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axial loads
Literature survey Prepared by M.R. Alexander, J. Collins, J.D. Hague and A.J. Hosty, University of Sheffield, UK
CEMENT MA TRICES Comparative tests on plain, fabric reinforced and steel reinforced concrete ground slabs Beckett, D. Concrete Vo124 No 3 (1990) pp 43-45 A test programme is developed to compare the mechanical behaviour of plain, fabric reinforced and steel fibre reinforced concrete ground slabs. Slabs are loaded hydraulically by means of a hand pump and deflections are recorded by means of dial gauges along two centre lines at 20 kN load increments. Best results are obtained when Dramix (60/80) steel fibre reinforcement is used at a dosage of 30 kg m 3. An increase in cracking load of over 60% for this slab compared to an unreinforced slab is recorded. The test programme is continuing.
the interfacial shear stress to be evaluated in the analysis.
A theory for creep by interfacial flaw growth in ceramics and ceramic composites Suresh, S. and Brockenbrough, J.R. Acta Metallurgica et Materialia Vo138 No I (1990) pp 55--68 In this paper the creep behaviour of elastic solids deforming by the growth of intergranular or interfacial flaws has been analytically treated. The stress exponent within the power-law creep regime was derived using the changes in elastic moduli induced by the growth of internal damage. Explicit expressions are provided for the derivation of creep exponents for several microcrack geometries, microcrack growth criteria and a wide range of creep times from steady, to non steady state conditions. General solutions for the creep strain rates are also discussed for flaw growth rates given by a power law dependence on the applied stress.
CERAMIC FIBRES GENERAL Experimental tests for damping measurements on several short glass fiber composites Crema, L.B., Castellani, A. and Serra, A. Journal o f Composite Materials Vo123 No 10 (1989) pp 978-987 Vibrational damping properties of short glass fibre composites were evaluated experimentally with road transport applications in mind. Longitudinal, transverse and randomly aligned specimens were tested with their damping responses compared to those theoretically predicted. These were determined using a continuous fibre model extended to deal with short fibre reinforcement. A good agreement was found validating this approach, with the results also confirming the close relationship perceived to exist between damping and stiffness characteristics in glass fibre composites.
parameters while designing the composite shells
Buckling of edge-damaged filament-wound composite cylindrical shells under combined torsional/axial loads Stavsky, Y., Greenberg, J.B. and Sabag, M. Composite Structures Vol 13 No 1 (1989) pp 21-34 This paper describes the use of a finite complex Fourier transform combined with a displacement function to solve displacement equilibrium equations, based on Flugge's quasi-linear theory, to analyse the stability of filament wound composite cylindrical shells under combined torsional/axial loading. Results from this model indicate that for isotropic shells the sensitivity to edge damage decreased with lower applied axial loads irrespective of the direction of the applied torque. However, for anisotropic shells certain torques can increase the critical axial load sustainable. This result is unaffected by the presence of edge damage, and can desensitize the shell to edge damage over a larger section of its circumference.
CERAMIC MA TRICES
Analysis of the localized buckling in composite plate structures with applications to determining the strength of corrugated fibreboard Johnson, M.W. and Urbanik, T.J. Journal of Composites Technology and Research Vo111 No 4 (1989) pp 121-128 This paper provides an analysis for the local buckling instability of structural sections with flat plate elements under compression. Preexisting theories for linear isotropic elastic materials were extended to include nonlinear anisotropic elastic materials. Using the developed theory, equations were derived for the stiffness of a single plate element under uniaxial compression. A non-linear finite element analysis was used to calculate the critical buckling load, critical buckling strain and stiffness coefficients for arbitrary sections. This analysis was then applied to fibreboard under compression.
Buckling of thick layered composite plates under inplane moment loading Singh, G., Sadasiva Rap, Y.V.K. and lyengar, N.G.R. Composite Structures Vo113 No 1 (1989) pp 35-48 In this paper a first order shear deformation laminate theory that accounts for the Green Lagrange strain vector is described and its finite element model is developed. This element is used to study the effects of anisotropy, transverse shear modulus, aspect ratio and boundary conditions on buckling behaviour under in plane triangular loading. It is observed that for an angle ply thick plate, maximum load occurs at + / - 15°, whereas for thin plate it occurs at + / - 30°. The authors also report that aspect ratio, boundary conditions and transverse shear significantly affect the buckling load.
