A LOGIC-BASED MECHANICAL SYSTEM CONSTRAINT MODEL

This paper: (1) classifies design constraints of mechanical systems fr om a multi-disciplinary, concurrent engineering point of view from thr ee 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 fo r mechanical systems using predicates. Axioms and atomic formulas of m echanical assemblies are developed. Two frequently used assembly relat ionships - fit and against - are defined and used to explain the assem bly definition axiom of a piston assembly of an engine model. Such a g eometry constraint modeling method builds a basis for design change pr opagation and change management.