Diverter damper force analysis and stress intensity factors for its double fillet welds by boundary element method

Abstract

Mechanisms usually transmit power by welded links into a shaft. Should this weld be partial, like fillet welds, there will be an area of stress concentration that could behave like a crack due to sharp corners. These can lead to structural failures due to fatigue. Consequently, to properly design, inspect and maintain these mechanisms it is necessary to use fracture mechanics stress intensity factors. The crack mesh simplicity required by the boundary element method allows easy modeling even for complex geometry. This technique will be used to obtain such parameters for a double fillet weld found in a diverter damper mechanism responsible for controlling hot gas flow to heat recovery steam generator in power plants. But the solutions presented can be used for similar geometrical configurations, specially to shaft link mechanisms. Empirical equations were also obtained to further ease fracture mechanics and fatigue analysis for this kind of geometry.