Effect of loading type on the fatigue strength of asymmetric and symmetric transverse non‐load carrying attachments

Abstract

This study considers the effect of bending loading and the symmetry of joints on the fatigue strength of transverse non‐load carrying attachments. Conventionally, the fatigue strength of a welded joint has been determined without taking these factors into account. Experimental and finite element analyses were carried out and both methods showed that both loading type and symmetry have an influence on the fatigue resistance of a welded joint. Under tensile loading, the fatigue strength of asymmetric T‐joints was higher than that of symmetric X‐joints. Respectively, the fatigue resistance of tested joints improved explicitly when the external loading was bending. The finite element analysis was in good agreement with the test results in the joints subjected to tension but gave very conservative results in the joints subjected to bending.

Fatigue strength assessment of ultra-high-strength steel fillet weld joints using 4R method

“…Although UHSS fillet weld joints have been widely studied experimentally in recent years, geometry (weld profiles and weld toe radii) or residual stress measurements have not been conducted or reported precisely enough to apply the fatigue test data in the fatigue analyses using the 4R method. Consequently, experimental fatigue test data of UHSS fillet weld joints, reported in [17,30], are used as a basis of the fatigue analysis and in addition, fatigue tests in the AW and HFMI-treated condition are carried out for non-load-carrying X-joints (NLCX) made of S1100 UHSS grade to supplement the fatigue test data. The NLCX-joints in the AW condition are fatigue tested using R = 0.1 and R = 0.5 applied stress ratios of external loading.…”

Fatigue Performance of GMA-Brazed Non-load Carrying Joints Made of Ultra-High-Strength Steel

“…Generally, various materials and weld quality are covered in S-N curves of codes and guidelines and consequently it is more reasonable to compare obtained results with similar welded NLC X-joints. Available fatigue data of GMA-welded joints made of S960 MC originally reported in [21][22][23] were selected for comparison. The tests in [21][22][23] were carried out for normal quality welds, i.e.…”

“…Available fatigue data of GMA-welded joints made of S960 MC originally reported in [21][22][23] were selected for comparison. The tests in [21][22][23] were carried out for normal quality welds, i.e. weld toe radius r < 1 mm and without post-weld treatment.…”

“…(2), and thus the S-N curve converges with the computational mean S-N curve of the IIW Recommendations. The fatigue test data of the GMAwelded specimens in [21][22][23] are plotted with the test results of this study in Fig. 7.…”

Fatigue strength assessment of duplex and super-duplex stainless steels by 4R method

“…1, the membrane Δσm and bending stress range Δσb components can be defined based on the type of load, the joint geometry, and the misalignments. The notch stress concentration factors (SCFs) due to the local weld (and joint) geometry are calculated for the membrane (Kt,m) and bending stress ranges (Kt,b) separately, as introduced by Ahola et al [17]. The calculations are carried out using the ENS method and considering the weld quality by adjusting the weld toe radius r = rtrue + 1 mm.…”