Modelling effect of layer shift on properties of woven fabric composites

Abstract

The eVect of layer shift on the mechanical behaviour of woven fabric laminates has been examined using nite element analysis. Simpli ed two-dimensional generalised plain strain models have been developed for laminates in which the neighbouring layers are in phase (no layer shift), out of phase, or 'staggered' with respect to each other. Values for moduli and energy release rates associated with matrix crack formation are presented both for woven fabric laminates, as functions of layer shift and laminate thickness, and for a nominally equivalent crossply (non-woven) laminate. It is shown that at the same level of applied mechanical strain, the values of energy release rate for crack formation are similar for crossply and woven laminates in which the cracking occurs away from the crimp region, provided that there is no signi cant bending. When crack formation is adjacent to the crimp region, the associated energy release rates are higher.

Industrial looks at ways of manufacturing defects of fiber reinforced polymer composites.

“…Schematic edge views of damage morphologies in two layer PW GFRP laminates, indicating different relative layer positions: a in phase; b 180° out of phase; and c at some intermediate or staggered phase difference (loading left to right for each figure)[42] …”

“…Applications of using multiple fabric layup are also limited in this process. This process also has the tendency to make the fiber reach or exceed the shear lock limit[27] [28].The effect of layer shift on the mechanical behavior of woven fabric laminates has been examined using finite element analysis by Page[42]. Simplified twodimensional generalized plain strain models have been developed for laminates in which the neighboring layers are in phase (no layer shift), out of phase, or 'staggered' with respect to each other (Figure 12).…”