DE4128233A1 - Measuring strength of glass and ceramics - using image processing method having measuring windows - Google Patents
Measuring strength of glass and ceramics - using image processing method having measuring windowsInfo
- Publication number
- DE4128233A1 DE4128233A1 DE19914128233 DE4128233A DE4128233A1 DE 4128233 A1 DE4128233 A1 DE 4128233A1 DE 19914128233 DE19914128233 DE 19914128233 DE 4128233 A DE4128233 A DE 4128233A DE 4128233 A1 DE4128233 A1 DE 4128233A1
- Authority
- DE
- Germany
- Prior art keywords
- dark
- light
- measuring
- fracture
- hertz
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000011521 glass Substances 0.000 title claims abstract description 9
- 239000000919 ceramic Substances 0.000 title claims abstract description 5
- 238000003672 processing method Methods 0.000 title claims abstract 3
- 238000000034 method Methods 0.000 claims abstract description 17
- 230000007704 transition Effects 0.000 claims abstract description 10
- 239000006112 glass ceramic composition Substances 0.000 claims abstract description 4
- 238000005259 measurement Methods 0.000 claims description 12
- 239000000463 material Substances 0.000 claims description 5
- 230000015572 biosynthetic process Effects 0.000 claims description 3
- 238000012935 Averaging Methods 0.000 claims description 2
- 238000011835 investigation Methods 0.000 claims description 2
- 238000007373 indentation Methods 0.000 description 4
- 238000012545 processing Methods 0.000 description 3
- 230000009191 jumping Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 1
- 230000005670 electromagnetic radiation Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 230000005693 optoelectronics Effects 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/38—Concrete; Lime; Mortar; Gypsum; Bricks; Ceramics; Glass
- G01N33/388—Ceramics
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/40—Investigating hardness or rebound hardness
- G01N3/42—Investigating hardness or rebound hardness by performing impressions under a steady load by indentors, e.g. sphere, pyramid
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/38—Concrete; Lime; Mortar; Gypsum; Bricks; Ceramics; Glass
- G01N33/386—Glass
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/006—Crack, flaws, fracture or rupture
- G01N2203/0062—Crack or flaws
- G01N2203/0066—Propagation of crack
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/0641—Indicating or recording means; Sensing means using optical, X-ray, ultraviolet, infrared or similar detectors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0682—Spatial dimension, e.g. length, area, angle
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Biochemistry (AREA)
- Physics & Mathematics (AREA)
- Analytical Chemistry (AREA)
- Ceramic Engineering (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
Description
Die Erfindung betrifft ein Verfahren zur objektivierten Ermittlung von Festigkeit und bruchmechanischen Kennwerten von Gläsern sowie keramischen und glaskeramischen Werkstoffen. Sie beruht auf dem Verfahren der Kugeleindruckmethode und dient zu deren objektivierter Auswertung. Anwendung findet sie bei der Prüfung aller Werkstoffe an denen die Kugeleindruckmethode durchgeführt werden kann. Voraussetzung ist, daß es sich um Werkstoffe handelt, welche für Bereiche elektromagnetischer Strahlung durchlässig sind und ein entsprechender Sensor zur Aufnahme des HERTZschen Kegelbruchs zur Verfügung steht.The invention relates to a method for objectified Determination of strength and mechanical properties of Glasses as well as ceramic and glass-ceramic materials. they is based on the ball indentation method and serves their objectified evaluation. It is used in the Testing of all materials using the ball indentation method can be carried out. The prerequisite is that it is Materials that are used for areas of electromagnetic Radiation are permeable and a corresponding sensor for Recording of the HERTZ cone fracture is available.
Die bisher zur Anwendung kommende mikroskopische Ausmessung des HERTZschen Kegelbruchs gestattet nur begrenzt dynamische Messungen in zeitlich großen Abständen. Für die Ermittlung der interessierenden Parameter sind mehrere Blickrichtungen nötig. Das Ergebnis der einzelnen Messungen ist stark von subjektiven Fehlern beeinflußt. Eine Reproduzierbarkeit ist nicht gewährleistet (Schnapp, J. D.: Weiterentwicklung und Anwendung des Kugeleindruckverfahrens zur Untersuchung von Glasoberflächen. Dissertation B, Hochschule für Architektur und Bauwesen Weimar, Weimar 1983).The microscopic measurement of the HERTZ's cone fracture permits only limited dynamic Measurements at large intervals. For the determination of the parameters of interest require several viewing directions. The result of the individual measurements is strongly subjective Errors affected. Reproducibility is not guaranteed (Schnapp, J. D .: Further development and application of the ball indentation method for the investigation of Glass surfaces. Dissertation B, University of Architecture and Civil Engineering Weimar, Weimar 1983).
