Contamination-sensitive convergence and grid-independence analysis for GDQM-based vibration modeling of rotating porous filtration plates

A rigorous vibration framework is developed for a porous filter which is modeled as a rotating annular porous plate operating in contaminant-rich environments, where progressive deposition alters both inertia and structural rigidity. Unlike conventional approaches that treat fouling solely as an added mass, the present formulation introduces a coupled mass–stiffness modification mechanism to capture the dual physical impact of pollutant infiltration within the porous architecture. The structural kinematics are described based on a sinusoidal higher-order theory, enabling a higher-order representation of transverse shear deformation through the plate thickness. Rotational effects are incorporated through a consistent energy-based inclusion of centrifugal pre-stress, ensuring realistic modeling under high-speed conditions. The governing equations, enriched by contamination-induced modifications in inertia, stiffness, and pre-stress fields, are solved via the generalized differential quadrature method. Numerical investigations demonstrate that the dynamic response exhibits pronounced sensitivity to stiffness degradation, strongly modulated by geometric parameters such as thickness, thereby revealing a geometry-dependent environmental susceptibility. Furthermore, centrifugal stiffening at elevated rotational speeds is shown to partially obscure the influence of internal porous architecture. Importantly, the interaction between accumulated mass and stiffness variation is found to be intrinsically non-additive, highlighting a critical limitation in traditional vibration-based diagnostic strategies. These findings provide new insights into the design and condition monitoring of rotating porous filtration systems under realistic operating conditions.