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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Materials and structures 9 (1976), S. 83-89 
    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Summary It is necessary to consider the advantages and limitations of each of the numerous methods available today for the analysis of stress. Systematic studies are lacking on this subject. The author deals in a qualitative manner with the relative efficiency of the so-called finite element methods in respect with the experimental stress analysis methods. He also makes considerations on the relative merits of: 1) photoplasticity and moiré to solve problems in plasticity; 2) photo-ortho-elasticity, photoelastic coatings, and moiré to solve anisotropic problems; 3) several of the methods used today to solve problems in dynamic photoelasticity; 4) the methods used in three-dimensional photoelasticity, and in general about the photoelasticity methods, moiré, holography, brittle coatings, and the point-by-point methods. The analysis presented in the paper can be considered only preliminary. The author, however, gives reasons for his preference for the whole-field methods and for the diffused light polariscopes, for the use of moiré to solve problems in plasticity and in anisotropy, and for the use of the methods of repeated flashes to solve reproduceable problems in dynamic photoelasticity. He also shows that in general the “freezing” method is the most pratical and the most precise to solve three-dimensional problems. He thinks that the method of finite elements has replaced, or will soon replace, two-dimensional static photoelasticity. On the other hand, photoelasticity seems to be the most efficient method to solve dynamic problems, optimization problems, and three-dimensional problems.
    Notes: Résumé Il est nécessaire de considérer les avantages et les limitations des nombreuses méthodes dont on dispose aujourd'hui pour l'analyse des contraintes. Des études systématiques manquent sur cette question. L'auteur s'occupe qualitativement de l'efficacité relative des méthodes dites des éléments-finis par rapport aux méthodes expérimentales d'analyse des contraintes. Il fait quelques considérations aussi sur la valeur relative de: 1o la photoplasticité et le moiré pour résoudre des problèmes de plasticité; 2o la photo-ortho-élasticité, la couche photoélastique et le moiré pour résoudre des problèmes d'anisotropie; 3o plusieurs des méthodes employées maintenant pour résoudre des problèmes de photoélasticité dynamique; 4o les méthodes employées en photoélasticité tridimensionnelle, et en général sur les méthodes photoélastiques, du moiré, de l'holographie, des pellicules fragiles et des méthodes ponctuelles.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Die Arbeit beschäftigt sich mit der experimentellen Spannungsermittlung in einer Zylinderschale mit zwei gegenüberliegenden, randverstärkten Kreislöchern verschiedenen Durchmessers. Die Schale wird durch Innendruck beansprucht. Sowohl Reißlack als auch dreidimensionale photoelastische Methoden wurden zur Analyse verwendet. Die erhaltenen Resultate werden mit jenen für ein nicht randverstärktes Loch in einer glatten bzw. verrippten Zylinderschale verglichen.
    Notes: Summary This paper deals with an experimental determination of the stress distribution in a cylindrical shell with two diametrically opposite reinforced circular holes of different diameters. The shell is subjected to internal pressure. Both brittle coating and three-dimensional photoelasticity were used in the analysis. The results obtained are compared with those corresponding to a non-reinforced hole in a cylindrical shell with and without ribs.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Acta mechanica 24 (1976), S. 219-238 
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung In der Einfrier-Methode der dreidimensionalen Spannungsoptik werden Materialien mit einer Poisson-Zahl bei der kritischen Temperatur von 0.5 verwendet. Zwei bedeutende Einschränkungen folgen daraus: Die erhaltene Lösung gilt nur für Werkstoffe mit großer Poisson-Zahl, und es ist nicht möglich, die spannungsoptischen Messungen durch mechanische oder solche nach der Moiré-Methode zu ergänzen. In der neuen Technik wird ein Material mit einer Poisson-Zahl von ca. 0.4 verwendet. Da die Deformation groß ist (Größenordnung 1%) und das Material nicht inkompressibel ist, können mechanische Messungen oder die Moiré-Methode zur Ergänzung der spannungscptischen Messungen herangezogen werden. Falls erwünscht, können dreidimensionale Probleme nur mit mechanischen Messungen oder nach der Moiré-Methode gelöst werden. Am Beispiel einer Kugel unter diametraler Belastung wird die Anwendung der Methode und die Genauigkeit der Resultate illustriert.
