A logic-based mechanical system constraint model

This paper: (1) classifies design constraints of mechanical systems from a multi-disciplinary, concurrent engineering point of view from three orthogonal bases: application, object, and expression, (2) presents some initial developments in extending data models to include design constraints, formally defining entity relationships using first order predicate logic, and modeling assembly related geometry constraints for mechanical systems using predicates. Axioms and atomic formulas of mechanical assemblies are developed. Two frequently used assembly relationships-fit and against-are defined and used to explain the assembly definition axiom of a piston assembly of an engine model. Such a geometry constraint modeling method builds a basis for design change propagation and change management.