Stress Measurements in Glass and Plastic by Optical Hole-Drilling

Abstract:

Quantitative residual stress depth profile measurements are common in metallic parts but not in glass or plastic. This paper describes some experimental stress depth profile measurements using hole-drilling with electronic speckle pattern interferometry (ESPI) in two types of glasses and two thermoplastics. Stress depth profiles in laminated and toughened glass specimens show the expected low stresses in the former and significant compressive stresses near the surface in the latter for the as-is condition. The stress curves shift towards tensile stresses during slight bending deformation, as expected. The bending devices initially used for experiments with Bayblend® and Makrolon® were deforming the specimens too severely to allow proper, static, measurements. Significant stress reductions due to creep were measured for extended bending times. Subsequent measurements for less severe bending show similar stress curve characteristics. Residual stresses in the as-is condition apparently account for some of the differences to the predicted bending stress profile.

• Periodical: Materials Science Forum (Volumes 768-769)
• Pages: 95-100
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.768-769.95
• Online since: September 2013
• Authors: Markus Laakkonen, Theo J. Rickert, Lasse Suominen
• Keywords: Bayblend, Electronic Speckle Pattern Interferometry (ESPI), Laminated Glass, Makrolon, Optical Hole-Drilling, PRISM, Residual Stress, Stress Measurement, Toughened Glass

References

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