Präsentation
Filtern
Erscheinungsjahr
- 2017 (4) (entfernen)
Dokumenttyp
- Vortrag (4)
Sprache
- Englisch (4)
Referierte Publikation
- nein (4)
Schlagworte
- Safety (4) (entfernen)
Eingeladener Vortrag
- nein (4)
Non-Destructive Testing (NDT) is routinely used in aerospace, nuclear, railway and automotive industries. The most common use of NDT is to find flaws in components. In dynamically loaded components, flaws grow, and if they are not detected in time and no corrective measures are taken they can reach critical sizes. When a flaw reaches a critical size, it endangers the structural integrity of the component and will likely cause the component to fail. To detect flaws before they reach a critical size, components are inspected in fixed time intervals with non-destructive testing systems. In order to determine the amount of time between inspections, three variables are necessary: the critical size of the flaw, the flaw propagation speed and the size of the flaw that can be reliably detected by NDT. All three variables are, to a certain extent, stochastic. The critical size of the flaw and flaw propagation speed are questions of fracture mechanics. The size of the flaw that can be reliably detected by NDT is predicted by POD curves. The POD is determined for a given inspection scenario. The inspection scenario includes the NDT system, the component geometry and the type of the flaw. If one of these changes, the POD will also change and needs to be recalculated. As a result, the design of a dynamically loaded safety-relevant components is an iterative process in which a geometry is sought that provides an optimum between structural integrity and inspectability. A model that describes the iterative process for the design of the safe components with examples from praxis will be presented.
This presentation mentions the most important safety items that should be improved from the perspective of Germany.
These are the improvement of the understanding and definition of term "safety", the agreement on procedures for the measurement of safety and the issue of degradation in combination with the safety level to be ensured until end of life.
For using probabilistic experience for the whole production adequate measures for surveillance of the production should additionally become mandatory to be taken into account.
The essential aspects of these issues are shortly explained and highlighted by especially aspects of the slow burst testing with respect to non-cycle fatigue sensitive designs and the hint on the general scatter of properties (Monte-Carlo simulation).