Bending Fatigue Strength and the Effect of Assembling Stress on Fillet Welded Joints of Catalyst Muffler Flange Pipes

Oh, Gyoko

doi:10.20485/jsaeijae.8.2_87

Cited by 6 publications

(1 citation statement)

References 5 publications

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“…The bending moment amplitude was calculated from load W and span distance L , and nominal stress amplitude was defined as the value divided by section modulus of the columnar bolt cross section or that of the screw valley cross section in the bolt-only sample. 12,13 There were some differences between the bolt under-head and the screw such as their diameters and curvature radiuses of the corner position, the size effect and stress concentration and so on that should be taken into consideration. Consequently, it was appropriate for the strength of the samples to have been compared relatively with each other here.…”

Section: Experimental Methodsmentioning

confidence: 99%

Bending fatigue behaviour and microstructure in welded high-strength bolt structures

Oh¹,

Akiniwa

2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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Welded high-strength bolts are recently being applied to automobile part fixations, and it is important to clarify their fatigue behaviours and to carry out the fatigue strength designs for preventing fatigue failures. Using the spot and full-circled welded bracket samples in four kinds of weld shapes, bending fatigue strength properties of welded high-strength bolt structures were examined. Factors affecting fatigue to failure, such as weld bead shapes and metal structures, were identified through local stress measurements with strain gauges and X-ray diffractions, microscope observations and chemical composition analyses, as well as stress concentrations of finite element method computational simulation. Differences of bending fatigue strengths at 2 × 105 cycles in welded bolt structure samples when based on nominal stress are 15% to 60% compared with the bolt itself. Fatigue strengths corresponded to four kinds of fracture modes and did not decline greatly in the full-circled welded structure. The spot P sample, in which the connecting line between the two centres of the weld beads was perpendicular to the load direction, has higher strength due to the crack initiating from the weld zone of the gap between the plate and the bolt flange which has hard mixed phases of ferrite + martensite + bainite with high fatigue resistance, and its strength divided by weld length does not deteriorate. The strengths and fracture modes were analysed from the viewpoints of the shape effect relating to the stress concentration and residual stress and the material effect relating to the microstructure of the weld as well.

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Section: Experimental Methodsmentioning

confidence: 99%