An investigation has been made into the possibility of using composite materials for intermediate range structural designs. That is, designs between the small and relatively low stressed requirements such as furniture where the quantity of G.R.P. does not dominate the cost and higher requirements such as in aircraft and ships where the cost is acceptable. As an example of this level, a joint investigation with industry was made into the possibilities of using composites for the quantity manufacture of international shipping containers. The only acceptable material for such a large structure (weighing 2 tons) is Glass Reinforced Polyester and while the whole container was considered this thesis concentrates on the design and approval of the floor structure. The properties of a variety of G.R.P. glass forms and polyesters have been measured from material tests and statistical safe values derived. As stiffness is of great importance both static and dynamic elastic modulus have been measured. Floor panels have been designed and tested and these show that to meet both structural and manufacturing requirements the glass form will be a mixture including, woven rovings, uniaxial fibres, chopped strand mat and possibly a low density filler. The use of adhesive bonding as a main method of jointing has led to a programme of tests including the effect of joint geometry. These methods are to be preferred to mechanical fasteners even when joints are made to metals. It was found to be possible to design a container floor to meet the International Standard at Q structure weight which is better than existing containers. The cost of the glass fibre and polyester made the container cost appreciably higher than the price of conventional containers.
|Date of Award||1981|