Global sensitivity analysis of MGT thermo-magneto-microstretch media with reference-scaled thermal conductivity

Khan M. A., Ziadi K., Ben Moussa S., Jahangir A., Alzahrani A. Y. A., YAYLACI M.

INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER, cilt.180, 2026 (SCI-Expanded, Scopus)

Özet

This paper presents a theoretical and numerical investigation of the coupled thermo-magneto-elastic behavior of a microstretch thermoelastic half-space subjected to mechanical and magnetic loading within the Moore-Gibson-Thompson (MGT) theory of thermoelasticity. The thermal conductivity is modeled by the referencetemperature family kappa = kappa 0(1 - alpha kappa T0), where alpha kappa is a material parameter and T0 is the reference temperature. It is emphasized at the outset that this family assigns a constant conductivity to each realization when T0 and alpha kappa are fixed; the model therefore belongs to the class of constant-property families rather than to evolving-temperature closures such as kappa(theta) = kappa 0(1 + K1 theta). The Kirchhoff transformation consequently reduces to the exact linear rescaling psi = (1 - alpha kappa T0)theta, which introduces no thermal nonlinearity and does not alter the underlying material coupling constants. The governing system constitutive relations, the MGT heat-conduction equation, dimensionless field variables, normal-mode expansion, and associated boundary conditions is derived in full. The normal-mode solution is validated against four independent limiting cases: (i) H0 -> 0 (non-magnetic thermomicrostretch), (ii) alpha kappa -> 0 (constant-conductivity MGT), (iii) suppression of microstretch (MGT thermoelastic half-space), and (iv) comparison with a published MGT half-space solution. A global sensitivity analysis (GSA) based on Sobol first- and total-order indices, the Morris elementary-effect method, and partial rank correlation coefficients (PRCC) is then performed on a parameter set drawn directly from the governing equations: X = [P, H0, alpha kappa, tau 0, k, lambda 0, alpha 0](T). The results show that alpha kappa dominates the response of nearly all quantities of interest, while the micropolar coupling k & oline; and microstretch coupling lambda 0 exert secondary but non-negligible influence. The magnetic parameter H0 and the microstretch modulus alpha 0 have small total-order indices. The GSA is consistent with the mathematical structure of the formulation and identifies the parameters that most strongly control nearsurface field amplification in MGT thermo-magneto-microstretch media.