THERMAL RESIDUAL STRESSES IN ONE-DIRECTIONAL FUNCTIONALLY GRADED PLATES SUBJECTED TO IN-PLANE HEAT FLUX


Bagci M. D. , APALAK M. K.

NUMERICAL HEAT TRANSFER PART A-APPLICATIONS, cilt.60, ss.50-83, 2011 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 60 Konu: 1
  • Basım Tarihi: 2011
  • Doi Numarası: 10.1080/10407782.2011.588554
  • Dergi Adı: NUMERICAL HEAT TRANSFER PART A-APPLICATIONS
  • Sayfa Sayıları: ss.50-83

Özet

This study carries out the transient thermal residual stress analyses of functionally graded clamped plates for different in-plane material compositions and in-plane heat fluxes. The heat conduction and Navier equations representing the two-dimensional thermoelastic problem were discretized using the finite-difference method, and the set of linear equations were solved using the pseudo singular value method. Both in-plane temperature distributions and the heat transfer period were affected considerably by the compositional gradient. The type of in-plane heat flux had a minor effect on the temperature profile, but on the heat transfer period. The high stress levels appeared in the ceramic-rich regions. The normal and equivalent stresses exhibited a sharp change in the plates with ceramic-rich as well as metal-rich compositions, and the concentrated on a narrow ceramic layer. A smooth stress variation was achieved through the graded region with a balanced composition of ceramic and metal-phases, and the stress discontinuities disappeared. The in-plane shear stress was negligible. The equivalent stress exhibited a linear temporal variation for both constant and sinusoidal heat fluxes, but a nonlinear variation for the exponential heat flux. In case the heat flux is applied along the metal edge (metal-to-ceramic plate) instead of the ceramic edge, the displacement and stress components exhibited similar distributions to those of a ceramic-to-metal plate but in the opposite direction. As a result, the distribution of in-plane material composition affects only normal stress distributions, whereas the peak stress levels occur in the ceramic-rich regions. Since the normal stresses concentrate along a narrow ceramic layer for ceramic-rich or metal-rich compositions, a balanced in-plane material composition distribution of ceramic and metal would be useful to avoid probable local ceramic fracture or damage.