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Plastic analysis of fibre interactions in discontinuous fibre composites
Abstracts of journals Compiled by H.A. Barker, I. Bell, B. Gill and T. Feest.
GENERAL Bending of laterally loaded, simply supported, moderately thick, antisymmetrically laminated rectangular plates Turvy, G.J. Fibre Science and Technology Vo110 No 3 (July 1977) pp 211-232 Exact and approximate analyses are presented for the flexural response including transverse shear deformations - of the rectangular plates subject to a variety of lateral load distributions. The results indicate that the approximate analysis is very accurate for cross-ply lay-ups, but less so for angle-ply lay-ups. The exact analysis, incorporating shear correction factors, is then used to provide detailed results for four different load cases. These results, it is suggested, may be useful to the designer and serve to illustrate which parameters affect the response of the plate.
Cryogenic mechanical properties of boron-, graphite and glass-reinforced composites Schramm, R.E. and Kasen, M.B. Materials Science and Engineering Vol 30 No 3 (November 1977) pp 197-204 The paper presents static tensile, compressive and shear properties for uniaxial laminates of boron/epoxy, boron/aluminium, graphite/epoxy and glass/epoxy composites at temperatures of 295, 76 and 4 K. The data also include tensile properties of-+ 45 ° cross-ply lay-ups and uniaxial thermal expansion. It is concluded that the composites studied display good static behaviour at cryogenic temperatures.
Eutectic solidification Elliott, R. lnternationalMetals Reviews Vo122 (September 1977) pp 161-186 The author attempts to show how recent solidification studies provide an understanding of the wide variety of eutectic microstructures. Modifications to early concepts of eutectic solidication have been made, enabling the rationalization of both eutectic solidication
COMPOSITES . APRIL
1978
behaviour in terms of the growth characteristics of the individual phases and the influence of solidication conditions on this behaviour. A quantitative comprehension of the solidification of normal structures of lamellar or rod type - which are finding increasing application as in situ composite materials - is demonstrated. The understanding of the solidification of the anomolous structures, found in the majority of commercial casting alloys, remains qualitative, however.
Fibre intersections in a planar randomly oriented fibre composite Williams, J.H., Jr, Lee, S.S. and Wasserman, C.S. Fibre Science and Technology Vol I0 No 3 (July 1977) pp 161-177 The authors present a theoretical model for the prediction of values of the mean and the variance of fibre intersections in a planar randomly oriented fibre composite; such intersections are considered to be a key factor in the determination of mechanical properties of the composites. The predictions obtained from the theoretical model are compared with the mean and variance obtained from a computer simulation of the fibre interaction process.
Heterogeneous anisotropic model for notched fibre composites Kousiounelos, P.N. and Williams, J.H. Jr Fibre Science and Technology Vo110 No 5 (October 1977) pp 299-311 A model is developed which takes into account the inhomogeneity of unidirectional fibre composites; and the singular crack-tip stress and strain fields for each constituent are obtained. The model is based on the assumption that the near crack-tip strain in the fibre reinforcement direction is the same at any point in both an equivalent homogeneous anisotropic body and the heterogeneous anisotropic composite. The model is applied to a graphite fibre/potysulphone fibre coating/epoxy matrix composite for a range of fibre-reinforcement angles, and the fibre and matrix stress fields
are plotted for a number of fibrereinforcement angles.
Plastic analysis of fibre interactions in discontinuous fibre composites Agarwal, B.D. and Bansal, R.K. Fibre Science and Technology Vo110 No 4 (October 1977) pp 281-297 Fibre interactions were studied using a single fibre model by suitable selection of boundary conditions. An elastic/plastic finite element analysis was carried out to establish the influence of fibre interaction on the load transfer mechanism, failure at the fibre/matrix interface, and the stress/ strain behaviour of a composite. A critical interaction fibre length is defined which, it is proposed, is necessary for effective reinforcement in a discontinuous fibre-reinforced composite.
Ply stacking sequences for laminated plates having in-plane and bending orthotropy Bartholomew, P. Fibre Science and Technology Vo110 No 4 (October 1977) pp 239-253 It is demonstrated that orthotropy in bending, as well as in-plane, can be achieved for uncoupled, orthotropic laminates by selection of a suitable ply stacking order. A class of'aminate is described which lacks ply symmetry about the mid-plane but which exhibits bending and in-plane orthotropy; and which has no elastic coupling between in-plane and bending effects.
A review of advanced materials for MX booster nozzles - Part 1 Kotlensky, W.V. et al SAMPE Quarterly Vol 8 No 3 (April 1977) pp 1-9 Graphitic materials, being developed and evaluated in the USA for use as solid rocket nozzles, are discussed. The materials under investigation were carbon/carbon composites, pyrolytic graphite and carbon/phenolic composites. Projections are made of future trends expected in nozzle design and the development of graphitic materials, as well as anticipated improvements in materials performance.
