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Bonding of particles of metallic powders compacted by explosives
formation data. Variational theorems were also used to show this analysis to be more accurate than previous solutions. Study on fiexural vibration of triangular composite plates influenced by fibre orientation Liew, K.M., Lam, K.Y. and Chow, S.T. Composite Structures Vol 13 No 2 (1989) pp 123-132 This paper describes the use of a computationally efficient and accurate numerical method, to investigate the effect of fibre orientation, plate aspect ratio and boundary conditions on the flexural vibrations of triangular composite plates. The Gram-Schmidt orthogonalization process in the RayleighRitz procedure is used to determine the natural frequencies of the plates. The authors report that the results obtained in this investigation compare favourably with existing numerical and analytical results. A study on the buckling behaviour of an orthotropic square plate with a central circular hole Lee, Y.J., Lin, H.J. and Lin, C.C. Composite Structures Vo113 No 3 (1989) pp 173-188 This paper describes the finite elemental analysis of the buckling behaviour of orthotropic square plates, with or without a central circular hole. The effect of othotropy is examined. Both uniaxial and biaxial compression are considered for various boundary conditions. The authors report that for highly orthotropic material under uniaxial or biaxial compression in the weaker direction, there is a tendency for the lowest buckling mode not to be a single half-wave. It is found that the first buckling mode may be two or three half-waves, depending on the degree of orthotropy as well as boundary conditions. The characteristics of buckling strength and mode shape of orthotropic plates with central circular holes are presented and discussed in this paper. •
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Sublammate analysis of mterlammar fracture in composites: Part I - Analytical model Armanios, E.A. and Rehfield, L.W. Journal o f Composites Technology and Research Vol 11 No 4 (1989) pp 135-146 A simple model was developed for the analysis of mixed mode edge delamination specimens, this was based upon transverse shear deformation theory and a sublaminate approach. This provided closed form estimates of the interlaminar shear stresses ahead of the crack, the total strain energy release rate and the individual components of the strain energy release rate. Controlling parameters were identified. Sublaminate analysis of interlaminar i'racture in composites: Part II - Applications Armanios, E.A. and Rehfield, L.W. Journal o f Composites Technology and Research Vol 11 No 4 (1989) pp 147-153 The sublaminate analysis developed in part I for mixed mode edge delamination specimens was compared with predictions from quasi-three-dimensional finite element analysis and classical plate theory for 58 test cases. Predictions from the sublaminate analysis follow the same trends as the finite element solutions and are mostly in good agreement. The analysis was simple enough to perform on a desk top computer.
358
COMPOSITES
. JULY
1990
Synthesis and characterisation of glycidyl methacrylate/styrene copolymers and determination of monomer reactivity ratios Soundararajan, S., Reddy, B.S.R. and Rajadural, S. Polymer Vol 31 No 2 (1990) pp 366-370 The synthesis, characterization and reactivity ratios of copolymers of diglycidyl methacrylate (GMA) and styrene are presented. The copolymers are of interest as adhesives which possess colour stability for leather to leather and leather to rubber bonding. The techniques of infra-red and 13C nuclear magnetic resonance spectroscopy, elemental analysis, gel permeation chromatography, thermogravimetric analysis and differential scanning calorimetry are employed. Copolymer reactivity ratios are calculated using the KelenTudos method. Adhesive and curing studies on the copolymers are reported elsewhere.
and fibre orientation affect the natural frequencies of free-vibration plates using the orthogonalization process.
METAL MA TRICES Analysis of tensile properties for a whiskerreinforced metal-matrix composite Tvergaard, V. Acta Metallurgica et Materialia Vo138 No 2 (1990) pp 185-194 Short fibre reinforcement of a ductile metal has been analysed using a micro-mechanical model. Alignment of the fibres has been assumed to have been introduced during the processing. A periodic array of fibres has been used for the numerical analysis using a representative unit cell. Varying the degree of elasticity in the fibres revealed that the overall stress-strain behaviour is dominated by the matrix plasticity. Uniaxial tension in the fibre direction was primarily considered but triaxiality was also investigated. The effect of fibre volume fraction, fibre length and spacing was determined.
A theory for progressive matrix cracking in composite laminates Tan, S.C. and Nuismer, R.J. Journal of Composite Materials Vo123 No 10 (1989) pp 1029-1047 Fracture mechanics and elasticity theory are used to model the progressive matrix cracking of composite laminates containing a cracked 90° ply under uniaxial tension or shear loading. Laminate stiffness and Poisson's ratio were solved as a function of crack density or load level. It was stated that the mechanical and thermal properties required for the analysis may be obtained from uniaxial ply testing. Four typical graphite/epoxy and glass/epoxy systems were used to test the model and showed a good agreement.
