- Email: [email protected]
Mechanical and electrical properties of surface modified kaolinite-polyester particulate composites
Compression response of laminated composites containing an open hold Chang, F-K., Lessard, L. and Tang, J-M.
SAMPE Quarterly Vol 19 No 4 (July 1988) pp 46-51 An analytical model derived to predict the in-plane response of laminated composites, containing an open hole, to compressive loading is discussed. Results of experiments carried out on carbon fibre-reinforced epoxy (T300/976) laminates are presented and shown to give good agreement with calculations based on the model. The model can provide information on: the type and size of damage at a given load; the residual stiffness and strength of the laminate; the final collapse load; and the complete response of the laminate from initial loading to final collapse. Gas plasma treatment of Spectra fiber Kaplan, S. L., Rose, P. W., Nguyen, H. X. and Chang, H. W. SAMPE Quarterly Vo119
No 4 (July 1988) pp 55-59 The method of cold plasma treatment of surfaces is described. Results of tests on highly-oriented polyethylene fibres (Spectra 900 and 1000) before and after plasma treatment are given. Results of mechanical tests carried out on epoxy matrices reinforced with Spectra fibres after various treatments indicate that the interlaminar shear strength of Spectra reinforced epoxy is greatly improved by using plasma-treated fibres. A general boundary integral formulation for the anisotropic plate bending problems Shi, G. and Bezine, G. Journal of Composite
Materials Vo122 (August 1988) pp 694-716 A new direct boundary element method (DBEM) for the analysis of Kirchoff's anisotropic plate bending problems is presented. The formulation derives from the generalized Rayleigh-Green identity. The method can be used to analyse the flexure of anisotropic plates with any plan forms under arbitrary conventional boundary conditions, particularly for the plates with a boundary having some corner points. Numerical results presented show that the method has a satisfactory accuracy. A micromechanics model for the effective Young's modulus of a piecewise-isotropic laminate with wavy patterns Lee, J-W. and Harris, C. E. Journal of
Composite Materials Vo122 (August 1988) pp 717-741
in a single pre-stressed ply are considered using elementary micromechanics concepts and the results are integrated with classical lamination theory. The combined effects of fibre pre-loads thermally induced contractions/expansions and externally applied inplane loadings are considered. The model predicts that the macroscopic thermal tensile stresses can be completely eliminated by fibre pre-stressing. Review of methods for characterization of interracial fiber-matrix interaction Narkis, M., Chen, E. J. H. and Pipes, R. B.
Polymer Composites Vol 9 No 4 (August 1988) pp 245-251 Methods for studying fibre/matrix interaction: fibre pull-out tests; single filament critical length method; short beam shear test; and microdebonding test, are briefly reviewed (34 References). A bending jigs test, which does not depend upon the fibre tensile strength, is introduced and discussed. However, this test was still awaiting experimental verification. Elastic moduli and failure mechanism of composites made of spherical glass beads, of polyethylene using poly(4-vinylpyridine graft butylacrylate) as an interface agent Pegoraro, M., Severini, F. and Di Landro,
L. Polymer Composites Vol 9 No 4 (August 1988) pp 252-262 Mechanical properties, particularly stiffness and strength, of glass bead-reinforced polyethylene are reported. In some of the composites the glass beads were uncoated whereas in others they were coated with an adhesion promoter. Preparation of this promoter, a graft copolymer comprising polymeric chains of butylacrylate with lateral branches of poly(4-vinyipyridine) chains, is described. The composite containing the coated beads is shown to have a higher elastic modulus and higher tensile strength than that containing the uncoated beads. Theoretical predictions of the moduli are shown not to be in good agreement with experimental results except at low filler concentrations. This is attributed to the fact that the presence of the adhesion promoter had not been accounted for in the calculations. Measuring spatial orientation of short fiber reinforced thermoplastics by image analysis Fischer, G. and Eyerer, P. Polymer Compo-
sites Vol 9 No 4 (August 1988) pp 297-304
A mathematical model based on the Euler-Bernoulli beam theory is prposed for predicting the effective Young's moduli of piece-wise isotropic composite laminates with wavy patterns in the main load-carrying layers or wrinkled fibres. These were assumed to be corrugated beams embedded in elastic foundations of various spring constants. The effective moduli were experimentally determined and compared to predicted values. Close agreement was obtained.
