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The lack of on-line validation procedures for structure-embedded fiber-optical strain sensors, in particular fiber-Bragg-gratings (FBG), resulted in limited applications in structural health monitoring (SHM). Degradation under service conditions and ageing as a result of climatic influences or delamination under load were unsolved Validation issues. This could be overcome by means of an auto-diagnosis procedure based on FBG-sensors coated by electrochemical deposition (ECD) with a magnetostrictive NiFe-coating on top of an adhesive Cu/Cr adhesive layer deposited by physical vapour deposition (PVD) around the FBG strain sensor. This allows at any time under Service a validation of sensor functionality, stability, and reliability. For this purpose, a magnetic strain-proportional reference field is introduced. The optical read-out is realized by the measurement of the Bragg-wavelength shift.
The ratio of resulting strain and exciting magnetic reference field should be constant given that the sensor is in proper function.
In principle, the magnetostrictive coating around the FBG should also work as on-line magnetic field sensor and other applications in material science. One of these applications is the in-situ monitoring of ECD processes as the deposition of the ECD NiFe-layer on the FBG revealed. Challenges are the monitoring of temperature, deposition
stages/thickness, and resulting mechanical stress under given plating conditions. Monitoring problems can be solved by applying a pre-coated FBG to the electrolytic process as the shift of the Bragg wavelength is affected by both the temperature of the electrolyte near the substrate and the stress formation in the growing layer. The experimental FBG set-up and the quantitative determination of temperature- and stress-related strain are described for a nickeliron
electrolyte. The in-situ measurement of Bragg wavelength shifts of a pre-coated FBG during electrochemical deposition allows a detailed analysis of stress states due to changes in the growth morphology of the layer. The separation of mechanical and thermal contributions to this shift provides information on the individual Deposition processes in terms of a process fingerprint.
The comprehensive knowledge of material properties as engineered and the material behavior in use is of huge importance for the functionality and reliability of processes and products. Hence, the accurate determination of material properties is a prerequisite for the applicability of a given material. Nowadays, macroscopic product features are originated by material properties on the microscopic and nanoscopic scale. This is a general challenge for uncertainty budgets in measurement and testing based on a conformity assesment.
Testing labs accreditated according to DIN EN ISO/IEC 17025 have to meet these demands. This paper focuses on the measurement of physical quantities (measurand with value and unit) and on the testing of material properties (qualitative, semi-quantitative or quantitative characteristics) of solid state materials. For both measurement and testing, the expression of uncertainty according to GUM is essential. Regarding the object/sample one has to subdivide in surface and bulk features, from the measurement/testing point of view destructive vs. nondestructive procedures have to be distinguished. Moreover, direct mesurement/testing and model-based determination of quantities/properties of interest require different approaches regarding the expression of uncertainty. For surface quantities and properties as discussed here, further considerations have to be made with respect to localized (lateral extension, native or artificial) or stratified (homogeneity and isotropy) material features vs. mapping (integration area) and imaging (lateral resolution and field of analysis) specifications of the measurement/testing procedure.
The concept of uncertainty budgets and the expression of uncertainty is introduced and discussed in more detail for the nondestructive model-based determination of thickness by spectroscopic ellipsometry (SE), the destructive determination of adhesion by means of centrifugal adhesion testing (CAT). It is shown that the expression of uncertainty for these examples and real materials requires different approaches resulting in either quantitity values with unit or qualitative/quantititative attributes with calculated/estimated uncertainties in agreement with GUM.
Der Vortrag widmet sich dem „Ringversuch zur Klassifizierung von Kohlenstoffschichten mittels Ellipsometrie“ und beschreibt die experimentellen Eckdaten, die Ellipsometrie als Messmethode am Beispiel DLC auf Stahl, Proben vs. n-k Ebene vs. Ergebnisse des Ringversuches, messtechnische Bewertung des Ringversuches und normative Bewertung des Ringversuches sowie Schlussfolgerungen.
Der Stand der Normung im Bereich der Oberflächentechnik wird zusammengefasst. Aktuelle Normungsvorhaben zur chemischen Oberflächenanalyse, Rastersondenmikroskopie, Nanotechnologie, Oberflächenmesstechnik im Mikro- und Nanobereich, für Anwendungen von Kohlenstoffschichten sowie von Mess- und Prüfverfahren für metallische und anorganische Überzüge werden vorgestellt. Ein Ringversuch zur Klassifizierung von Kohlenstoffschichten mittels Ellipsometrie wird diskutiert. Abschließend wird das DIN-Terminologie Portal erläutert.
Der Vortrag widmet sich Haftung und Haftfestigkeit bezüglich Grundlagen, Einflussgrößen sowie Prüfverfahren und beschreibt die Punkte: Generische und spezifische Motivation, Einflussgrößen auf Haftfestigkeit und Haftung von Beschichtungen, Prüfverfahren zur quantitativen Bestimmung der Haftfestigkeit und zur qualitativen Klassifizierung bzw. semi-quantitativen Bewertung der Haftung im Einzelnen.
Der Vortrag widmet sich der „Quantifizierung der Festigkeit von Kunststoffklebungen & -beschichtungen: Vorbehandeln, Kleben und Prüfen im OKTETT“ und beschreibt das Mehr-Proben-Konzept zur Herstellung und Prüfung von Klebeverbunden. Vorgestellt werden die Mehr-Proben-Klebevorrichtung sowie die Centrifugal Adhesion Testing (CAT) Technologie zur Bestimmung der Haft- und Klebefestigkeit von Beschichtungen (Al auf PP, SiO2 auf CR39).