    Notes: Summary The “freezing” method of three-dimensional photoelasticity uses materials which exhibit a Poisson's ratio equal to 0.5 at the critical temperature. Two important limitations follow: 1) the solution obtained applies only to materials with high Poisson's ratio. 2) to obtain principal stresses it is not possible to supplement birefringence measurements with mechanical or moire measurements. The new method uses a material with Poisson's ratio equal to about 0.4. Since the deformations are relatively large, (of the order of 1%) and the material is not incompressible, mechanical or moire measurements can be used to supplement birefringence measurements. If desired the method can be self sufficient and solve completely three-dimensional problems using only mechanical or moire measurements. A sphere subjected to diametral loading is used to illustrate the application of the method and the precision of the results obtained.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Acta mechanica 18 (1973), S. 305-315 
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Hauptziel der Arbeit ist die Angabe einer Methode, welche die experimentelle Bestimmung der Spannungen gestattet, die durch Schwingungen in verformbaren, in einer Flüssigkeit befindlichen Teilen unter Vorspannung auftreten. Anwendungsziel der Arbeit ist die Angabe einer Methode, welche zum Verständnis einer Form des Verhaltens Boje-Kabel unter der Wirkung von Wasserwellen beitragen kann. Die Spannungsoptik wird zur Untersuchung herangezogen. Als Kabelmodell wird ein Gummistab und als Modell der Boje ein runder Plastikbehälter verwendet. Wellen bestimmter Frequenz werden durch einen Schwingungserreger erzeugt. Die Spannungen im Stab werden bestimmt, und eine mögliche Übertragung der ermittelten Resultate auf Prototypen mit Hilfe von Ähnlichkeitsgesetzen wird vorgeschlagen.
    Notes: Summary A basic object of the paper is the presentation of a method that permits the experimental determination of stresses associated with vibrations in flexible members, immersed in a fluid, and subjected to prestress. The applied object of the paper is to present a method that may help in the visualization of one form of behavior of buoy-cable systems loaded by the action of water waves. Photoelasticity is used for the analysis. The cable is modeled by a solid urethane rubber strip and the buoy by a floating plastic round can. Waves of controllable frequency are produced by a device actuated by a shaker. Bending and axial stresses in the strip are determined and the possible extension of the experimental results obtained to prototypes by means of scaling laws is suggested.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Acta mechanica 3 (1967), S. 352-359 
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Bei einer Epoxy-Kunstharzplatte, die einseitig auf eine starre Unterlage geklebt wurde, entwickelte sich im Verlauf des Einfrierens des photoelastischen Effektes ein Zustand behinderter Schrumpfung. Dünne, von der Platte abgetrennte Scheiben wurden benutzt, um den Spannungszustand zu ermitteln.
    Notes: Summary A square epoxy slab was bonded to a rigid plate on one of its faces. In the process of “freezing” photoelastic effects a state of restrained shrinkage developed. Slices removed from the slab were used to determine the stress.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Experimental mechanics 1 (1961), S. 33-42 
    ISSN: 1741-2765
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract An experimental stress analysis of three cylindrical pressure vessels with radius/thickness ratios ranging from 100 to 238 and different head closures is described. Brittle coatings and electrical strain gages were employed to determine stress distributions over the entire outer surface of the vessels. Electrical strain gages alone were used to determine stresses on the inside surface of the vessels. Particular emphasis was placed on determining stress concentrations and on nonlinear effects produced by geometric imperfections. An attempt was also made to correlate the failure, which started in the cylindrical portion of the three vessels, with the elastic-stress distribution. It was found that the imperfections in the cylinder were not significant if the vessel was fabricated from a ductile steel. However, if the vessel was constructed from a high-strength but brittle steel, the imperfections significantly lower the bursting strength of the vessel.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Experimental mechanics 12 (1972), S. 496-501 
    ISSN: 1741-2765
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract It is shown in this paper how the whole field of displacement components and of their time and space derivatives (isothetics, isotachics and isoparagogics) can be obtained individually, as separate patterns in a simple and precise manner using spatial-filtering techniques. This result can be obtained even when crossed gratings are used on the deformed body. A method for achieving fringe multiplication in moiré patterns produced by superposed, crossed gratings is also demonstrated. It is also shown that displacement components and their time and space derivatives in directions diagonal to the crossed-grating lines can be obtained by proper handling of grating transparencies and spatial-filtering techniques. Hence, the moiré equivalent of a whole field of rosette-strain-gage measurements is obtained from a single photograph of a deformed crossed grating. A disk compressed between two wedges is used as an example. Important applications will be found in the fields of dynamics, nonlinear elasticity and plasticity.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Experimental mechanics 10 (1970), S. 497-505 
    ISSN: 1741-2765
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A particular variation of holographic imaging system is described which, when used as a multiple-exposure holographic interferometer, possesses advantages for applications in static and dynamic photomechanics. Large fields of view can be obtained. Rigid-body motions produced by loading are automatically eliminated. The holograms can be recorded on medium-resolution films which have high sensitivity. Specimens manufactured with readily available materials can be used for the determination of isochromatics and isopachics. An attempt is made to describe this contribution in the background of previous developments in interferometry. Operation of the system is interpreted by showing the equivalence of the holographic interferometer to a combination of two systems presently in use in experimental stress analysis: a Fizeau interferometer and an optical spatial filter. The interpretation of isochromatics and isopachis as moiré phenomena is emphasized. Isochromatics and isopachics are presented as illustrations of the applications of the method to the solution of static-stress problems, and they are used in the solution of some not yet solved dynamic-stress problems. Whole-field static isochromatics obtained as absolute-retardation interference are shown. Also shown are whole-field dynamic isopachics.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Experimental mechanics 10 (1970), S. 175-175 
    ISSN: 1741-2765
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Experimental mechanics 14 (1974), S. 206-206 
    ISSN: 1741-2765
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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