Paper
30 June 1998 Investigation of laser welds by means of digital speckle photography
Daniel Holstein, Hans-Juergen Hartmann, Werner P. O. Jueptner
Author Affiliations +
Abstract
The introduction of laser beam welding into industry requires an extended knowledge about the weld seam properties. This is a standard procedure for all welding methods. However, the geometry of laser welds significantly differs from the geometry of conventional welds. Narrow dimensions of the heat affected zone and the weld material are characteristic for laser welds and cause high gradients of the laser weld properties, e.g. the yield strength. In order to determine experimentally the real local material properties of each zone of the laser weld an adapted measurement technique with a high lateral resolution is required. Conventional methods, like strain gauges, are not able to provide this information due to the lack of local resolution. The digital speckle photography, presented in this work, is a rather new optical measurement technique that fulfills the resolution requirement. Furthermore, this method evaluates electronically displacements and strains in a wide measurement range up to the failure of the investigated sample. Experimental results obtained by means of digital speckle photography show that this is an excellent method for fieldwise displacement and strain determination, respectively. The characteristic 'overmatching' effect of laser welded steel samples, that is the significantly higher yield strength of the weld material in comparison to the base material, is presented on the basis of experimentally determined stress/strain diagrams.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Daniel Holstein, Hans-Juergen Hartmann, and Werner P. O. Jueptner "Investigation of laser welds by means of digital speckle photography", Proc. SPIE 3478, Laser Interferometry IX: Techniques and Analysis, (30 June 1998); https://doi.org/10.1117/12.312948
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Cited by 2 scholarly publications.
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KEYWORDS
Digital signal processing

Digital photography

Speckle

Photography

Correlation function

Speckle pattern

Failure analysis

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