  Functionally graded porous plates have been validated as remarkable
lightweight structures with excellent mechanical characteristics and numerous
applications. With inspiration from the high strength-to-volume ratio of triply
periodic minimal surface (TPMS) structures, a new model of porous plates, which
is called a functionally graded TPMS (FG-TPMS) plate, is investigated in this
paper. Three TPMS architectures including Primitive (P), Gyroid (G), and
wrapped package-graph (IWP) with different graded functions are presented. To
predict the mechanical responses, a new fitting technique based on a two-phase
piece-wise function is employed to evaluate the effective moduli of TPMS
structures, including elastic modulus, shear modulus, and bulk modulus. In
addition, this function corresponds to the cellular structure formulation in
the context of relative density. The separated phases of the function are
divided by the different deformation behaviors. Furthermore, another crucial
mechanical property of porous structure, i.e, Poisson's ratio, is also achieved
by a similar fitting technique. To verify the mechanical characteristics of the
FG-TPMS plate, the generalized displacement field is modeled by a seventh-order
shear deformation theory (SeSDT) and isogeometric analysis (IGA). Numerical
examples regarding static, buckling, and free vibration analyses of FG-TPMS
plates are illustrated to confirm the reliability and accuracy of the proposed
approach. Consequently, these FG-TPMS structures can provide much higher
stiffness than the same-weight isotropic plate. The greater stiffness-to-weight
ratio of these porous plates compared to the full-weight isotropic ones should
be considered the most remarkable feature. Thus, these complex porous
structures have numerous practical applications because of these high ratios
and their fabrication ability through additive manufacturing (AM) technology.
