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Making the most of carbon fibre
used in composites at temperatures of up to 1000°C in air. T h e advantages that might be realized from other fibres if oxidation were to be prevented are readily seen from the graphs. (71 / 1/94) Making the most of carbon fibre
Mortimer, J. The Engineer, p 26 (24
June 1971) T h e types of carbon fibre and resin available are examined and the methods of using them in current engineering practice are discussed. T h e roles of carbon fibres in shafting and blading in general and in the development of the RB211 in particular are discussed. (71/1/95) The mechanical performance of cromplied composites
Lavengood,
R.
E.
and
Ishai,
O.
Polymer Engineering and Scie~nce, Vol 11, No 3, p 226 (May 1971) T h e tensile behaviour of glass-fibre/ epoxy cross-plied laminates was investigated for both brittle and ductile matrices and it was found that in both types of of system the laminae showed higher strength, stiffness and toughness than equivalent unidirectional composites. In the case o f 90°-0 ° systems the use of a ductile matrix resulted in a marked increase in strength with only a slight decrease in stiffness with the initial cracking stress nearly doubled. This could mean that a t virtually no extra cost the usable strength would be doubled for some applications. (71/1 ]96) Mechanical properties of stressgraphitized carbon libers: thermally induced relaxation and recovery
Shrian, S. and Strong, S. L. Fibre
Science and Technology, Vol 4, No 1, p 67 (July 1971) High modulus carbon fibres produced from a rayon precursor by stretching at high temperatures showed changes i n dimensions and properties when heated above 700°(3 without an externally applied stress. Low temperature annealing was found to induce structural changes by reason of a relaxation in the graphite layer planes with an accompanying reduction in mechanical property values. Stress-graphitized fibres subjected to further h e a t i n g above 2400°C were found to undergo further graphitization and to become stabilized. (71/1/97)
Plasticity and initiation of fracture in crystals with non-deforming inclusions
Tanaka, K., Mori, T. and Nakamura,
T. Proceedings, 14th Japan Congress on Materials Research, Kyoto, pp 52-56 (1971) Non-deforming inclusions such as particles or fibres of a strong material can be used to reinforce metals. From theoretical considerations of the elastic state and thermodynamic stability of such composites expressions are derived for the work hardening behaviour and fracture initiation of the material. (71 / 1/ 99)
Pultrusion - - a growing topnage market for reinforced plastics end products
Brandt Galsworthy, W. Reinforced Plastics, Vol 15, No 6, p 134 (June 1971) T h e progress of pultrusion is traced and the technical aspects of radio frequency curing are examined in view of its influence on the development of the process. It is concluded that the process will he a strong contender in the market for structural rofiles principally because the very igh pressures needed to form large cross sections in traditional materials such as metals are not required in pultrusion. (71/1 / 100)
~
A new method is proposed for testing FRP. This involves simultaneous recording of sonic vibrations at various selected points and measurement of strain by suitably situated strain gauges. T h e test sample in this case was a closed cylinder filled with water under pressure. A theory is developed to predict its behaviour and a number of experiments have been carried out. Both 'sona-graph' and 'voice-print' type recordings have been made. More work is needed but wide future applications are foreseen. (71/1/103) A tension test for filamentary composites
Hancock, J. R. and Swanson, G. D.
Journal o] Composite Materials, Vol 5, pp 414-416 (July 1971) A description of a tensile test using a simple specimen rectangular crosssection. This test achieves accurate specimen alignment and failure in the gauge-length providing a valid test with economically small specimens. (71/1/104)
Mool,
D.
and
Stephenson,
R.
Materials Evaluation, Vol 29, No 7, pp 159-164 (July 1971)
Thorue, D.
