The model of concurrent configuration design and the architecture of Concurrent Configuration Design Advisor (CCDA) are considered. The CCDA is developed as an open dynamic expert system of interacting agents. In the context of this article a configuration problem is defined as a decision-making procedure performed by concurrent processes (agents). The analysis of concurrent and sequential activities in this system is based on structural transformations (in the form of graph grammars) that permits the definition of correct criteria for data integrity and the consistency of configured project data model, and any dynamic changes in the project to be modeled conveniently. This approach also makes it possible to handle complex hierarchial data structures of real configured objects and to model communication and synchronization of decision making in a distributed expert system in a common formalism. The system to be configured is decomposed into structured objects, called fragments. The proposed model consists of three types of agents. D-agents are those capable of the object configuration design within the constraints on their attributes. To cope with agents' coordination, objects' consistency and data integrity problems, a special type of agent, facilitator or F-agent, is introduced. Finally, project assistants or A-agents are responsible for the user interface at the stage of object model definition. The discussion is illustrated with examples from the application domain of flexible manufacturing systems. Experimental results, current and future work on the expert system implementation are considered.