Size-dependent effects in bi-material and functionally graded layers under surface excitation loading

This thesis investigates the mechanical behavior of multilayered andfunctionally graded materials (FGMs) at the nanoscale, emphasizing the significantinfluence of couple stress and surface stress. The analysis focuses on stress distributionand deformation under surface loading and flat-end indentation. Four models werecompared to assess the effects of each stress component. The governing equations wereformulated using the Hankel transform and expressed in stiffness matrix form tofacilitate numerical computation. For indentation problems, the collocation method wasapplied to discretize the system. In the FGM analysis, three gradation profiles Power-law, Exponential, and Sigmoidal were evaluated to examine their influence onmechanical response. The findings provide insight into size-dependent behavior andoffer a framework for designing advanced material systems with enhanced mechanicalperformance at the nanoscale.