This investigation concerns the mechanical response of binder coated carbon towpreforms and laminates. The main focus is on evaluating and modelling the robustnessof preforms whilst the methodologies developed are also applied to curedlaminates produced using the binder coated preforms. Conventional manufacturingtechniques were altered to address the differences in behaviour due to the presenceof the binder with the development of infusion schedules. These involve lower temperatures,which eliminate the possibility of binder reactivation during processing.Different development versions of the material in the form of an inhomogeneouslyor homogeneously bindered tow were characterised in terms of their mechanical responsein the preform state. It was observed that the inhomogeneously binderedmaterial had higher modulus and strength in both tension in the fibre directionand shear, while the behaviour of the homogeneous preform is significantly morerobust in the transverse to the fibre direction. Laminates produced, using the homogeneouslybindered material, were compared to a reference unbindered laminatesystem, using an aerospace epoxy as a matrix. The out-of-plane properties of thematerial with binder were superior to the reference laminate, whereas in-plane propertieswere similar or inferior. The development of models of the mechanical responsebuilt around continuum damage mechanics models allowed the simulation of the behaviourof preforms under loading. The implementation of these constitutive modelsnecessitated the development of appropriate parameter estimation techniques capableof solving the inverse problem of identifying the values of 27 material constantsthat minimise the error between experimental and modelling results. Two novelmethodologies were developed and compared to a conventional technique followingsimplified laminate analysis. The first method performed a gradient-based errorminimisation and the second uses the Markov Chain Monte Carlo technique. Thegradient-based technique results in a close fit, while this method requires proper definitionof the constraints to yield an appropriate solution set. Markov Chain MonteCarlo yields satisfactory results with the additional advantages of overcoming theill-posedness of the inverse problem without regularisation and providing an outputin the form of multivariate probability distributions that can be used directly instochastic simulations. The material parameters obtained and the correspondingconstitutive models were used in finite element models of the mechanical responseof preforms and laminates. The models were based on the concept of a combinationof shell elements representing sub-laminates and cohesive elements simulatingthe delamination behaviour of interfaces between them. The performance of themodels was evaluated using the case of impact of a spar section for preforms andthree point bending for the laminates. The agreement between experimental andsimulation results was satisfactory. The validated model was used in the contextof a design case study based on a helicopter pitch horn component. The aim wasto use the results of a draping analysis in the finite element model to evaluate theeffects of the assumption of nominal fibre orientations on design and to combinethe results of drape optimisation in respect to fibre shear angle with finite elementanalysis incorporating damage. The results showed that the use of nominal fibreorientation predicts a good performance of the component, whereas the influence ofoptimising draping on the mechanical performance was inferior.
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