Das verwendete Bildverarbeitungssystem MeSys 2000 dient zur hochgenauen Ausmessung von Kleinteilen und Strukturen. Eine Anwendung bei Messungen an HERTZschen Kegelbrüchen erfolgte bisher nicht (Goldschmidt, R.; Schulz, H.: Modulares Meßsystem für optoelektronische Komponenten von Bildeinzugskanälen. Jenaer Rundschau 36 (1991) H. 3).The MeSys 2000 image processing system is used for high-precision measurement of small parts and structures. A Used for measurements on HERTZ cone breaks not yet (Goldschmidt, R .; Schulz, H .: Modular Measurement System for optoelectronic components of image acquisition channels. Jenaer Rundschau 36 (1991) H. 3).
Die Erfindung hat das Ziel, die Festigkeit und bruchmechanische Kennwerte von Gläsern sowie keramischen und glaskeramischen Werkstoffen auf Grundlage der Kugeleindruckmethode objektiviert zu ermitteln.The invention has the goal of strength and fracture mechanical Characteristic values of glasses as well as ceramic and glass-ceramic Materials objectified based on the ball indentation method to determine.
Die Lösung der Aufgabe ist dadurch gekennzeichnet, daß die Entstehung des HERTZschen Kegelbruchs mit einer CCD-Matrixkamera erfaßt und mit einem Bildverarbeitungssystem und entsprechenden Algorithmen ausgewertet wird.The solution to the problem is characterized in that the Formation of the HERTZ cone break with a CCD matrix camera captured and with an image processing system and corresponding Algorithms is evaluated.
Die Entstehung des HERTZschen Kegelbruchs als Maß für Festigkeit und bruchmechanische Kennwerte zum Beispiel in Glas läßt sich optisch aus einer Richtung erfassen, wobei Bilder in zeitlich definierten Abständen aufgenommen werden.The emergence of the HERTZ cone fracture as a measure of strength and fracture mechanical parameters, for example in glass optically capture from one direction, taking pictures in temporal defined intervals.
Das Verfahren wird anhand eines Ausführungsbeispieles erläutert. Es zeigenThe method is explained using an exemplary embodiment. Show it
Fig. 1 Darstellung des Prinzips der Kugeleindruckmethode, Fig. 1 illustrates the principle of the ball impression method,
Fig. 2 Messung der Geometrie des HERTZschen Kegelbruches, Fig. 2 Measurement of the geometry of the Hertzian cone fracture,
Fig. 3 Messung bei nichtsymmetrischem Rißwachstum, Fig. 3 measurement at non-symmetrical crack growth,
Fig. 4 Messung bei auftretenden Störgrößen. Fig. 4 measurement when disturbances occur.
In Fig. 1 sind die Größen des HERTZschen Kegelbruchs bei Anwendung der Kugeleindruckmethode dargestellt. Dabei ist F die einwirkende Kraft, ck die Rißlänge beim Kegelbruch, dHKB der Sprungkreisdurchmesser des HERTZschen Kegelbruchs, d'HKB der Basisdurchmesser des HERTZschen Kegelbruchs und f der Winkel zwischen HERTZschen Kegelbruch und Glasoberfläche. Für die Ausmessung der Parameter des HERTZschen Kegelbruch ist die Anordnung von mindesten drei Meßfenstern nötig. Diese müssen die als Hell-Dunkel- bzw. Dunkel-Hell-Übergänge erscheinenden Geraden des Sprungkreisdurchmessers (g1), der Rißlänge (g2) und des Basisdurchmessers (g3) sicher überdecken (Fig. 2). Bei einem nichtsymmetrischen Wachstum des HERTZschen Kegelbruchs ist eine Anordnung von fünf Meßfenstern notwendig, wobei zusätzlich die als Hell-Dunkel- bzw. Dunkel-Hell-Übergänge erscheinenden Geraden g4 und g5 überdeckt werden (Fig. 3). Die Definition der Geraden erfolgt durch Mittelung der an den Übergängen beteiligten Punkte.In Fig. 1, the sizes of the Hertzian cone collapse in use of the ball impression method are shown. F is the acting force, ck is the crack length at the cone break, dHKB is the jumping circle diameter of the HERTZ cone break, d'HKB is the base diameter of the HERTZ cone break and f is the angle between HERTZ's cone break and the glass surface. To measure the parameters of the HERTZ cone break, at least three measuring windows must be arranged. These must surely cover the straight lines of the jumping circle diameter (g 1 ), the crack length (g 2 ) and the base diameter (g 3 ), which appear as light-dark or dark-light transitions ( FIG. 2). In the case of a non-symmetrical growth of the HERTZ cone fracture, an arrangement of five measurement windows is necessary, the lines g 4 and g 5 appearing as light-dark or dark-light transitions also being covered ( FIG. 3). The straight line is defined by averaging the points involved in the transitions.
