Abstract
The objective of this thesis is to investigate the impact behaviour of Glass/PES, Glass/Carbon/PES and Carbon/PES composite tubes by performing analytical and experimental analyses. The aim is to obtain information that will serve as a basis for dealing with the design and testing of these composite tubes. A literature review is presented. This includes the process of manufacture of fibre reinforced composite tubes, impact studies of these materials, test standards, the measurements of elastic material properties and fracture toughness. The process which is employed to manufacture the composite tubes in this investigation is the film stacking hot press moulding technique. The film stacking method has been developed for fabricating continuous fibre reinforced composite tubes and is discussed in detail. Determining the mechanical properties in the tube form of the above composites is considerably more difficult than for isotropic materials. Several mechanical tests are described, together with the application of the laminate theory to determine the orthotropic properties of the composite materials. The basic concepts of fracture mechanics for the linear elastic regime are explained. Fracture mechanics parameters (stress intensity factor and strain energy release rate) for the composite are determined by analytical and experimental methods. A reasonable agreement is obtained and discrepancies between the analytical and the experimental techniques are attributed to the orthotropic properties of the composite. The ACQUIRE software package is used to detect the first three natural frequencies of the glass fibre reinforced PES composite tubes in a free-free condition. The finite element technique is used to determine vibrational frequencies and the dynamic response of these composite tubes. A review of test methods illustrates the importance of developing a test technique for determining the impact force - time and acceleration - time responses of the glass fibre reinforced PES composite tubes. Also two methods to calculate the damping factor of the composite material are described.