A mixture theory approach for the constitutive modeling of coupled hygro-thermo-elastic phenomena in fiber-reinforced polymeric composite materials

Abstract

Several theoretical and experimental investigations have highlighted the vulnerability of polymeric fiber-reinforced composite materials to severe hygro-thermal environments. Traditionally, single constituent theories have been employed to model the constitutive response of idealized polymeric composite materials in hygro-thermal environments. Typically, these theories do not incorporate moisture as a distinct constituent in an explicit sense, and the moisture and temperature effects are treated as being uncoupled from the mechanical response of the composite material. The deficiencies of traditional techniques in modeling the hygro-thermo-elastic response of polymeric composites are addressed in this paper by treating the moisture-composite aggregate within the context of Mixture Theory. This approach not only permits the explicit incorporation of moisture and its effects, but it also allows the possibility of deriving constitutive equations to model the coupled hygro-thermo-elastic response of idealized fiber-reinforced composite materials undergoing small deformations. An illustrative example is presented in order to highlight the significant role of the fibers in modifying the hygro-thermo-elastic characteristics of the overall composite material. The authors believe that this is the first paper which rigorously treats the hygro-thermo-elastic behavior of polymeric composites in the context of Mixture Theory, and it is anticipated that this approach will have significant relevance in solving practical problems in defense, aerospace and manufacturing environments, where significant variations in moisture and temperature conditions are routinely encountered.