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Constrained cracking in glass fibre reinforced epoxy cross-ply laminates
Copper and nickel coated graphite particles can be successfully introduced into aluminium based alloy melts as pellets, to produce cast aluminium/ graphite particle composites. The optimum conditions for pressing the pellets are determined and the resultant properties of the alloy compared with those of material made by other production techniques.
Superconducting and mechanical properties of in situ formed multifilamentary Cu-Nb3 Sn composites Harbison, J.P. and Beuk, J. Journal of Applied Physics Vo148 No 12 pp 5180-5187 The superconducting transition temperature and critical current density are evaluated for a range of Cu-Nb 3 Sn composites fabricated by directional solidification followed by drawing. Critical current density is measured as a function of magnetic field and physical deformation. The composites are highly resistant to undesirable plastic flow on account of strong filament to Cu-matrix bonding and their close spacing, and develop high tensile strengths. Electronically and mechanically these discontinuous filament composites compare well with conventional continuous f'dament superconducting composites.
Superconducting properties of powder metallurgically produced Cu-Nb3 Sn composite wires Bormann, R., Schultz, L. and Freyhardt, H.C. Applied Physics Letters Vo132 No 1 (January 1978) pp 79-81 Composite wires containing discontinuous superconducting filaments in a normally conducting Cu-matrix have been produced by extrusion and subsequent drawing of compacted billets ofmetal powder. During an annealing treatment Nb3 Sn forms at the filament/matrix interface, and it is this precipitate which forms superconducting bridges between filaments. Critical current density is measured as a function of reduction in area, annealing temperature, tin concentration, and magnetic field. RESIN MA TRICES
Biaxial fatigue loading of notched
composites Francis, P.H., Walrath, D.E., Sims, D.F. and Weed, D.N. Journal Composite
286
Materials Vol 11 (October 1977) p 488 Thin walled graphite fibre/epoxy resin tubes of [0/90Is and [+ 45]s configurations, each with a small circular notch, were fatigued in combinations of axial, torsional and internal pressure laoding. S-N curves are presented for the various loading modes and a modified Hill anisotropic plane stress failure criterion found to agree well with experiment.
Carbon fibre in polymer reinforcement Donnet, P.J. and Ehrburger, P. Carbon Vol 15 (1977) pp 143-152 After introducing some of the established ideas on carbon fibre production from pan, and the resulting micro-structures, this review proceeds to discuss reinforcement of thermoplastics and thermosets with carbon fibres and various glass fibre types. The discussion develops around the role of the fibre surface and presents material properties for a range of fibres and surface treatments.
Constrained cracking in glass fibre reinforced epoxy cross-ply laminates Parvizi, A., Garrett, K.W. and Bailey, J.E. Journal of Materials Science Vol 13 No 1 (1978) pp 195-201 Specimens of 90 ° cross-ply glassreinforced epoxy resins, with varying inner-ply thickness, were tested in tension parallel to the direction of reinforcement in the outer plies. Cracking in the transverse ply is constrained for inner plies less than 0.4 mm thick and completely suppressed for inner plies less than 0.1 ram. Using fracture toughness values obtained from tests on transverse unidirectional laminates, the observed cracking constraint can be explained by the theory of Aveston and Kelly.
The correlation of ultrasonic attenuation and shear strength in graphite/polyimide composites Hay(oral, D.T., Henneke II, E.G. and Stinchcomb, W.W. Journal of Composite Materials Vo111 (October 1977) p 429 Failure loads of graphite/polyimide specimens tested in short beam shear are compared with ultrasonic attenuations recorded using a pulse/ echo technique and with ultrasonic C scan densities. Agreement between attenuation levels and applied loads is good, particularly at the high values of
attenuation. The data presented also correlates well with a qualitative assessment of the material integrity from ultrasonic C scans.
Determination of mechanical properties of frp composites through computer simulation Sarkar, K. and Murthy, P.N. Fibre Science and Technology 11ol11 No 2 (March 1978)pp 89-104 A method of numerical experimentation using computer simulation is described which has been used to determine the moduli of randomoriented, short fibre-reinforced composites. The process is simplified by using ribbon-type platelets in place of fibres. A tension model was also simulated and analysed. Close agreement was found in the results obtained and those from previous (Tsai-Pagano and Halpin-Tsai) relationships.
Edge effects in angle ply composite laminates Hsu, P.W. and Herakovich, C.T. Journal of Composite Materials Vol 11 (October 1977)pp 422-428 The results of a zeroth-order solution for edge effects in + 45 angle-ply graphite/epoxy laminates obtained using perturbation techniques and a limiting free body approach are presented as a function of the specimen thickness and an unknown problem parameter and compared with finite difference results. The solution predicts stable, continuous interlaminar stress distributions near the free edge as well as in the interior of the laminate.
