General- Fatigue Actions (Loading)- Fatigue Resistance- Fatigue Assessment- Safety Considerations- Appendices

Recommendations for Fatigue Design of Welded Joints and Components

Acoustic emission monitoring of fatigue crack propagation

Fatigue analysis of welded joints: state of development

Recent developments in local concepts of fatigue assessment of welded joints

COMMITTEE MANDATE Concern for crack initiation and growth under cyclic loading as well as unstable crack propagation and tearing in ship and offshore structures. Due attention shall be paid to practical application and statistical description of fracture control methods in design, fabrication and service. Consideration is to be given to the suitability and uncertainty of physical models. The work shall be coordinated with that of Committee V.2.

Fatigue and Fracture

Part 1 Welded joints under fatigue loading: Fatigue failure Significant features of welds in relation to fatigue Factors which affect fatigue of welded joints Fatigue of welded joints Conclusions. Part 2 Design rules: Fatigue design rules for welded steel joints Stresses used with the fatigue design rules Significance of weld imperfections Improving the fatigue strength of welded joints Typical service failures.

Fatigue Strength of Welded Structures

In most of the lower fatigue strength welded joints failure occurs by the propagation of a semi-elliptical surface crack which initiates at the weld toe. In order to analyse the progress of these cracks using fracture mechanics techniques, the solution for the stress intensity factor, K, is required. Fatigue cracks in most welded joints adopt shapes which give low a/2c values (up to approximately 0.3) while solutions in the literature are more applicable to a/2c values close to 0.5. Therefore, results in the literature were used to estimate the stress intensity factor for cracks with low a/2c values. Furthermore, the effect of the weld stress concentration factor was incorporated in the solution. The accuracy of the resulting solution was confirmed by using it to determine ΔK values of weld toe cracks for which crack propagation data were available. The results agreed with the expected da/dN vs. ΔK scatterband obtained from centre-notched specimens.

An analysis of fatigue cracks in fillet welded joints

Fatigue Analysis of Welded Components : Designer's Guide to the Hot-Spot Stress Approach

The use of fatigue design rules offers the most effective means of avoiding fatigue failures in welded structures. This chapter outlines the basis of current rules and how they are applied in different specifications, including consideration of residual stresses, size effect, material, welding process and environment. Areas needing further research are highlighted, including adaptation of current rules for use with finite element stress analysis, development of local stress approaches, the treatment of complex loading and cumulative damage calculations.

S. J. Maddox

Papers

Fatigue Strength of Welded Structures

An analysis of fatigue cracks in fillet welded joints

Fatigue Analysis of Welded Components : Designer's Guide to the Hot-Spot Stress Approach

Fatigue design rules for welded structures

Improving the fatigue strength of welded joints by peening.