Thermoelastic diffusive plate with microconcentrations embedded between elastic layers

Classical coupled thermoelastic-diffusion theories adequately describe the interaction of thermal, mechanical, and mass-transport fields in homogeneous media, yet they fail to capture microstructural concentration effects that govern the response of layered systems in which a diffusive medium is confined between elastic constituents. This study addresses that gap by analyzing the thermomechanical behavior of a three-layer composite in which a thermoelastic plate, incorporating both mass diffusion and microscopic concentration effects, is embedded between two identical elastic layers, with the upper layer subjected to a constant mechanical load. The principal novelty lies in explicitly resolving microstructural concentration variations within the thermo-diffusive plate, thereby extending the analysis beyond conventional coupled thermoelastic-diffusion formulations. The governing equations are solved analytically using potential function methods together with two-dimensional modal expansion, yielding closed-form expressions for displacement, stress, temperature, concentration, and mass diffusion flux. The results show that the relative thickness exerts a decisive influence on the thermoelastic-diffusive coupling: normal stress retains a consistent oscillatory character across all configurations, whereas tangential stress, temperature, and concentration profiles are strongly modulated by the plate thickness. Diffusion phenomena are found to be most pronounced when the thermo-diffusive and elastic layers are of comparable thickness.