Strain Measurement within Thin Fibers based on Subjective Laser Speckle Patterns
Sprache des Vortragstitels:
7th International Conference on Sensors and Electronic Instrumentation Advances (SEIA' 2021)
Sprache des Tagungstitel:
The measurement of stress-strain curves of fibers poses a challenging task, since commonly used contacting techniques are not applicable. Therefore, we propose to employ a laser-speckle extensometer with a sufficiently high displacement resolution to be able to even derive strain values of the rather very stiff structural fibers. Due to the properties of laser speckle patterns stemming from fibers, they are especially well suited for the task. In order to measure the stress-strain curve one has to estimate local displacements between strained and initial loading for two surface elements separated by the base length the strain is to be determined over. This is a formidable task in itself, since shifts in the range of only 1/100 of the pixel pitch have to be resolved in order to enable the characterization of a wide range of different biological and technical fibers.