Abstract
Many classes of mechanical systems must now bedesigned with members possessing high stiffness-toweight ratios and high strength-to-weight ratios inorder to achieve superior performance characteristics.One of the philosophies proposed for addressing theseclasses of problems requires the articulating membersto be fabricated with modern composite materials.While these materials enable high-strength, high-stiffness and low-mass members to be fabricated, the properties of these polymeric materials are adversely affected by elevated temperatures and also moistureabsorption. The subject of this paper is the development of a methodology for predicting the dynamic hygrothermoelastic response of machine systems fabricatedwith these advanced materials. This methodology isbased on a variational theorem which provides the basisfor a finite element formulation. An illustrativeexample serves to demonstrate some preliminary work onpredicting the response of a four-bar linkage fabricated with polymeric composite links simultaneouslysubjected to both mechanical and hygrothermal loadings.