A computer-based measuring strategy to determine spatial orientation of short glass fibres from the cross-section of single fibres is presented. A practicable way of correcting the inclination-dependent probability of hitting a fibre is shown, as well as the correction of fibre end intersections. The latter is done by pattern recognition and application of a set of FORTRAN subroutines. A simple model which allows the approximate calculation of thermal expansion as a function of volume content and fibre orientation is also presented. This serves as an applicability test for the measuring system. (Authors abstract)
A mechanical/thermal analysis of pre-stressed composite laminates Tuttle, M. E. Journal of Composite Materials
Transverse thermal expansion coefficients for composite laminates Wetherhold, R. C. and Boss, C. S. Journal
Vol 22 (August 1988) pp 780-792
of Composite Materials Vol 22 (September 1988) pp 818-817
A simple model is proposed to predict the effects of pre-stresses within a composite laminate. The fibre and matrix stress induced
COMPOSITES. MAY 1989
A specific derivation, similar to that of Pagano, for transverse thermal expansion
coefficients is presented. A dominant term in the resulting expressions was invariant with respect to lamina orientation and served as a stabilizing term. This limits the flexibility available to the designer to achieve arbitrary transverse expansion coefficients. Some bounds on the transverse expansion coefficient are suggested. A simple model for the compressive failure of weakly bonded, fiber-reinforced composites Steif, P. S. Journal of Composite Materials
Vo122 (September 1988) pp 818-828 A model which explains the low compressive strength of composites made of brittle constituents is presented. The equilibrium equation for the longitudinally loaded fibre is derived directly (as opposed to using energy methods) permitting the inclusion of an upper limit on interfacial shear stress. The response of such a composite to an imperfection is then studied. The theory leads to values of compressive strength which are more representative of real composites. However, the sensitivity of the compressive strength to fibre misalignment and interracial shear strength is overestimated. Reinforcing mechanism by small diameter fiber in short fiber composite Sato, N., Kurauchi, T., Shigeyuki, S. and Kamigaito, O. Journal of Composite Mate-
rials Vol 22 (September 1988) pp 850-873 The influence of fibre diameters smaller (7 ~m, 4 ~m and 0.5 ~m) than the diameter of conventional fibres on the mechanical properties of a composite is reported in this paper. It was found that the composite strengths and toughnesses increased as the diameter was decreased, except for very small diameter fibres. The initiation and propagation of microcracks at the fibre/ matrix interface was strongly suppressed by small diameter fibres. A model which can explain the presence of an optimum fibre diameter is proposed. Tensor tranformations and failure criteria for the analysis of fiber composite materials Christensen, R. M. Journal of Composite
Materials Vol 22 (September 1988) pp 874-897 A fully three dimensional lamination theory applicable to thick laminates involving outof-plane stress terms is derived with appropriate tensor transformations. A new failure criterion is derived which involves a minimum number of failure parameters. The criterion is evaluated with respect to failure data. Mechanical and electrical properties of surface modified kaolinite-polyester particulate composites Jalajakumari, B., Warrier, K. G. K., Satyanarayana, K. G. and Pavithran, C.
Journal of Reinforced Plastics and Composites Vol 7 (September 1988) pp 402-412 The effects of surface modified and unmodified clay particles incorporated into a polyester resin on the mechanical and electrical properties of the composite are investigated and compared with those of the matrix. It was found that composites containing modified clays showed higher densities, higher compressive stresses, better abrasion resistance and higher electrical resistivity compared to the unmodified clay composites.
291
SAMPE Quarterly Vol 19 No 4 (July 1988) pp 46-51 An analytical model derived to predict the in-plane response of laminated composites, containing an open hole, to compressive loading is discussed. Results of experiments carried out on carbon fibre-reinforced epoxy (T300/976) laminates are presented and shown to give good agreement with calculations based on the model. The model can provide information on: the type and size of damage at a given load; the residual stiffness and strength of the laminate; the final collapse load; and the complete response of the laminate from initial loading to final collapse. Gas plasma treatment of Spectra fiber Kaplan, S. L., Rose, P. W., Nguyen, H. X. and Chang, H. W. SAMPE Quarterly Vo119
No 4 (July 1988) pp 55-59 The method of cold plasma treatment of surfaces is described. Results of tests on highly-oriented polyethylene fibres (Spectra 900 and 1000) before and after plasma treatment are given. Results of mechanical tests carried out on epoxy matrices reinforced with Spectra fibres after various treatments indicate that the interlaminar shear strength of Spectra reinforced epoxy is greatly improved by using plasma-treated fibres. A general boundary integral formulation for the anisotropic plate bending problems Shi, G. and Bezine, G. Journal of Composite
Materials Vo122 (August 1988) pp 694-716 A new direct boundary element method (DBEM) for the analysis of Kirchoff's anisotropic plate bending problems is presented. The formulation derives from the generalized Rayleigh-Green identity. The method can be used to analyse the flexure of anisotropic plates with any plan forms under arbitrary conventional boundary conditions, particularly for the plates with a boundary having some corner points. Numerical results presented show that the method has a satisfactory accuracy. A micromechanics model for the effective Young's modulus of a piecewise-isotropic laminate with wavy patterns Lee, J-W. and Harris, C. E. Journal of
Composite Materials Vo122 (August 1988) pp 717-741
in a single pre-stressed ply are considered using elementary micromechanics concepts and the results are integrated with classical lamination theory. The combined effects of fibre pre-loads thermally induced contractions/expansions and externally applied inplane loadings are considered. The model predicts that the macroscopic thermal tensile stresses can be completely eliminated by fibre pre-stressing. Review of methods for characterization of interracial fiber-matrix interaction Narkis, M., Chen, E. J. H. and Pipes, R. B.
