FATIGUE IN WELDED METAL STRUCTURES: AN INTRODUCTORY REPORT TO A RESEARCH PROGRAMME

FATIGUE DES OUVRAGES D'ART METALLIQUES SOUDES: RAPPORT INTRODUCTIF A UNPROGRAMME DE RECHERCHE

Welded metal structures may in some cases crack under the effect of traffic loads. This fatigue damage is very infrequent, but it deserves study, because it occurs mainly at the welds and the geometrical discontinuities of the structure. The first section of this bibliographic review includes general remarks on the importance of the problem of fatigue in welded metal structures. Section II reveiws the mathematical and physical theories of damage. The notions of lifetime and endurance of the parts subjected to fatigue are also dealt with, and the characteristics Wohler's and Goodman-Smith's diagrams are given. The mechanisms of cracking make it possible to interpret the propagation laws of cracks, while the fracture mechanics determine the maximum depth of these cracks and hence the lifetime of life of the elements subjected to fatigue. Methods of fatigue testing may use either numerous small samples making it possible to pin down certain parameters influencing behaviour under fatigue, or a very small number of large samples. The results of tests are made use of by statistical probability methods, expressed in analytical mathematical laws if simplifying assumptions are adopted. Section III indicates the points in a metal structure carrying traffic which are most liable to risks of fatigue damage. Section IV examines the influence of the characteristics of welded joints on the behaviour of assemblies under fatigue. These characteristics are either of a geometric nature, including porosity, blisters, and defects such as lack of fusion, or of metallurgical origin. Correlatively, ways of improving the behaviour of welded joints under fatigue are indicated. In conclusion, it deals with the representativity of tests on samples in experimental procedures designed to predict the behaviour of a structure under fatigue. /Author/

  • Corporate Authors:

    Central Laboratory of Bridges & Highways, France

    75732 Paris,   France 
  • Authors:
    • Brevet, P
    • Francois, D
    • Gourmelon, J P
    • RAHARINAIVO, A
  • Publication Date: 1978-11

Language

  • French

Media Info

  • Features: References; Tables;
  • Pagination: 63 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00189336
  • Record Type: Publication
  • Report/Paper Numbers: Res Rept LPC No. 85
  • Files: TRIS
  • Created Date: Mar 28 1979 12:00AM