An Extended Thickness-Dependent Moisture Absorption Model for Unidirectional Carbon/Epoxy Composites.

Area of Science:

• Materials Science
• Polymer Science
• Composite Materials

Background:

• Non-Fickian moisture absorption in composites requires lengthy experiments to reach saturation.
• Characterizing moisture absorption behavior is essential for predicting material performance and durability.
• AS4/8552 carbon/epoxy composites are widely used in structural applications.

Purpose of the Study:

• To characterize the non-Fickian moisture absorption behavior of AS4/8552 carbon/epoxy composites.
• To establish thickness-dependent models for non-Fickian parameters.
• To minimize experimental time and cost associated with moisture absorption testing.

Main Methods:

• Specimens of 4, 8, and 16 plies were prepared and immersed in distilled water at 60 °C.
• A thickness-dependent model was used to characterize non-Fickian parameters: ϕ, α, and t.
• Power law fitting and Weibull distribution analysis were employed to assess the relationships.

Main Results:

• All three non-Fickian parameters (ϕ, α, t) were successfully fitted using a power law model.
• The Weibull distribution indicated a 62% probability of non-Fickian absorption influenced by ϕ and α at normalized thickness 2-3.
• An 82% probability of non-Fickian absorption influenced by t was observed at a normalized thickness of 6.

Conclusions:

• Thickness-dependent models can effectively characterize non-Fickian moisture absorption in AS4/8552 composites.
• The Weibull distribution is a viable tool for assessing non-Fickian moisture absorption based on material thickness.
• This approach offers a pathway to reduce experimental duration and costs in composite material characterization.