<p>Systems Engineering addresses the design and management of complex systems, in which requirements and change impact analysis play a critical role. Although SysML, widely used in Model-Based Systems Engineering, supports requirements specification and traceability, it lacks formal semantics, preventing automated inference and rigorous impact propagation for advanced analysis. Leveraging Semantic Web technologies enables the formalization of SysML models and the application of reasoning mechanisms for requirements and change impact analysis. This paper proposes an approach that integrates SysML with OWL ontologies to support semantically driven analysis during system design. The main contributions include an ontological representation of requirements, an automatic transformation of SysML requirements diagrams and their trace relationships into OWL, semantic queries for requirements analysis, and semantic rules and queries for change impact formalization and analysis. The proposed approach is supported by a dedicated tool and is validated through a case study demonstrating its effectiveness in generating OWL ontologies from SysML requirement diagrams, detecting requirement inconsistencies, supporting verification and validation activities, and analyzing change impact.</p>