Investigating the Sealing Performance of D-Section High-Elastic Seals: A Parametric Study on Material Formulation and Geometric Design

High-elastic seals with a D-shaped cross-section are extensively used in engineering assemblies, yet the quantitative relationship between their sealing capability and the governing material and dimensional factors remains insufficiently understood. Clarifying these factors is of considerable practical significance, as it supports reliable design and broadens the applicability of such components. In this work, a planar finite element model discretized with a highly refined mesh is established, in which the D-section seal is idealized as a Mooney–Rivlin hyperelastic material. The evolution of the von Mises stress field throughout the seal body during the downward travel of the indenter is adopted as the evaluation metric, permitting a quantitative assessment of sealing performance with respect to both material formulation and cross-sectional dimensions. Relative to the unfilled matrix, the mean peak stresses of the filled NR, VMQ, NBR and EPDM compounds are amplified by factors of 2.09, 2.22, 1.33 and 1.71, respectively; their carbon-fiber-reinforced counterparts exhibit a further increase to 5.46, 2.42, 3.13 and 9.59 times. A sensitivity hierarchy of the geometric variables is subsequently established, ranked in descending order of influence as the crest arc radius R1, the rigid indenter radius R0, the seal thickness a, the transition fillet radius R2, the bond length L and the clearance to the side wall S. The trends identified here elucidate the underlying deformation and contact mechanisms, thereby providing a quantitative foundation for the further application-specific design of D-section rubber seals.