A complete rate-dependent constitutive model of thermo-elasto-diffusive coupling and its application in structural dynamic responses analysis of multi-layered laminated sandwich composites subjected to axisymmetric heat and chemical shock loadings

Metal solids or composites often work in high-temperature environments, which raise higher requirements for their mechanical strength design, even for oxygen diffusion. This motivates great interests on the constitutive modeling of thermo-elasto-diffusive coupling behavior from scholars and engineers, of which the most representative one is called rate-dependent thermoelastic diffusion theory associated with temperature and molar concentration rates. However, in ultrafast heating condition, the increasingly prominent relaxation effects in elastic deformation field are still not considered in this theoretical formulation. To deal with the deficiency, present study aims to develop a complete rate-dependent constitutive model of thermoelastic diffusion by fully considering temperature rate, strain rate, and chemical potential rate. New constitutive relations and governing equations are derived within the extended thermodynamics framework. To illustrate its application values, the newly developed model is applied to investigate transient thermo-elasto-diffusive dynamic responses of multi-layered laminated sandwich composites considering perfect interfacial conditions and material constants ratios by a semi-analytical technique via Laplace transformation. The achieved results reveal that properly selecting relaxation time parameters and material constants ratios of such structure will eliminate discontinuity of deformation, adjust thermal/diffusive waves propagation, realize displacement control, regulate heat/diffusion isolation, and improve harmful stress isolation induced by heat or oxygen diffusion.