Die Schnittpunkte der so ermittelten Geraden ergeben die Eckpunkte des HERTZschen Kegelbruchs. Auf Grund der geometrischen Verhältnisse lassen sich aus diesen Punkten die Parameter des HERTZschen Kegelbruchs errechnen und bruchmechanische Kennwerte wie Rißenergie bestimmen. Treten im Bild des HERTZschen Kegelbruchs sichtbare Störungen an den Hell-Dunkel- bzw. Dunkel- Hell-Übergängen auf, so sind die Meßfenster so anzuordnen, daß die Störgrößen nicht überdeckt werden (Fig. 4). Durch die Anwendung des Bildverarbeitungssystems MeSys 2000 ist das Aufnehmen und Speichern von Bildern in kurzen Zeitabständen möglich. Erstens wird die Entstehung des HERTZschen Kegelbruchs bei kontinuierlich zunehmend gemessener Kraft registriert. Die Kraft bei der Herausbildung des Sprungkreises ist ein Maß für die Festigkeit des untersuchten Werkstoffes. Die Festigkeit läßt sich nach folgender Formel berechnen: δr=F(1-2v)/(2πr2). F ist dabei die einwirkende Kraft, r der Radius der Kugel die auf die Glasprobe drückt und v die Poisson-Konstante. Zweitens werden durch die zeitlich gestaffelte Aufnahme von Bildern des HERTZschen Kegelbruchs bei konstanter Krafteinwirkung oder bei kontinuierlich zunehmender Krafteinwirkung bruchmechanische Kennwerte bestimmt (z. B. Rißgeschwindigkeit, Rißenergie). Die Parameter des HERTZschen Kegelbruchs werden sowohl während der Aufnahme der Bilder als auch zu einem späteren Zeitpunkt an Hand von abgespeicherten Bildern, die sich entsprechenden Zeitpunkten und Kräften zuordnen lassen, bestimmt.The intersections of the straight lines determined in this way result in the corner points of the HERTZ cone fracture. On the basis of the geometric relationships, the parameters of the HERTZ cone fracture can be calculated from these points and fracture mechanical parameters such as crack energy can be determined. If there are visible disturbances at the light-dark or dark-light transitions in the image of the HERTZ cone fracture, the measuring windows must be arranged so that the disturbance variables are not covered ( Fig. 4). By using the MeSys 2000 image processing system, it is possible to record and save images at short intervals. First, the occurrence of the HERTZ cone fracture is registered with a continuously increasing force. The force in the formation of the spring circle is a measure of the strength of the investigated material. The strength can be calculated using the following formula: δr = F (1-2v) / (2πr 2 ). F is the acting force, r is the radius of the sphere pressing on the glass sample and v is the Poisson constant. Secondly, the staggered recording of images of the HERTZ cone fracture with constant force or with continuously increasing force determines fracture mechanical parameters (e.g. crack speed, crack energy). The parameters of the HERTZ cone fracture are determined both during the acquisition of the images and at a later point in time on the basis of stored images which can be assigned to appropriate times and forces.
Claims (8)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19914128233 DE4128233A1 (en) | 1991-08-26 | 1991-08-26 | Measuring strength of glass and ceramics - using image processing method having measuring windows |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19914128233 DE4128233A1 (en) | 1991-08-26 | 1991-08-26 | Measuring strength of glass and ceramics - using image processing method having measuring windows |
Publications (1)
Publication Number | Publication Date |
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DE4128233A1 true DE4128233A1 (en) | 1993-03-04 |
Family
ID=6439121
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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DE19914128233 Withdrawn DE4128233A1 (en) | 1991-08-26 | 1991-08-26 | Measuring strength of glass and ceramics - using image processing method having measuring windows |
Country Status (1)
Country | Link |
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DE (1) | DE4128233A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2001088502A2 (en) * | 2000-05-15 | 2001-11-22 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e. V. | Method and device for determining at least one mechanical fracturing material parameter |
-
1991
- 1991-08-26 DE DE19914128233 patent/DE4128233A1/en not_active Withdrawn
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2001088502A2 (en) * | 2000-05-15 | 2001-11-22 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e. V. | Method and device for determining at least one mechanical fracturing material parameter |
WO2001088502A3 (en) * | 2000-05-15 | 2002-05-23 | Fraunhofer Ges Forschung | Method and device for determining at least one mechanical fracturing material parameter |
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Legal Events
Date | Code | Title | Description |
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8139 | Disposal/non-payment of the annual fee |