon. In view of this, the support of experimental observations and practical procedures to evaluate the stress/strain magnitude that could lead some components to unsafe working conditions should be preferred, especially in industrial applications where fast and reliable responses are strongly needed.

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Fatigue strength of spot-welded structures Rupp. A., Grubisic, V. and Radaj, D.Materialprufung June 1990 32, (6), 175–179 (in German)

International Journal of Fatigue ◽

10.1016/0142-1123(91)90050-9 ◽

1991 ◽

Vol 13 (2) ◽

pp. 184-184

Keyword(s):

Fatigue Strength ◽

Welded Structures ◽

Spot Welded

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Spot Weldability Assessment of Similar and Dissimilar Steel Sheets for Light Weight Automobile Body

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.306-308.899 ◽

2006 ◽

Vol 306-308 ◽

pp. 899-904

Author(s):

Dong Ho Bae ◽

Won Seok Jung ◽

J.B. Heo

Keyword(s):

Stainless Steel ◽

Fatigue Strength ◽

Lap Joints ◽

Vehicle Body ◽

Rolled Steel ◽

Cold Rolled Steel ◽

Steel Sheets ◽

Automobile Body ◽

Cold Rolled ◽

Spot Welded

An effective way to reduce the weight of vehicle body seems to be application of new materials, and such trend is remarkable. Among the various materials for automobile body, stainless steel sheets and cold rolled steel sheets are under the interests. However, in order to guarantee reliability of new material and to establish the long life fatigue design criteria for body structure, it is necessary to assess spot weldability and fatigue strength of spot welded lap joints fabricated under optimized spot welding condition. In this paper, spot weldability of stainless steel sheets, STS301L and STS304L, and cold rolled steel sheets, SPCC and SPCD. Fatigue strength of lap joints spot welded between similar and dissimilar materials were also assessed.

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Bemessungskonzepte für die Ermittlung der Trag- und Ermüdungsfestigkeit von Reparaturschweißungen/Assessment Concepts for Load Carrying Capacity and Fatigue Strength of Repaired Welded Structures

Bauingenieur ◽

10.37544/0005-6650-2016-01-68 ◽

2016 ◽

Vol 91 (01) ◽

pp. 34-39

Author(s):

Jakob Klassen ◽

Robert Lang ◽

Gerhard Lener

Keyword(s):

Fatigue Strength ◽

Carrying Capacity ◽

Load Carrying Capacity ◽

Welded Structures ◽

Repair Welding ◽

Load Carrying

Im Zuge des CORNET-Forschungsprojektes „REWESTRUCT – Repair welding of structures“ wurden an der Universität Innsbruck, TU Braunschweig und der BTU Cottbus Versuche und numerische Simulationen zur Trag- und Ermüdungsfestigkeit reparaturgeschweißter Verbindungen von Stahlbauteilen durchgeführt.   Dieser Beitrag präsentiert die Auswertung und Ergebnisse der an der Universität Innsbruck und an der Technischen Universität Braunschweig durchgeführten Versuche und Messungen. In Innsbruck wurden an Großbauteilen im Maßstab 1:1 Schwingfestigkeitsuntersuchungen sowie die dazugehörigen strukturmechanischen Berechnungen vorgenommen. In Braunschweig erfolgte die messtechnische Beurteilung der Eigenspannungen mittels Röntgendiffraktometrie sowie deren numerische Berechnung.   Es zeigt sich dabei, dass ordnungsgemäß durchgeführte Reparaturen zu keiner Minderung der Schwingfestigkeit führen. Die im Zuge von Reparaturen durchgeführten Verbesserungen können im Gegenteil auch zu einer Erhöhung der Schwingfestigkeit führen.

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