Portable Piezospectroscopy system: non-contact in-situ stress sensing through high resolution photo-luminescent mapping

    Authors

    I. Hanhan; E. Durnberg; G. Freihofer; P. Akin;S. Raghavan

    Comments

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    Abbreviated Journal Title

    J. Instrum.

    Keywords

    Spectrometers; Detection of defects; Data processing methods; THERMAL BARRIER COATINGS; CHROMIUM-DOPED SAPPHIRE; RESIDUAL-STRESS; OXIDATION STRESSES; FLUORESCENCE; SPECTROSCOPY; CALIBRATION; MICROPROBE; EVOLUTION; ALUMINA; Instruments & Instrumentation

    Abstract

    Through the piezospectroscopic effect, certain photo-luminescent materials, once excited with a laser, produce spectral emissions which are sensitive to the stress or strain that the material experiences. A system that utilizes the piezospectroscopic effect for non-contact stress detection over a material's surface can capture important information on the evolution of mechanical response under various conditions. Therefore, the components necessary for piezospectroscopic mapping and analysis have now been integrated into a versatile and transportable system that can be used with photo-luminescent materials in any load frame or on a variety of structures. This system combines compact hardware components such as a portable laser source, fiber optics, spectrograph, charge-coupled device (CCD), and an X-Y-Z stage (with focusing capabilities) with a series of data analysis algorithms capable of analyzing and outputting high resolution photo-luminescent (PL) maps on-site. Through a proof of concept experiment using a compressed polycrystalline alumina sample with sharp machined corners, this system successfully captured high resolution PL maps with a step size of 28.86 mu m/pixel and located high stress concentrations in critical areas, which correlated closely with the results of a finite element model. This work represents an important step in advancing the portability of piezospectroscopy for in-situ and non-contact stress detection. The instrumentation developed here has strong implications for the future of non-destructive evaluation and non-invasive structural health monitoring.

    Journal Title

    Journal of Instrumentation

    Volume

    9

    Publication Date

    1-1-2014

    Document Type

    Article

    Language

    English

    First Page

    11

    WOS Identifier

    WOS:000345026000019

    ISSN

    1748-0221

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