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Predicting mold flow for unsaturated polyester resin sheet molding compounds
Review Vol 2 No 3 (1980) pp 9-11 Work is reported on an assessment of the degree of isotropy exhibited by certain quasi-isotropic sandwich construction materials (graphite/polyimide skin with glass-reinforced polyimide core). T h e use of S t a n d a r d i s o t r o p i c strength-of-materials formulae were found to be applicable for predicting the response of these quasi-isotropic components for certain loadings. Numerical data are presented for the sandwich material considered. Mechanics of intraply composites - properties, analysis and design Chamis, C.C. and Sinclair, J.H. Polymer Composites Vol 1 No 1 (September 1980) pp 7-13 A mechanics theory has been developed for predicting the physical, thermal, hygral and mechanical properties of unidirectional intraply hybrid composites, based on the unidirectional properties of the constituent materials. Also described in the paper are procedures which enable the use of the theory in conjunction with composite mechanics computer codes and general purpose structural analysis finite element programs for the analysis and design of structural components using intraply hybrid angle-plied laminates. The mechanism of failure in bending of paperboard Carlsson, Leif., Fellers, Christer. and Ruvo, Aif de. Journal o f Materials Science Vol 15 pp 2636-2642 The behaviour of paperboard beams subjected to pure bending is analysed and related to tensile and compression stress-strain behaviour. Beam failure occurs in compression, since the compressive strength is lower than the tensile. Beam failure does not occur when the ultimate strain in pure compression is reached in the surface fibres, a plastic yielding in compression is suggested to occur.
Melt crystallization of polypropylene: effect of contact with fibre substrates Campbell, D., and Qayyum, M.M. Jounrla of Polymer Science Poly. Phys. Ed Vol 18 (1980) p 83093 The isothermal crystallization of isotactic polyporopylene at different temperatures in the presence of fibrous substrates has been investigated. It is shown that preferential transcrystalline growth occurs at the fibre surface and that changes in nucleation density in the bulk material adjacent to the fibres also occur, the extent of which depends on temperature and fibre VF.
COMPOSITES. APR I L 1981
Mica composites of improved strength Newman, S. and Meyer, F.J. Polymer Composites Vol 1 No 1 (September 1980) pp 37-43 Mica-reinforced polypropylene composites have been studied, particular aspects of the investigation being: identification of specific non-silane additives to modify the mica/polypropylene interface; demonstration of the effects of time/temperature during melt processing on the behaviour of the material; and indicating the relationship between composition and time/temperature effects on the mechanical, physical and thermal properties of the composite. Micromechanisms controlling fracture toughness of brittle composites Buresch, F.E. Powder Metallurgy International Vol 12 No 3 (August 1980) pp 123-127 The good thermo-mechanical properties of A1203 ceramics containing a dispersion of unstabilized Zr02 particles can be attributed to a high density of micro-cracks. A theory is developed for the interaction of these microcracks with the process zone at a brittle crack tip, and it is shown to agree with fracture toughness measurements. Moisture absorption of polyester/Eglass composites Loos, A.C., Springer, G.S., Sanders, B.A. and Tung, R.W. Journal of Composite Materials Vol 14 (April 1980) p 142 Moisture absorption of polyester/Eglass composites immersed in distilled water, salt water, Nu. 2 diesel fuel, jet A fuel, synthetic aviation lubricant, gasoline and a humid environment were measured by weight change. The apparant maximum moisture contents and the apparent diffusivities were deduced from the data. Predicting mold flow for unsaturated polyester resin sheet molding compounds Silva-Nieto, R.J., Fisher, B.C. and Birley, A.W. Polymer Composites Vol 1 No 1 (September 1980)pp 14-23 Theoretical and experimental work is described which has developed a charge shape calculation procedure for moulding two-dimensional SMC components that are weld-line free without substantially altering the SMC matrix/glass fibre orientation. Proof test and fatigue of unnotched composite laminates
Yang, J.N. and Sun, C.T. Journal of Composite Materials Vol 14 (April 1980) p 168 A comprehensive fatigue and residual strength degradation model has been used to predict the effect of proof loads on the statistical fatigue behaviour of composite laminates. Correlation between graphite/epoxy results and the theoretical distributions of fatigue life and residual strength, with or without proof loading, is good.