T h e ability o f through-transmitted ultrasound to detect defects in a 10ply unidirectional b o r o n / e p o x y laminate bonded to aluminium face sheets was tested. Ultrasonic C-scans showed such defects. A variety of different faults w o u l d be detected and the technique is apparently an effective inspection method for this particular composite. (71/1 / 105)
J. and Price, A. J. Fibre Science and Technology, Vol 4, No 1, p 9 (July 1971) T w o types of carbon fibre were prepared from commercial acrylic fibre by oxidation in air and inert atmosphere pyrolysis at 1273 K in one case and in the other by the use of an additional treatment at 2773 K. Measurements of the reactivity of these fibres to oxidation by carbon dioxide were made by weight loss and showed that whilst the activation energies for the reaction was the same in both cases the fibres pyrolysed at 1273 K were approximately seven times as reactive as those subsequently heat treated at 2773 K. General surface smooth, ing and the development of an extensive micro-pore system was noted. (71/1 / 101)
Hagemaier, D. J., McFaul, H. J. and Moon, D. Materials Evaluation, Vol
Cline, H. E. Acta MetaUurgica, Vol
29, No 6, pp 133-140 (]u~e 1971)
In order to predict the stability and coarsening mechanisms in eutectic alloys, the growth of shape instabilities in a rod composite is calculated assuming that interface migration is driven by capillarity and controlled by diffusion in the matrix. It is shown that coarsening may occur by ,fault migration and annihilation but the effects of. interface kinetics, surface energy anisotropy and stress are also considered. (71 / 1/ 102)
COMPOSITES December 197i
Proceedings, 14th Japan Congress on Materials Research, Kyoto, pp 115119 (1971)
Reactivity of carbon fibres to oxidation by carbon dioxide
Shape instabilities of eutectic composites at elevated temperatures
256
Fujii, T., Mizukawa, K. and Zako, M.
Ultrasonic inspection of a boron/epoxyaluminium composite panel
Non-destructive testing of graphite fiber composite strucfures
T h e ndt o f three graphite fibre composite aircraft components is described. T h e ways in which radiographic and ultrasonic testing were used as positive checking methods are described in detail for each component. T h e feasibility o f using acoustic emission tests and thermal or infra-red tests was also studied. T h e kinds of fault for which each method is most effective are listed. (71/1/98)
The study of a non-destructiott testing method of fibreglass reinforced plastics (FRP) (acoustic method)
19, No 6, p 481 (June 1971)
Vibration response: a non-destructive test for fatigue crack damage in filament-reinforced composites
Schultz, A. B. and Warwick, D. N.
Journal of Composite Materials, Vol 5, pp 394-404 (July 1971) Laminated, filament-reinforced epoxy beam specimens were fatigued in vibratory flexure. The complex modulus was measured periodically as fatigue c r a c k damage accumulated. Changes in the modulus correlated well with the amount of crack damage. Measurement of these vibration response changes shows promise as a means of non-destructive monitoring of the integrity of a composite structural member during service. (71/1/106) Viscoelastic system
stresses
in
a
composite
Hackett, R. M. Polymer Engineering and Science, Vol 11, No 3, p 220 (May 1971) An analysis of the stress distribution is presented for a composite material in which one of the components exhibits time dependent properties. Examination of the mathematical
Mortimer, J. The Engineer, p 26 (24
June 1971) T h e types of carbon fibre and resin available are examined and the methods of using them in current engineering practice are discussed. T h e roles of carbon fibres in shafting and blading in general and in the development of the RB211 in particular are discussed. (71/1/95) The mechanical performance of cromplied composites
Lavengood,
R.
E.
and
Ishai,
O.
Polymer Engineering and Scie~nce, Vol 11, No 3, p 226 (May 1971) T h e tensile behaviour of glass-fibre/ epoxy cross-plied laminates was investigated for both brittle and ductile matrices and it was found that in both types of of system the laminae showed higher strength, stiffness and toughness than equivalent unidirectional composites. In the case o f 90°-0 ° systems the use of a ductile matrix resulted in a marked increase in strength with only a slight decrease in stiffness with the initial cracking stress nearly doubled. This could mean that a t virtually no extra cost the usable strength would be doubled for some applications. (71/1 ]96) Mechanical properties of stressgraphitized carbon libers: thermally induced relaxation and recovery
Shrian, S. and Strong, S. L. Fibre
Science and Technology, Vol 4, No 1, p 67 (July 1971) High modulus carbon fibres produced from a rayon precursor by stretching at high temperatures showed changes i n dimensions and properties when heated above 700°(3 without an externally applied stress. Low temperature annealing was found to induce structural changes by reason of a relaxation in the graphite layer planes with an accompanying reduction in mechanical property values. Stress-graphitized fibres subjected to further h e a t i n g above 2400°C were found to undergo further graphitization and to become stabilized. (71/1/97)
Plasticity and initiation of fracture in crystals with non-deforming inclusions
Tanaka, K., Mori, T. and Nakamura,
T. Proceedings, 14th Japan Congress on Materials Research, Kyoto, pp 52-56 (1971) Non-deforming inclusions such as particles or fibres of a strong material can be used to reinforce metals. From theoretical considerations of the elastic state and thermodynamic stability of such composites expressions are derived for the work hardening behaviour and fracture initiation of the material. (71 / 1/ 99)
Pultrusion - - a growing topnage market for reinforced plastics end products
Brandt Galsworthy, W. Reinforced Plastics, Vol 15, No 6, p 134 (June 1971) T h e progress of pultrusion is traced and the technical aspects of radio frequency curing are examined in view of its influence on the development of the process. It is concluded that the process will he a strong contender in the market for structural rofiles principally because the very igh pressures needed to form large cross sections in traditional materials such as metals are not required in pultrusion. (71/1 / 100)
~
A new method is proposed for testing FRP. This involves simultaneous recording of sonic vibrations at various selected points and measurement of strain by suitably situated strain gauges. T h e test sample in this case was a closed cylinder filled with water under pressure. A theory is developed to predict its behaviour and a number of experiments have been carried out. Both 'sona-graph' and 'voice-print' type recordings have been made. More work is needed but wide future applications are foreseen. (71/1/103) A tension test for filamentary composites
Hancock, J. R. and Swanson, G. D.