Polymer Composites Vol 9 No 4 (August 1988) pp 245-251 Methods for studying fibre/matrix interaction: fibre pull-out tests; single filament critical length method; short beam shear test; and microdebonding test, are briefly reviewed (34 References). A bending jigs test, which does not depend upon the fibre tensile strength, is introduced and discussed. However, this test was still awaiting experimental verification. Elastic moduli and failure mechanism of composites made of spherical glass beads, of polyethylene using poly(4-vinylpyridine graft butylacrylate) as an interface agent Pegoraro, M., Severini, F. and Di Landro,
L. Polymer Composites Vol 9 No 4 (August 1988) pp 252-262 Mechanical properties, particularly stiffness and strength, of glass bead-reinforced polyethylene are reported. In some of the composites the glass beads were uncoated whereas in others they were coated with an adhesion promoter. Preparation of this promoter, a graft copolymer comprising polymeric chains of butylacrylate with lateral branches of poly(4-vinyipyridine) chains, is described. The composite containing the coated beads is shown to have a higher elastic modulus and higher tensile strength than that containing the uncoated beads. Theoretical predictions of the moduli are shown not to be in good agreement with experimental results except at low filler concentrations. This is attributed to the fact that the presence of the adhesion promoter had not been accounted for in the calculations. Measuring spatial orientation of short fiber reinforced thermoplastics by image analysis Fischer, G. and Eyerer, P. Polymer Compo-
sites Vol 9 No 4 (August 1988) pp 297-304
A mathematical model based on the Euler-Bernoulli beam theory is prposed for predicting the effective Young's moduli of piece-wise isotropic composite laminates with wavy patterns in the main load-carrying layers or wrinkled fibres. These were assumed to be corrugated beams embedded in elastic foundations of various spring constants. The effective moduli were experimentally determined and compared to predicted values. Close agreement was obtained.
A computer-based measuring strategy to determine spatial orientation of short glass fibres from the cross-section of single fibres is presented. A practicable way of correcting the inclination-dependent probability of hitting a fibre is shown, as well as the correction of fibre end intersections. The latter is done by pattern recognition and application of a set of FORTRAN subroutines. A simple model which allows the approximate calculation of thermal expansion as a function of volume content and fibre orientation is also presented. This serves as an applicability test for the measuring system. (Authors abstract)
A mechanical/thermal analysis of pre-stressed composite laminates Tuttle, M. E. Journal of Composite Materials
Transverse thermal expansion coefficients for composite laminates Wetherhold, R. C. and Boss, C. S. Journal
Vol 22 (August 1988) pp 780-792
of Composite Materials Vol 22 (September 1988) pp 818-817
A simple model is proposed to predict the effects of pre-stresses within a composite laminate. The fibre and matrix stress induced
COMPOSITES. MAY 1989
A specific derivation, similar to that of Pagano, for transverse thermal expansion
coefficients is presented. A dominant term in the resulting expressions was invariant with respect to lamina orientation and served as a stabilizing term. This limits the flexibility available to the designer to achieve arbitrary transverse expansion coefficients. Some bounds on the transverse expansion coefficient are suggested. A simple model for the compressive failure of weakly bonded, fiber-reinforced composites Steif, P. S. Journal of Composite Materials
Vo122 (September 1988) pp 818-828 A model which explains the low compressive strength of composites made of brittle constituents is presented. The equilibrium equation for the longitudinally loaded fibre is derived directly (as opposed to using energy methods) permitting the inclusion of an upper limit on interfacial shear stress. The response of such a composite to an imperfection is then studied. The theory leads to values of compressive strength which are more representative of real composites. However, the sensitivity of the compressive strength to fibre misalignment and interracial shear strength is overestimated. Reinforcing mechanism by small diameter fiber in short fiber composite Sato, N., Kurauchi, T., Shigeyuki, S. and Kamigaito, O. Journal of Composite Mate-
rials Vol 22 (September 1988) pp 850-873 The influence of fibre diameters smaller (7 ~m, 4 ~m and 0.5 ~m) than the diameter of conventional fibres on the mechanical properties of a composite is reported in this paper. It was found that the composite strengths and toughnesses increased as the diameter was decreased, except for very small diameter fibres. The initiation and propagation of microcracks at the fibre/ matrix interface was strongly suppressed by small diameter fibres. A model which can explain the presence of an optimum fibre diameter is proposed. Tensor tranformations and failure criteria for the analysis of fiber composite materials Christensen, R. M. Journal of Composite
Materials Vol 22 (September 1988) pp 874-897 A fully three dimensional lamination theory applicable to thick laminates involving outof-plane stress terms is derived with appropriate tensor transformations. A new failure criterion is derived which involves a minimum number of failure parameters. The criterion is evaluated with respect to failure data. Mechanical and electrical properties of surface modified kaolinite-polyester particulate composites Jalajakumari, B., Warrier, K. G. K., Satyanarayana, K. G. and Pavithran, C.
Journal of Reinforced Plastics and Composites Vol 7 (September 1988) pp 402-412 The effects of surface modified and unmodified clay particles incorporated into a polyester resin on the mechanical and electrical properties of the composite are investigated and compared with those of the matrix. It was found that composites containing modified clays showed higher densities, higher compressive stresses, better abrasion resistance and higher electrical resistivity compared to the unmodified clay composites.
291