We have investigated the effect of the laminating structure of glass cloth on the elastic anisotroly of FRP in which plain-woven glass cloth is embedded. The relationship between the manner of piling up glass cloth and the elastic anisotropy of FRP has been analyzed by using a mechanical model. The major results of our research are:
A)The elastic anisotropy of FRP may disappear if equal numbers of sheets of cloth (a) (plainweave glass cloth) and cloth (b) (the same as cloth (a) but rotated 45°) are embedded.
B) For FRP in which many sheets of glass cloth oriented parallel with one another are embedded, Young's modulus gets a maximum value in the directions of warp and weft of the cloth and declines to a minimum in the center direction.
C) Placing cloth (b) on top of cloth (a) reduces Young's modulus in the yarn direction of cloth (a) in FRP, if sheets of cloth (a) and (b) to the number n each (2n sheets in all) are embedded, Young's modulus declines to 80% of that where 2n sheets of cloth (a) only are embedded.