The evolution of transverse stresses in hybrid composites under hygrothermal loading

This paper presents a hygrothermal analysis of the hybrid composites under the effect of the cyclic environmental conditions in order to determine the transient transverse stresses of the [θ/−θ]S stacking sequences. Hybrid composite is used to consider an appropriate isolation against the cyclic environmental conditions, as well as the reduction of the hygrothermal transverse stresses at both edges of the plate. To reach this aim, we used initially, the computer code W8gain developed by Springer for the determination of the moisture concentration at the end of each cycle. Thereafter, a computer code is developed to compute the hygrothermal transient stresses with implicit variation of temperature and moisture concentration after each cycle. To reduce the transverse stresses, some cases of hybrid composites are proposed. For each case, the thickness of each material constituting the hybrid plate (T300/5208 or AS/3501-5) is gradually varied, but the total thickness of our plate remains unchanged. This thickness variation enables us to find an appropriate hybrid plate which predicts an optimal reduction of hygrothermal transverse stresses; consequently an increase in durability of our hybrid plate.

Research highlights
► Hybrid composite is exposed to the effect of the cyclic environmental conditions.
► Stacking sequences [θ/−θ]S are used in order to find the best mechanical characteristics.
► A computer code is developed to compute the hygrothermal transient stresses.
► The thickness variation enables us to find an appropriate hybrid plate.