Pvc/Cu composites with chemically deposited ultraflne copper particles Das, D., Basu, S., and Paul, A. Journal o f Materials Science Vol 15 (1980) pp 1719-1723 Pvc/Cu composites were hot pressed from 150 # m pvc powder coated with 0.1 - - 0.3/am copper particles. As little as 0.5 volume % of Cu imparted electrical conductivity through the formation of a segregated electrically conducting network. The small amount of metal required was a consequence of the large ratio of particle sizes. An addition of 4.0 volume % Cu increased the rupture strength by 200%. Review: The effect of particle shape on the mechanical properties of filled polymers Chow, T.S. Journal of Materials Science Vol 15 (1980) pp 1873-1888 The review seeks a unified approach to the effect of particle shape in the elastic moduli, thermal expansion, stress concentration factor, and viscoelastic response of filled polymers. The interrelationship between these properties is discussed, as is the effect of anisotropic p a r t i c l e s h a p e on m e c h a n i c a l behaviour. Simplified formulas for elastic moduU of unidirectional continuous f b r e composites Hahn, H.T. Composites Technology Review Vol 2 No 3 (1980) pp 5-7 Previously-derived equations for assessing composite behaviour in terms of fibre and matrix properties are simplified, for use with unidirectionally reinforced composites. This simplification enables easy modification to obtain better experimental correlation. Some observations on the production of polyethylene fibres by the surface growth method Barham, P.J. and Keller, A. Journal of Materials Science Vol 15 pp 22292235 Results of a study of the parameters
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Melt crystallization of polypropylene: effect of contact with fibre substrates Campbell, D., and Qayyum, M.M. Jounrla of Polymer Science Poly. Phys. Ed Vol 18 (1980) p 83093 The isothermal crystallization of isotactic polyporopylene at different temperatures in the presence of fibrous substrates has been investigated. It is shown that preferential transcrystalline growth occurs at the fibre surface and that changes in nucleation density in the bulk material adjacent to the fibres also occur, the extent of which depends on temperature and fibre VF.
COMPOSITES. APR I L 1981
Mica composites of improved strength Newman, S. and Meyer, F.J. Polymer Composites Vol 1 No 1 (September 1980) pp 37-43 Mica-reinforced polypropylene composites have been studied, particular aspects of the investigation being: identification of specific non-silane additives to modify the mica/polypropylene interface; demonstration of the effects of time/temperature during melt processing on the behaviour of the material; and indicating the relationship between composition and time/temperature effects on the mechanical, physical and thermal properties of the composite. Micromechanisms controlling fracture toughness of brittle composites Buresch, F.E. Powder Metallurgy International Vol 12 No 3 (August 1980) pp 123-127 The good thermo-mechanical properties of A1203 ceramics containing a dispersion of unstabilized Zr02 particles can be attributed to a high density of micro-cracks. A theory is developed for the interaction of these microcracks with the process zone at a brittle crack tip, and it is shown to agree with fracture toughness measurements. Moisture absorption of polyester/Eglass composites Loos, A.C., Springer, G.S., Sanders, B.A. and Tung, R.W. Journal of Composite Materials Vol 14 (April 1980) p 142 Moisture absorption of polyester/Eglass composites immersed in distilled water, salt water, Nu. 2 diesel fuel, jet A fuel, synthetic aviation lubricant, gasoline and a humid environment were measured by weight change. The apparant maximum moisture contents and the apparent diffusivities were deduced from the data. Predicting mold flow for unsaturated polyester resin sheet molding compounds Silva-Nieto, R.J., Fisher, B.C. and Birley, A.W. Polymer Composites Vol 1 No 1 (September 1980)pp 14-23 Theoretical and experimental work is described which has developed a charge shape calculation procedure for moulding two-dimensional SMC components that are weld-line free without substantially altering the SMC matrix/glass fibre orientation. Proof test and fatigue of unnotched composite laminates
Yang, J.N. and Sun, C.T. Journal of Composite Materials Vol 14 (April 1980) p 168 A comprehensive fatigue and residual strength degradation model has been used to predict the effect of proof loads on the statistical fatigue behaviour of composite laminates. Correlation between graphite/epoxy results and the theoretical distributions of fatigue life and residual strength, with or without proof loading, is good.
Pvc/Cu composites with chemically deposited ultraflne copper particles Das, D., Basu, S., and Paul, A. Journal o f Materials Science Vol 15 (1980) pp 1719-1723 Pvc/Cu composites were hot pressed from 150 # m pvc powder coated with 0.1 - - 0.3/am copper particles. As little as 0.5 volume % of Cu imparted electrical conductivity through the formation of a segregated electrically conducting network. The small amount of metal required was a consequence of the large ratio of particle sizes. An addition of 4.0 volume % Cu increased the rupture strength by 200%. Review: The effect of particle shape on the mechanical properties of filled polymers Chow, T.S. Journal of Materials Science Vol 15 (1980) pp 1873-1888 The review seeks a unified approach to the effect of particle shape in the elastic moduli, thermal expansion, stress concentration factor, and viscoelastic response of filled polymers. The interrelationship between these properties is discussed, as is the effect of anisotropic p a r t i c l e s h a p e on m e c h a n i c a l behaviour. Simplified formulas for elastic moduU of unidirectional continuous f b r e composites Hahn, H.T. Composites Technology Review Vol 2 No 3 (1980) pp 5-7 Previously-derived equations for assessing composite behaviour in terms of fibre and matrix properties are simplified, for use with unidirectionally reinforced composites. This simplification enables easy modification to obtain better experimental correlation. Some observations on the production of polyethylene fibres by the surface growth method Barham, P.J. and Keller, A. Journal of Materials Science Vol 15 pp 22292235 Results of a study of the parameters
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