This work is an attempt to provide simple formulae that can predict the initial behaviour of the most commonly used fabric, namely the plain weave. To achieve this, a simple zigzag shape 'saw-tooth model' was adopted to describe the yarn configuration in the weave structure. An energy method, using Castigliano's theorem, was then employed to derive closed form solutions which relate the yarn parameters and the fabric moduli under either tensile or bending strains. To examine the theory, series of tests were carried out on different plain weave structures and the theoretically calculated results were compared with the actual fabric behaviour. The outcome of the study showed that, when the yarn and fabric parameters are accurately defined, it is possible to obtain a reasonable estimate of the above mentioned fabric properties using the formulae derived in the theoretical analysis. The results and discussion also showed that the initial deformation of some plain weave constructions may produce extension and/or compression strain energies that cannot be ignored in estimating the fabric behaviour with reasonable accuracy
