| 1. |
- Govada, Anil K., et al.
(författare)
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Acusto-ultrasonic measurements to minitor damage during fatigue of composistes
- 1984
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Ingår i: 1984 advances in aerospace sciences and engineering. - New York : American Society of Mechanical Engineers. ; , s. 55-60
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Konferensbidrag (refereegranskat)abstract
- An acousto-ultrasonic technique was used to monitor damage initiation and development in (0, 90//2)//s, (0, plus or minus 45)//s, and (0, 90, plus or minus 45)//s graphite epoxy laminates. The laminates were either loaded in quasi-static tension or were fatigued with tension-tension loading cycles. At a number of intermediate stages (strain levels for quasi-static tests and load cycles for the fatigue tests), the loading was halted and the acousto-ultrasonic measurements were made on the specimens. Several quantitative parameters, which include moments and ratios of moments of the frequency spectrum, were found to correlate extremely well with the stiffness change and the stress-strain behavior of the specimens.
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| 2. |
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| 3. |
- Talreja, Ramesh
(författare)
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Conceptual framework for the interpretation of fatique damage mechanisms in composite materials
- 1985
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Ingår i: Journal of composites technology & research. - 0884-6804 .- 1945-7537. ; 7:1, s. 25-29
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Tidskriftsartikel (refereegranskat)abstract
- This paper reviewed fatigue damage mechanisms in composite materials, giving an account of the historical developments. The present understanding has resulted from a large number of investigations, some of which have required developing new techniques and modifying earlier techniques for observing the complex damage process. The development of damage involves a sequence of mechanisms that may not be separable into distinct damage modes but rather into dominant damage modes
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| 4. |
- Talreja, Ramesh
(författare)
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Continuum mechanics characterization of damage in composite materials
- 1985
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Ingår i: Proceedings of The Royal Society of London. Series A, Mathematical and physical sciences. - : The Royal Society. - 0080-4630. ; 399:1817, s. 195-216
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Tidskriftsartikel (refereegranskat)abstract
- The mechanical response of a composite material damaged in fatigue, or in any other loading mode, is characterized by a set of vector fields, each representing a damage mode. Constitutive equations are derived for isothermal small-deformation behavior following attainment of a damage state. For small damage, the elastic constants of a damage state are related to those of the undamaged state. The usefulness of these relations in characterizing the development of damage, for instance during fatigue, is discussed
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| 5. |
- Talreja, Ramesh
(författare)
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Damage development in composites : mechanisms and modelling
- 1989
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Ingår i: Journal of Strain Analysis for Engineering Design. - 0309-3247 .- 2041-3130. ; 24:4, s. 215-222
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents first a review of the mechanisms of damage and its development in composite materials subjected to mechanical loads. The materials considered are thermosetting polymers reinforced with short or long fibers of glass or carbon. Laminates with woven fabric are also considered. A discussion regarding how the essential features of the damage mechanisms may be incorporated in a modelling approach is then given. Two basically different but complementary approaches, namely, micromechanics modelling and continuum damage modelling, are described. The author's own approach using the internal variables concept is discussed at some length, and the predictions of elastic property degradation given by it are illustrated by experimental data.
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| 6. |
- Talreja, Ramesh
(författare)
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Damage mechanics analysis of interlaminar cracking in composites
- 1989
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Ingår i: Mechanical and corrosion properties : Series A, Key engineering materials. - 0252-1059. ; 37, s. 21-34
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Tidskriftsartikel (refereegranskat)abstract
- Interlaminar fracture in composite laminates may initiate either from a free edge, where a triaxial state of stress exists, or from an interior region, where intralaminar cracks may divert into the interlaminar layers. Experimental evidence has shown that while the free edge related interlaminar cracking is localized, the interior delamination may be distributed in a wider region. The individual cracks associated with the interior delamination are generally small, at least initially, in comparison to the structural dimensions. This paper treats the interior delamination using a damage mechanics approach where the damage is represented by internal state variables. A tensorial description of damage is adopted which leads to a single parameter characterization of the interlaminar cracking. A phenomenological theory of stress-strain response is then developed and relationship between the overall moduli and the severity of interlaminar cracking are derived.
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| 7. |
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| 8. |
- Talreja, Ramesh
(författare)
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Fatigue of composite materials : damage mechanisms and fatigue-life diagrams
- 1981
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Ingår i: Proceedings of The Royal Society of London. Series A, Mathematical and physical sciences. - : The Royal Society. - 0080-4630. ; 378:1775, s. 461-475
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Tidskriftsartikel (refereegranskat)abstract
- The basic fatigue damage mechanisms in composite laminates are reviewed. Based on these mechanisms a pattern in the fatigue-life diagrams is proposed. Several experimental data are shown to agree with this basic pattern. Fatigue ratio is defined in terms of strains, and fatigue limit is shown to exist for unidirectional, cross-plied and angle-plied laminates. The limitations to the fatigue performance of composite laminates are pointed out and suggestions for improving the fatigue resistance are made
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| 9. |
- Talreja, Ramesh
(författare)
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Fatigue reliability under random loads
- 1983
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Ingår i: Reliability Engineering & System Safety. - 0951-8320 .- 1879-0836. ; 5:2, s. 87-90
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Tidskriftsartikel (refereegranskat)
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| 10. |
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