Bruddkurver

Bruddkurver are graphs used in fracture mechanics to characterize how cracks behave in materials under mechanical loading. In Danish engineering literature, the term describes curves that relate crack growth and fracture resistance to the applied load, environment and geometry, and are central to assessments of structural integrity and safety.

There are several common types of bruddkurver. Static fracture curves plot parameters such as fracture toughness (K_IC) or critical crack length against applied stress, providing a threshold for the onset of rapid fracture. Fatigue bruddkurver show the rise of crack growth rate (da/dN) as a function of the stress-intensity factor range (ΔK), often described by Paris-type relations. These curves are used to predict the life of a component under cyclic loading and to estimate safe inspection intervals.

Measurement and interpretation typically involve standardized specimens (for example, compact tension or single-edge notch bending tests) and controlled loading, with data fitted to fracture models. Numerical methods and real-world testing are used to derive curves for specific materials, geometries and environments. Bruddkurver are influenced by factors such as material microstructure, temperature, corrosion, and loading rate, which can alter fracture resistance and crack-growth behavior.

Applications include design against brittle or fatigue failure, structural integrity assessments in aerospace, automotive, and civil engineering, and life-extension planning for aging infrastructure. While bruddkurver provide essential insights, they are inherently probabilistic and context-dependent; safe engineering practice combines curve interpretation with material data, service conditions, and appropriate safety factors.