Flächige und zerstörungsfreie Qualitätskontrolle mittels spannungsoptischer Methoden

Feldmann, Markus; Kasper, Ruth; Biase, Pietro Di; Schaaf, Benjamin; Schüler, Christian; Dix, Steffen; Illguth, Marcus

doi:10.1002/cepa.27

Cited by 6 publications

(6 citation statements)

References 4 publications

(2 reference statements)

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“…In the framework of the investigations, two full-field methods are selected to analyze residual stresses at holes near edges. The first method A, the RGB photoelasticity according to Ajovalasit et al [15], Illguth et al [16], Dix et al [17] and [18] is used to verify the suitability of the second method B, the half-fringe or half-wavelength method of the measuring device Line Scanner (by Softsolution GmbH) for this investigation. Both methods are similar, as both are calibrated circular polariscopes [19,20].…”

Section: Full-field Methodsmentioning

confidence: 99%

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Analysis of residual stresses at holes near edges in tempered glass

et al. 2021

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Point-fixed glazings of tempered glass are popular in facade and roof constructions. The distances from the hole to the glass edge specified in DIN 18008 are restrictive for many designers and should be reduced from an aesthetic point of view. However, if the specified distances are not reached, only the strength of the basic glass can be applied according to the standard. In the presented paper, residual stresses at holes near the edges of tempered glass are analyzed experimentally. For this purpose, photoelastic measurements and four-point bending tests are carried out on a series of modified standard specimens with different edge distances and hole diameters. The results of the investigation show that the depth of the residual stress zones, hole and edge, are significantly influenced by the glass thickness and the hole diameter. In addition, it was shown that the characteristic bending strength of these tempered glass panes with near-edge holes was achieved for almost all test series.The achieved results could lead to a reduction of the edge distances of holes in tempered glass in the future standard.

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Section: Full-field Methodsmentioning

confidence: 99%

“…They differ fundamentally only in the used light sources. Method A applies a white light source in the dark field setup and method B uses several individually triggerable monochromatic light sources in the bright field configuration [17,21]. Both methods are intended to detect and measure the width of influence of zone 4 w zone 4 .…”

Section: Full-field Methodsmentioning

confidence: 99%

Analysis of residual stresses at holes near edges in tempered glass

et al. 2021

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“…Dabei handelt es sich um schwarzweiße bis hin zu farblichen Mustern, die aufgrund der doppelbrechenden Eigenschaften von Glas erkennbar werden. Aktuelle Forschungsergebnisse zu optischen Anisotropie-Effekten werden in [1,2,3] beschrieben.…”

Section: Einleitung Und Motivationunclassified

Statistische Charakterisierung der Druckzonentiefe vorgespannter Gläser

et al. 2022

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Infolge variierender Produktionsbedingungen erfolgt der thermische Vorspannprozess von Gläsern nicht vollständig homogen. Daraus entstehen lokale Unterschiede in den Eigenspannungen. Um die statistischen Verteilungen von charakterisierenden Größen des Eigenspannungsprofils in thermisch vorgespanntem Flachglas zu bestimmen, wurden mehr als 100 Proben mit einem Streulicht‐Polariskop (SCALP) untersucht. Die Messungen wurden an zuvor definierten Stellen in drei Richtungen an beiden Oberflächen der Probekörper durchgeführt. Dies ermöglicht die quantitative Auswertung und Kalibrierung statistischer Modelle der Druckzonentiefe sowie der Homogenität der Vorspannungsprofile. Statistical characterization of compression zone depth in pre‐stressed glasses. Due to varying production conditions, the thermal tempering process of glass is not fully homogeneous. This results in local differences in the residual stresses. In order to determine the statistical distributions of characterizing quantities of the residual stress profile in thermally toughened flat glass, more than 100 samples were examined with a scattered light polariscope (SCALP). The samples were examined at previously defined locations from both surfaces in three directions with respect to the pre‐stress profiles. This allows the quantitative evaluation and calibration of statistical models of the compression zone depth and the homogeneity of the prestress profiles.

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“…Durch die Farben kann auf die optischen Gangunterschiede geschlossen werden. So erscheinen beispielsweise die Isochromaten bei einer Hauptspannungsdifferenz von 0 schwarz [11,14,18].…”

Section: Qualitative Untersuchungen Mittels Polfilterunclassified

Punktgehaltene Gläser mit geringem Bohrungsrandabstand

2022

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In der Praxis wird der Abstand vom Bohrungsrand zur Glaskante nach DIN 18008‐3 bei punktgehaltenen Verglasungen häufig unterschritten, sodass nach Norm nur die Festigkeit des Basisglases angesetzt werden darf. Gemäß aktuellen Untersuchungen werden die Verteilung der Eigenspannungen und die charakteristische Biegefestigkeit bei Verringerung des Randabstandes zur Bohrung nicht relevant beeinträchtigt. Dies kann auch anhand eines Praxisbeispiels einer Aufzugverglasung aus ESG mit randnahen Bohrungen verifiziert werden. Hier wird mit spannungsoptischen Messungen die Vorspannqualität des Glases untersucht. Abschließend werden Bruchspannungen aus verschiedenen zerstörenden Versuchen an randnahen Bohrungen miteinander verglichen. Point‐supported glasses with small distance from hole to edge from the point of view of science and application. In point‐fixed glazing, the distance from the hole to the edge according to the German standard DIN 18008 is often undercut. So that according to the standard, only the strength of the base glass can be applied. Current investigations show that the distribution of residual stresses and the characteristic bending strength are not significantly affected by reducing the distance from edge to hole. This is verified by means of a field example of a lift glazing with holes close to the edge in toughened safety glass. Here, the pre‐stressing quality of the glass is examined with photoelastic measurements. Finally, fracture stresses from various destructive tests on holes near the edges are discussed.

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Flächige und zerstörungsfreie Qualitätskontrolle mittels spannungsoptischer Methoden

Cited by 6 publications

References 4 publications

Analysis of residual stresses at holes near edges in tempered glass

Analysis of residual stresses at holes near edges in tempered glass

Statistische Charakterisierung der Druckzonentiefe vorgespannter Gläser

Punktgehaltene Gläser mit geringem Bohrungsrandabstand

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