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GENERAL Bending of laterally loaded, simply supported, moderately thick, antisymmetrically laminated rectangular plates Turvy, G.J. Fibre Science and Technology Vo110 No 3 (July 1977) pp 211-232 Exact and approximate analyses are presented for the flexural response including transverse shear deformations - of the rectangular plates subject to a variety of lateral load distributions. The results indicate that the approximate analysis is very accurate for cross-ply lay-ups, but less so for angle-ply lay-ups. The exact analysis, incorporating shear correction factors, is then used to provide detailed results for four different load cases. These results, it is suggested, may be useful to the designer and serve to illustrate which parameters affect the response of the plate.
Cryogenic mechanical properties of boron-, graphite and glass-reinforced composites Schramm, R.E. and Kasen, M.B. Materials Science and Engineering Vol 30 No 3 (November 1977) pp 197-204 The paper presents static tensile, compressive and shear properties for uniaxial laminates of boron/epoxy, boron/aluminium, graphite/epoxy and glass/epoxy composites at temperatures of 295, 76 and 4 K. The data also include tensile properties of-+ 45 ° cross-ply lay-ups and uniaxial thermal expansion. It is concluded that the composites studied display good static behaviour at cryogenic temperatures.
Eutectic solidification Elliott, R. lnternationalMetals Reviews Vo122 (September 1977) pp 161-186 The author attempts to show how recent solidification studies provide an understanding of the wide variety of eutectic microstructures. Modifications to early concepts of eutectic solidication have been made, enabling the rationalization of both eutectic solidication
COMPOSITES . APRIL
1978
behaviour in terms of the growth characteristics of the individual phases and the influence of solidication conditions on this behaviour. A quantitative comprehension of the solidification of normal structures of lamellar or rod type - which are finding increasing application as in situ composite materials - is demonstrated. The understanding of the solidification of the anomolous structures, found in the majority of commercial casting alloys, remains qualitative, however.
Fibre intersections in a planar randomly oriented fibre composite Williams, J.H., Jr, Lee, S.S. and Wasserman, C.S. Fibre Science and Technology Vol I0 No 3 (July 1977) pp 161-177 The authors present a theoretical model for the prediction of values of the mean and the variance of fibre intersections in a planar randomly oriented fibre composite; such intersections are considered to be a key factor in the determination of mechanical properties of the composites. The predictions obtained from the theoretical model are compared with the mean and variance obtained from a computer simulation of the fibre interaction process.
Heterogeneous anisotropic model for notched fibre composites Kousiounelos, P.N. and Williams, J.H. Jr Fibre Science and Technology Vo110 No 5 (October 1977) pp 299-311 A model is developed which takes into account the inhomogeneity of unidirectional fibre composites; and the singular crack-tip stress and strain fields for each constituent are obtained. The model is based on the assumption that the near crack-tip strain in the fibre reinforcement direction is the same at any point in both an equivalent homogeneous anisotropic body and the heterogeneous anisotropic composite. The model is applied to a graphite fibre/potysulphone fibre coating/epoxy matrix composite for a range of fibre-reinforcement angles, and the fibre and matrix stress fields
are plotted for a number of fibrereinforcement angles.
Plastic analysis of fibre interactions in discontinuous fibre composites Agarwal, B.D. and Bansal, R.K. Fibre Science and Technology Vo110 No 4 (October 1977) pp 281-297 Fibre interactions were studied using a single fibre model by suitable selection of boundary conditions. An elastic/plastic finite element analysis was carried out to establish the influence of fibre interaction on the load transfer mechanism, failure at the fibre/matrix interface, and the stress/ strain behaviour of a composite. A critical interaction fibre length is defined which, it is proposed, is necessary for effective reinforcement in a discontinuous fibre-reinforced composite.
Ply stacking sequences for laminated plates having in-plane and bending orthotropy Bartholomew, P. Fibre Science and Technology Vo110 No 4 (October 1977) pp 239-253 It is demonstrated that orthotropy in bending, as well as in-plane, can be achieved for uncoupled, orthotropic laminates by selection of a suitable ply stacking order. A class of'aminate is described which lacks ply symmetry about the mid-plane but which exhibits bending and in-plane orthotropy; and which has no elastic coupling between in-plane and bending effects.
A review of advanced materials for MX booster nozzles - Part 1 Kotlensky, W.V. et al SAMPE Quarterly Vol 8 No 3 (April 1977) pp 1-9 Graphitic materials, being developed and evaluated in the USA for use as solid rocket nozzles, are discussed. The materials under investigation were carbon/carbon composites, pyrolytic graphite and carbon/phenolic composites. Projections are made of future trends expected in nozzle design and the development of graphitic materials, as well as anticipated improvements in materials performance.
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