Physics-informed modeling of nonlinear dynamics in graphene origami reinforced FG porous copper beams in fluid environments

This study examines the nonlinear vibration and postbuckling behavior of functionally graded porous copper beams reinforced with graphene origami (GOri) metamaterials, partially immersed in fluid. The analysis focuses on how porosity characteristics and negative Poisson’s ratio (NPR) influence nonlinear dynamic performance in fluid environments. Material properties are predicted using a physics-informed genetic programming model integrated with micromechanics principles. Structural behavior is modeled through first-order shear deformation theory and von Kármán nonlinearity, with governing equations solved via the generalized differential quadrature method. Fluid-structure interaction (FSI) effects are incorporated using a velocity potential approach and Bernouilli’s equation. Results show that symmetric porosity distribution enhances nonlinear vibration and postbuckling resistance compared to uniform and asymmetric patterns. Increasing porosity reduces stiffness and load carrying capacity, while GOri reinforcement significantly improves both vibrational frequencies and postbuckling stability. Fluid immersion dampens the nonlinear vibrational frequencies but enhances resistance under compressive loads. These findings provide insights for designing lightweight, high strength metamaterial structures for aerospace, marine and advanced engineering applications.