Pultruded, fibre reinforced, polymeric composites are now being used in a wide range of structural engineering applications, due to their high strength to weight ratios and resistance to environmental conditions. However, such materials posses a relatively low shear modulus in relation to their axial and flexural moduli. This can result in shear deformation constituting a significant proportion of the total deformation and a reduction in buckling loads for various modes of instability. An experimental and theoretical study of the influence of shear deformation on the flexural and torsional stiffnesses and various modes of instability of pultruded polymeric bars of open cross-section is therefore presented. Theories for the bending and warping torsional response of pultruded, fibre reinforced polymeric bars of open cross-section, excluding and including the influence of shear deformation, are presented. Full section bending mechanical properties of several pultruded beams are determined using a static testing apparatus and a wide variety of span configurations. Full section warping torsional mechanical properties of several pultruded bars are determined using a new testing apparatus, capable of applying a torque to any cross-section along a bar, whilst maintaining the bars lateral position. Theories for the flexural, torsional and lateral instability of pultruded, fibre reinforced polymeric bars of open cross-section, excluding and including the influence of shear deformation, are developed and presented. Parametric studies of the influence of shear deformation in the flexural, torsional and lateral instability of various pultruded bars of open cross-section are also presented. The experimental and theoretical studies indicate that shear deformation reduces significantly the non-uniform bending stiffness of pultruded polymeric bars, but that its influence on the non-uniform and restrained warping torsional stiffness is practically negligible. Shear deformation has also been found to result in a significant reduction in flexural, torsional and coupled flexural-torsional or lateral buckling loads.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:324099 |
| Date | January 1999 |
| Creators | Al-Ubaidi, Haitham |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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