In this study, a functional and behavioral representation model for collaboration in product development is developed to represent assembly-related product knowledge, including its geometry, spatial relationships, function and behavior, which will be used to create a knowledge representation scheme to capture, store, and retrieve product knowledge. In this model, the function, behavior and artifact information is interrelated based on assembly associations. Functional and behavioral inputs and outputs are defined based on the spatial relationships in the assembly, as well as on the geometry of the product. The functional associations among artifacts define the "Behavior Model" with engineering formulas and physical rules. "Behavior Models" then define the behavior of the artifact. Behavior has four different forms for different phases in life cycle: (1) Intended Behavior in the conceptual design phase, (2) Estimated Behavior in the design phase, (3) Observed Behavior in the operation stage, and (4) Evaluated Behavior in the design and operation phases. When an unintended event (behavior) occurs, an additional function can be added to eliminate that effect. As a result, the functional and behavioral model is updated dynamically.