Bonding of particles of metallic powders compacted by explosives Alvarez, G., Gonzalez, A.C. and Cuyas, J.C. Powder Metallurgy Vol 32 No 1 (1989) pp 53-64 Explosive bonding of powder compacts was investigated with iron and copper powders. Metallographic analyses showed the prevailing joining mechanism in the copper to be the breaking down of the surface oxide layer promoting the formation of weld bridges. In iron compacts the bond was found to be mechanical in nature.
Thermal buckling behaviour of laminated composite plates with temperature-dependent properties Lien-wen Chen, and Lei-Yi Chen Composite Structures Vo113 No 4 (1989) pp 275-287 This paper describes the investigation of the thermal buckling behaviour of composite laminated plates subjected to a uniform temperature field by the finite element method. Temperature-dependent elastic and thermal properties are considered. The stiffness and geometry matrices are derived based on the principle of minimum potential energy. The authors use an iterative procedure to determine the thermal buckling load and show by numerical results that the influence of temperature-dependent mechanical properties on the thermal buckling behaviour is significant.
Crack initiation and growth toughness of an aluminium metal-matrix composite Manoharan, M. and Lewandowski, J.J. Acta Metallurgica et Materialia Vo138 No 3 (1990) pp 489-496 An AI-Zn-Mg-Cu alloy reinforced with 0, 15 and 20% (by volume) of SiC particles was investigated to study the effect of systematic changes in the matrix microstructure. Varying degrees of heat treatments were used to attain the underaged and averaged conditions of equivalent matrix microhardness and flow stress. This difference in ageing had a significant effect on both the tearing modulus and J~c, a measure of fracture initiation and growth toughness. SEM and TEM were utilized to rationalize the results in light of existing theories of ductile fracture propagation.
Two-dimensional orthogonai polynomials for vibration of rectangular composite plates Lam, K.Y., Liew, K.M. and Chow, S.T. Composite Structures Vol 13 No 4 (1989) pp 239-250 This paper describes the use of the twodimensional orthogonal plate function generated by the Gram-Schmidt orthoganalization process in the Rayleigh-Ritz procedure which has been used to study the vibration of composite plates. The effect of fibre orientation on the vibration behaviour of rectangular single-layer, parallel-fibre plates with various combinations of boundary conditions is studied. The paper presents some numerical methods in the literature. This paper shows how the boundary conditions, aspect ratio
Formation of non-equilibrium dihedral angles in composite materials Lisovsky, A.F. International Journal o f Powder Metallurgy Vol 26 No 1 (1990) pp 45-49 Two classes of composite materials consisting of high melting point grains and a binder are shown to occur during tests on sintered WCCo, TiC-Fe, TiC-Co, WC-Cu, Cr3C2-Cu and Ni-Pb composites (with WC, TiC, Cr3C 2 and Ni as the high melting phase in each case). In the first class, nonequilibrium dihedral angles are formed in predominance, whilst in the second class, equilibrium dihedral angles are predominantly formed. The first class of composites is characteristically able to imbibe metal melts, whilst the second class of cam-
•
•~
•
Sublammate analysis of mterlammar fracture in composites: Part I - Analytical model Armanios, E.A. and Rehfield, L.W. Journal o f Composites Technology and Research Vol 11 No 4 (1989) pp 135-146 A simple model was developed for the analysis of mixed mode edge delamination specimens, this was based upon transverse shear deformation theory and a sublaminate approach. This provided closed form estimates of the interlaminar shear stresses ahead of the crack, the total strain energy release rate and the individual components of the strain energy release rate. Controlling parameters were identified. Sublaminate analysis of interlaminar i'racture in composites: Part II - Applications Armanios, E.A. and Rehfield, L.W. Journal o f Composites Technology and Research Vol 11 No 4 (1989) pp 147-153 The sublaminate analysis developed in part I for mixed mode edge delamination specimens was compared with predictions from quasi-three-dimensional finite element analysis and classical plate theory for 58 test cases. Predictions from the sublaminate analysis follow the same trends as the finite element solutions and are mostly in good agreement. The analysis was simple enough to perform on a desk top computer.
358
COMPOSITES
. JULY
1990
Synthesis and characterisation of glycidyl methacrylate/styrene copolymers and determination of monomer reactivity ratios Soundararajan, S., Reddy, B.S.R. and Rajadural, S. Polymer Vol 31 No 2 (1990) pp 366-370 The synthesis, characterization and reactivity ratios of copolymers of diglycidyl methacrylate (GMA) and styrene are presented. The copolymers are of interest as adhesives which possess colour stability for leather to leather and leather to rubber bonding. The techniques of infra-red and 13C nuclear magnetic resonance spectroscopy, elemental analysis, gel permeation chromatography, thermogravimetric analysis and differential scanning calorimetry are employed. Copolymer reactivity ratios are calculated using the KelenTudos method. Adhesive and curing studies on the copolymers are reported elsewhere.
and fibre orientation affect the natural frequencies of free-vibration plates using the orthogonalization process.
