Reliability of critical welded joints in responsible support structures of bucket wheel excavator

Abstract

Structural reliability and integrity include analysis of state, diagnostics of structural behaviour and compliance, life assessment and revitalization of structures. Aside to assessment based on flaws detected by non-destructive methods, these disciplines also include stress state analysis. Detailed distributions of displacement, deformation and stress are acquired determining “weak” locations. This approach is important for structures exposed to complex dynamical loads as bucket wheel excavators. Fatigue research deals with welded joints as critical locations in welded structures. Under variable loads, stress concentration effects are pronounced not only by geometry and shape, but also by flaws. Flaws originate in design and construction, or in the technology, inspection and testing. Multiple parameters become critical compared to base material. Reliability is observed with more complexity as the probability of proper functionality of responsible welded joints in prescribed working conditions and operating life. The relationship between probability of failure and the degree of overlapping and shape of critical and working stress spectra are clarified and enable reliability determination in responsible welded joints.