Stress Intensity Factors For Toe Defects In Single-sided Transverse Attachments Of Varying Thickness Made With Fully Penetrating

TWI Technology Briefing 183-1982

By I J Smith

Background

This report contains the results of finite element calculations giving stress intensity factors for different crack Lengths, loading conditions and attachment thickness ratios for single-sided transverse attachment welded joints. The crack lengths considered range from a/b = 0.01 to 0.20 in steps of 0.01, the attachment thickness ratios are t_a/b = 0.3, 0.4, 0.5 and 0.6 and four different Loading conditions are used, namely uniaxial tension with and without bending restraint, uniform end displacement and pure bending. The results are presented in terms of Y, the normalised stress intensity factor and M_k, the weld correction factor, for the values of a/b considered, in both tabular and graphical form.

Using the results obtained it is predicted that an increase in the attachment thickness will decrease the fatigue strength of the joint and that the effect is approximately the same as increasing the base plate thickness by the same ratio. It is also shown that Mk is only significant below a/b = 0.20 for this geometry and that the different loading conditions all result in approximately the same fatigue strength at 2 x 10⁶ cycles.