METAL MA TRICES Analysis of tensile properties for a whiskerreinforced metal-matrix composite Tvergaard, V. Acta Metallurgica et Materialia Vo138 No 2 (1990) pp 185-194 Short fibre reinforcement of a ductile metal has been analysed using a micro-mechanical model. Alignment of the fibres has been assumed to have been introduced during the processing. A periodic array of fibres has been used for the numerical analysis using a representative unit cell. Varying the degree of elasticity in the fibres revealed that the overall stress-strain behaviour is dominated by the matrix plasticity. Uniaxial tension in the fibre direction was primarily considered but triaxiality was also investigated. The effect of fibre volume fraction, fibre length and spacing was determined.
A theory for progressive matrix cracking in composite laminates Tan, S.C. and Nuismer, R.J. Journal of Composite Materials Vo123 No 10 (1989) pp 1029-1047 Fracture mechanics and elasticity theory are used to model the progressive matrix cracking of composite laminates containing a cracked 90° ply under uniaxial tension or shear loading. Laminate stiffness and Poisson's ratio were solved as a function of crack density or load level. It was stated that the mechanical and thermal properties required for the analysis may be obtained from uniaxial ply testing. Four typical graphite/epoxy and glass/epoxy systems were used to test the model and showed a good agreement.
Bonding of particles of metallic powders compacted by explosives Alvarez, G., Gonzalez, A.C. and Cuyas, J.C. Powder Metallurgy Vol 32 No 1 (1989) pp 53-64 Explosive bonding of powder compacts was investigated with iron and copper powders. Metallographic analyses showed the prevailing joining mechanism in the copper to be the breaking down of the surface oxide layer promoting the formation of weld bridges. In iron compacts the bond was found to be mechanical in nature.
Thermal buckling behaviour of laminated composite plates with temperature-dependent properties Lien-wen Chen, and Lei-Yi Chen Composite Structures Vo113 No 4 (1989) pp 275-287 This paper describes the investigation of the thermal buckling behaviour of composite laminated plates subjected to a uniform temperature field by the finite element method. Temperature-dependent elastic and thermal properties are considered. The stiffness and geometry matrices are derived based on the principle of minimum potential energy. The authors use an iterative procedure to determine the thermal buckling load and show by numerical results that the influence of temperature-dependent mechanical properties on the thermal buckling behaviour is significant.
Crack initiation and growth toughness of an aluminium metal-matrix composite Manoharan, M. and Lewandowski, J.J. Acta Metallurgica et Materialia Vo138 No 3 (1990) pp 489-496 An AI-Zn-Mg-Cu alloy reinforced with 0, 15 and 20% (by volume) of SiC particles was investigated to study the effect of systematic changes in the matrix microstructure. Varying degrees of heat treatments were used to attain the underaged and averaged conditions of equivalent matrix microhardness and flow stress. This difference in ageing had a significant effect on both the tearing modulus and J~c, a measure of fracture initiation and growth toughness. SEM and TEM were utilized to rationalize the results in light of existing theories of ductile fracture propagation.
Two-dimensional orthogonai polynomials for vibration of rectangular composite plates Lam, K.Y., Liew, K.M. and Chow, S.T. Composite Structures Vol 13 No 4 (1989) pp 239-250 This paper describes the use of the twodimensional orthogonal plate function generated by the Gram-Schmidt orthoganalization process in the Rayleigh-Ritz procedure which has been used to study the vibration of composite plates. The effect of fibre orientation on the vibration behaviour of rectangular single-layer, parallel-fibre plates with various combinations of boundary conditions is studied. The paper presents some numerical methods in the literature. This paper shows how the boundary conditions, aspect ratio
Formation of non-equilibrium dihedral angles in composite materials Lisovsky, A.F. International Journal o f Powder Metallurgy Vol 26 No 1 (1990) pp 45-49 Two classes of composite materials consisting of high melting point grains and a binder are shown to occur during tests on sintered WCCo, TiC-Fe, TiC-Co, WC-Cu, Cr3C2-Cu and Ni-Pb composites (with WC, TiC, Cr3C 2 and Ni as the high melting phase in each case). In the first class, nonequilibrium dihedral angles are formed in predominance, whilst in the second class, equilibrium dihedral angles are predominantly formed. The first class of composites is characteristically able to imbibe metal melts, whilst the second class of cam-