Evaluation of the interfacial shear strength, residual clamping stress and coefficient of friction for fiber-reinforced ceramic composites Hsueh, C-H. Acta Metallurgica et Materialia Vol38 No 3 (1990) pp 403-409 The interracial shear strength, residual clamping stress and coefficient of friction at the fibre/matrix interface were evaluated for fibre reinforced ceramic composites, Theoretical analysis of fibre push-out and corresponding experimental results from the SiCRBSN system were used in the analysis. The shear stress was evaluated from the stress at which the debonding initiated after which sliding occurred. With fibres having a Poisson's ratio greater than zero, the characteristics of the nonlinear relationship between the load to push out the fibre and the sample thickness enabled the residual clamping stress, the coefficient of friction and
Axisymmetric stresses in buried thin orthotropic cylindrical shells due to p-wave loading Rap, P.V.M., Singh, V.P. and Upadhyay, P.C. Composite Structures Vo113 No 3 (1989) pp 209-216 This paper is concerned with the study of stresses (axial and hoop) induced in a buried infinite orthotropic cylindrical shell, when it is excited by a p-wave travelling in the surrounding ground. A thin shell theory formulation has been used and only axisymmetric behaviour of the shell has been investigated. The shell is assumed to be perfectly bonded to the surrounding medium of infinite extent. The relative influence of the variation of orthotropy parameters on the stresses in the shell has been studied for different angles of incidence of the p-wave. Results have been obtained for different soil conditions--hard (rocky), medium hard and soft. It is realized that the stresses in the shell can be considerably reduced by adjusting the orthotropy
Comparison between shear deformable and Kirchoff theories for bending, buckling and vibration of antisymmetric angle-ply laminated plates Khdeir, A.A. Composite Structures Vol 13 No 3 (1989) pp 159-172 This paper presents a generalized Levy-type solution in conjunction with the state space concept developed for the bending, buckling and vibration of antisymmetric angle-ply laminated plates. The exact solutions are applicable to rectangular plates with two opposite edges simply supported and the remaining ones subjected to a combination of clamped, simply supported and free boundary conditions. The solutions are obtained for the classical Kirehoff theory and the numerical results are compared with their counterparts using the first order transverse shear deformation theory. The comparisons show that the results obtained within the classical laminated theory can be significantly inaccurate.
C O M P O S I T E S . J U L Y 1990
355
CEMENT MA TRICES Comparative tests on plain, fabric reinforced and steel reinforced concrete ground slabs Beckett, D. Concrete Vo124 No 3 (1990) pp 43-45 A test programme is developed to compare the mechanical behaviour of plain, fabric reinforced and steel fibre reinforced concrete ground slabs. Slabs are loaded hydraulically by means of a hand pump and deflections are recorded by means of dial gauges along two centre lines at 20 kN load increments. Best results are obtained when Dramix (60/80) steel fibre reinforcement is used at a dosage of 30 kg m 3. An increase in cracking load of over 60% for this slab compared to an unreinforced slab is recorded. The test programme is continuing.
the interfacial shear stress to be evaluated in the analysis.
A theory for creep by interfacial flaw growth in ceramics and ceramic composites Suresh, S. and Brockenbrough, J.R. Acta Metallurgica et Materialia Vo138 No I (1990) pp 55--68 In this paper the creep behaviour of elastic solids deforming by the growth of intergranular or interfacial flaws has been analytically treated. The stress exponent within the power-law creep regime was derived using the changes in elastic moduli induced by the growth of internal damage. Explicit expressions are provided for the derivation of creep exponents for several microcrack geometries, microcrack growth criteria and a wide range of creep times from steady, to non steady state conditions. General solutions for the creep strain rates are also discussed for flaw growth rates given by a power law dependence on the applied stress.
CERAMIC FIBRES GENERAL Experimental tests for damping measurements on several short glass fiber composites Crema, L.B., Castellani, A. and Serra, A. Journal o f Composite Materials Vo123 No 10 (1989) pp 978-987 Vibrational damping properties of short glass fibre composites were evaluated experimentally with road transport applications in mind. Longitudinal, transverse and randomly aligned specimens were tested with their damping responses compared to those theoretically predicted. These were determined using a continuous fibre model extended to deal with short fibre reinforcement. A good agreement was found validating this approach, with the results also confirming the close relationship perceived to exist between damping and stiffness characteristics in glass fibre composites.
