Scheurlengte

Scheurlengte, in Dutch fracture mechanics, refers to the length of a crack within a material or component. It is a key measure used to assess the integrity of structures and to predict failure under load. The term covers both surface cracks and through-thickness cracks, and it may denote either the current crack length observed or the critical crack length at which fracture is expected to occur under given loading.

In practice, scheurlengte is determined by nondestructive testing and, when possible, supplementary fracture analysis. Methods include visual inspection for surface cracks, dye penetrant testing, magnetic particle inspection, radiography or computed tomography imaging, ultrasonography, and eddy current testing. The measured crack length can be reported as the maximum dimension, the length along the crack front, or as an effective length accounting for geometry.

The crack length is related to fracture mechanics parameters such as the stress intensity factor K and fracture toughness K_IC. For fatigue, crack growth follows empirical laws (da/dN = C (Delta K)^m), with the crack length increasing as cycles accumulate. The critical crack length is reached when K equals K_IC, at which point rapid fracture may occur. Scheurlengte is also used in design and inspection standards to determine allowable acceptances, maintenance intervals, and safety margins.

Limitations include uncertainties due to complex crack shapes, branching, and multi-crack interaction; measurements may be affected by surface condition and access, and through-thickness cracks can be difficult to quantify from surface data.

See also fracture mechanics, K_IC, nondestructive testing, fatigue crack growth.