Journal o] Composite Materials, Vol 5, pp 414-416 (July 1971) A description of a tensile test using a simple specimen rectangular crosssection. This test achieves accurate specimen alignment and failure in the gauge-length providing a valid test with economically small specimens. (71/1/104)
Mool,
D.
and
Stephenson,
R.
Materials Evaluation, Vol 29, No 7, pp 159-164 (July 1971)
Thorue, D.
T h e ability o f through-transmitted ultrasound to detect defects in a 10ply unidirectional b o r o n / e p o x y laminate bonded to aluminium face sheets was tested. Ultrasonic C-scans showed such defects. A variety of different faults w o u l d be detected and the technique is apparently an effective inspection method for this particular composite. (71/1 / 105)
J. and Price, A. J. Fibre Science and Technology, Vol 4, No 1, p 9 (July 1971) T w o types of carbon fibre were prepared from commercial acrylic fibre by oxidation in air and inert atmosphere pyrolysis at 1273 K in one case and in the other by the use of an additional treatment at 2773 K. Measurements of the reactivity of these fibres to oxidation by carbon dioxide were made by weight loss and showed that whilst the activation energies for the reaction was the same in both cases the fibres pyrolysed at 1273 K were approximately seven times as reactive as those subsequently heat treated at 2773 K. General surface smooth, ing and the development of an extensive micro-pore system was noted. (71/1 / 101)
Hagemaier, D. J., McFaul, H. J. and Moon, D. Materials Evaluation, Vol
Cline, H. E. Acta MetaUurgica, Vol
29, No 6, pp 133-140 (]u~e 1971)
In order to predict the stability and coarsening mechanisms in eutectic alloys, the growth of shape instabilities in a rod composite is calculated assuming that interface migration is driven by capillarity and controlled by diffusion in the matrix. It is shown that coarsening may occur by ,fault migration and annihilation but the effects of. interface kinetics, surface energy anisotropy and stress are also considered. (71 / 1/ 102)
COMPOSITES December 197i
Proceedings, 14th Japan Congress on Materials Research, Kyoto, pp 115119 (1971)
Reactivity of carbon fibres to oxidation by carbon dioxide
Shape instabilities of eutectic composites at elevated temperatures
256
Fujii, T., Mizukawa, K. and Zako, M.
Ultrasonic inspection of a boron/epoxyaluminium composite panel
Non-destructive testing of graphite fiber composite strucfures
T h e ndt o f three graphite fibre composite aircraft components is described. T h e ways in which radiographic and ultrasonic testing were used as positive checking methods are described in detail for each component. T h e feasibility o f using acoustic emission tests and thermal or infra-red tests was also studied. T h e kinds of fault for which each method is most effective are listed. (71/1/98)
The study of a non-destructiott testing method of fibreglass reinforced plastics (FRP) (acoustic method)
19, No 6, p 481 (June 1971)
Vibration response: a non-destructive test for fatigue crack damage in filament-reinforced composites
Schultz, A. B. and Warwick, D. N.
Journal of Composite Materials, Vol 5, pp 394-404 (July 1971) Laminated, filament-reinforced epoxy beam specimens were fatigued in vibratory flexure. The complex modulus was measured periodically as fatigue c r a c k damage accumulated. Changes in the modulus correlated well with the amount of crack damage. Measurement of these vibration response changes shows promise as a means of non-destructive monitoring of the integrity of a composite structural member during service. (71/1/106) Viscoelastic system
stresses
in
a
composite
Hackett, R. M. Polymer Engineering and Science, Vol 11, No 3, p 220 (May 1971) An analysis of the stress distribution is presented for a composite material in which one of the components exhibits time dependent properties. Examination of the mathematical