parameters while designing the composite shells
Buckling of edge-damaged filament-wound composite cylindrical shells under combined torsional/axial loads Stavsky, Y., Greenberg, J.B. and Sabag, M. Composite Structures Vol 13 No 1 (1989) pp 21-34 This paper describes the use of a finite complex Fourier transform combined with a displacement function to solve displacement equilibrium equations, based on Flugge's quasi-linear theory, to analyse the stability of filament wound composite cylindrical shells under combined torsional/axial loading. Results from this model indicate that for isotropic shells the sensitivity to edge damage decreased with lower applied axial loads irrespective of the direction of the applied torque. However, for anisotropic shells certain torques can increase the critical axial load sustainable. This result is unaffected by the presence of edge damage, and can desensitize the shell to edge damage over a larger section of its circumference.
CERAMIC MA TRICES
Analysis of the localized buckling in composite plate structures with applications to determining the strength of corrugated fibreboard Johnson, M.W. and Urbanik, T.J. Journal of Composites Technology and Research Vo111 No 4 (1989) pp 121-128 This paper provides an analysis for the local buckling instability of structural sections with flat plate elements under compression. Preexisting theories for linear isotropic elastic materials were extended to include nonlinear anisotropic elastic materials. Using the developed theory, equations were derived for the stiffness of a single plate element under uniaxial compression. A non-linear finite element analysis was used to calculate the critical buckling load, critical buckling strain and stiffness coefficients for arbitrary sections. This analysis was then applied to fibreboard under compression.
Buckling of thick layered composite plates under inplane moment loading Singh, G., Sadasiva Rap, Y.V.K. and lyengar, N.G.R. Composite Structures Vo113 No 1 (1989) pp 35-48 In this paper a first order shear deformation laminate theory that accounts for the Green Lagrange strain vector is described and its finite element model is developed. This element is used to study the effects of anisotropy, transverse shear modulus, aspect ratio and boundary conditions on buckling behaviour under in plane triangular loading. It is observed that for an angle ply thick plate, maximum load occurs at + / - 15°, whereas for thin plate it occurs at + / - 30°. The authors also report that aspect ratio, boundary conditions and transverse shear significantly affect the buckling load.
Evaluation of the interfacial shear strength, residual clamping stress and coefficient of friction for fiber-reinforced ceramic composites Hsueh, C-H. Acta Metallurgica et Materialia Vol38 No 3 (1990) pp 403-409 The interracial shear strength, residual clamping stress and coefficient of friction at the fibre/matrix interface were evaluated for fibre reinforced ceramic composites, Theoretical analysis of fibre push-out and corresponding experimental results from the SiCRBSN system were used in the analysis. The shear stress was evaluated from the stress at which the debonding initiated after which sliding occurred. With fibres having a Poisson's ratio greater than zero, the characteristics of the nonlinear relationship between the load to push out the fibre and the sample thickness enabled the residual clamping stress, the coefficient of friction and
Axisymmetric stresses in buried thin orthotropic cylindrical shells due to p-wave loading Rap, P.V.M., Singh, V.P. and Upadhyay, P.C. Composite Structures Vo113 No 3 (1989) pp 209-216 This paper is concerned with the study of stresses (axial and hoop) induced in a buried infinite orthotropic cylindrical shell, when it is excited by a p-wave travelling in the surrounding ground. A thin shell theory formulation has been used and only axisymmetric behaviour of the shell has been investigated. The shell is assumed to be perfectly bonded to the surrounding medium of infinite extent. The relative influence of the variation of orthotropy parameters on the stresses in the shell has been studied for different angles of incidence of the p-wave. Results have been obtained for different soil conditions--hard (rocky), medium hard and soft. It is realized that the stresses in the shell can be considerably reduced by adjusting the orthotropy
Comparison between shear deformable and Kirchoff theories for bending, buckling and vibration of antisymmetric angle-ply laminated plates Khdeir, A.A. Composite Structures Vol 13 No 3 (1989) pp 159-172 This paper presents a generalized Levy-type solution in conjunction with the state space concept developed for the bending, buckling and vibration of antisymmetric angle-ply laminated plates. The exact solutions are applicable to rectangular plates with two opposite edges simply supported and the remaining ones subjected to a combination of clamped, simply supported and free boundary conditions. The solutions are obtained for the classical Kirehoff theory and the numerical results are compared with their counterparts using the first order transverse shear deformation theory. The comparisons show that the results obtained within the classical laminated theory can be significantly inaccurate.
C O M P O S I T E S . J U L Y 1990
355