Spherical inclusions reinforcement of plastics Wilczynski, A.P. Fibre Science and Technology Vo111 No 2 (March 1978) pp 105-111 Problems arising in the processing of fibre-reinforced thermoplastics can be largely overcome with the use of spherical reinforcement material. The paper considers some aspects of the theory of reinforcement using such spherically-shaped materials. Shrinkage stress in glass/resin
composites Harris, B. Journal of Materials Science Vol 13 (1978) pp 173-177 A simple shrink-fit model is used to calculate the interfacial pressures in a polyester-resin/glass fibre comp-
COMPOSITES . O C T O B E R 1978
Superconducting and mechanical properties of in situ formed multifilamentary Cu-Nb3 Sn composites Harbison, J.P. and Beuk, J. Journal of Applied Physics Vo148 No 12 pp 5180-5187 The superconducting transition temperature and critical current density are evaluated for a range of Cu-Nb 3 Sn composites fabricated by directional solidification followed by drawing. Critical current density is measured as a function of magnetic field and physical deformation. The composites are highly resistant to undesirable plastic flow on account of strong filament to Cu-matrix bonding and their close spacing, and develop high tensile strengths. Electronically and mechanically these discontinuous filament composites compare well with conventional continuous f'dament superconducting composites.
Superconducting properties of powder metallurgically produced Cu-Nb3 Sn composite wires Bormann, R., Schultz, L. and Freyhardt, H.C. Applied Physics Letters Vo132 No 1 (January 1978) pp 79-81 Composite wires containing discontinuous superconducting filaments in a normally conducting Cu-matrix have been produced by extrusion and subsequent drawing of compacted billets ofmetal powder. During an annealing treatment Nb3 Sn forms at the filament/matrix interface, and it is this precipitate which forms superconducting bridges between filaments. Critical current density is measured as a function of reduction in area, annealing temperature, tin concentration, and magnetic field. RESIN MA TRICES
Biaxial fatigue loading of notched
composites Francis, P.H., Walrath, D.E., Sims, D.F. and Weed, D.N. Journal Composite
286
Materials Vol 11 (October 1977) p 488 Thin walled graphite fibre/epoxy resin tubes of [0/90Is and [+ 45]s configurations, each with a small circular notch, were fatigued in combinations of axial, torsional and internal pressure laoding. S-N curves are presented for the various loading modes and a modified Hill anisotropic plane stress failure criterion found to agree well with experiment.
Carbon fibre in polymer reinforcement Donnet, P.J. and Ehrburger, P. Carbon Vol 15 (1977) pp 143-152 After introducing some of the established ideas on carbon fibre production from pan, and the resulting micro-structures, this review proceeds to discuss reinforcement of thermoplastics and thermosets with carbon fibres and various glass fibre types. The discussion develops around the role of the fibre surface and presents material properties for a range of fibres and surface treatments.
Constrained cracking in glass fibre reinforced epoxy cross-ply laminates Parvizi, A., Garrett, K.W. and Bailey, J.E. Journal of Materials Science Vol 13 No 1 (1978) pp 195-201 Specimens of 90 ° cross-ply glassreinforced epoxy resins, with varying inner-ply thickness, were tested in tension parallel to the direction of reinforcement in the outer plies. Cracking in the transverse ply is constrained for inner plies less than 0.4 mm thick and completely suppressed for inner plies less than 0.1 ram. Using fracture toughness values obtained from tests on transverse unidirectional laminates, the observed cracking constraint can be explained by the theory of Aveston and Kelly.
The correlation of ultrasonic attenuation and shear strength in graphite/polyimide composites Hay(oral, D.T., Henneke II, E.G. and Stinchcomb, W.W. Journal of Composite Materials Vo111 (October 1977) p 429 Failure loads of graphite/polyimide specimens tested in short beam shear are compared with ultrasonic attenuations recorded using a pulse/ echo technique and with ultrasonic C scan densities. Agreement between attenuation levels and applied loads is good, particularly at the high values of
attenuation. The data presented also correlates well with a qualitative assessment of the material integrity from ultrasonic C scans.
Determination of mechanical properties of frp composites through computer simulation Sarkar, K. and Murthy, P.N. Fibre Science and Technology 11ol11 No 2 (March 1978)pp 89-104 A method of numerical experimentation using computer simulation is described which has been used to determine the moduli of randomoriented, short fibre-reinforced composites. The process is simplified by using ribbon-type platelets in place of fibres. A tension model was also simulated and analysed. Close agreement was found in the results obtained and those from previous (Tsai-Pagano and Halpin-Tsai) relationships.
Edge effects in angle ply composite laminates Hsu, P.W. and Herakovich, C.T. Journal of Composite Materials Vol 11 (October 1977)pp 422-428 The results of a zeroth-order solution for edge effects in + 45 angle-ply graphite/epoxy laminates obtained using perturbation techniques and a limiting free body approach are presented as a function of the specimen thickness and an unknown problem parameter and compared with finite difference results. The solution predicts stable, continuous interlaminar stress distributions near the free edge as well as in the interior of the laminate.
Spherical inclusions reinforcement of plastics Wilczynski, A.P. Fibre Science and Technology Vo111 No 2 (March 1978) pp 105-111 Problems arising in the processing of fibre-reinforced thermoplastics can be largely overcome with the use of spherical reinforcement material. The paper considers some aspects of the theory of reinforcement using such spherically-shaped materials. Shrinkage stress in glass/resin
composites Harris, B. Journal of Materials Science Vol 13 (1978) pp 173-177 A simple shrink-fit model is used to calculate the interfacial pressures in a polyester-resin/glass fibre comp-
COMPOSITES . O C T O B E R 1978