A Knowledge-based System for Liquid Retaining Structure Design with Blackboard Architecture

Owing to the high degree of vulnerability of liquid retaining structures to corrosion problem, there are stringent requirements in its design against cracking. In this paper, a prototype knowledge-based system is developed and implemented for the design of liquid retaining structures based on the blackboard architecture. A commercially available expert system shell VISUAL RULE STUDIO working as an ActiveX Designer under the VISUAL BASIC programming environment is employed. Hybrid knowledge representation approach with production rules and procedural methods under object-oriented programming are used to represent engineering heuristics and design knowledge of this domain. It is demonstrated that the blackboard architecture is capable of integrating different knowledge together in an effective manner. The system is tailored to give advice to users regarding preliminary design, loading specification and optimized configuration selection of this type of structure. An example application is given to illustrate the capabilities of the prototype system in transferring knowledge on liquid retaining structure to novice engineers. Introduction By its very nature, the design of a building structure is a complicated process which integrates both design knowledge and analytical skills. It is not easy to incorporate the available empirical and heuristic knowledge into a numerical model for decision making. It is even more difficult for liquid retaining structure design due to the high degree of vulnerability of these specialized structures to corrosion problems. There are stringent requirements against cracking and a considerable amount of heuristic inferences, design code requirements, and expert experience are involved, in accordance to the particular configuration, support conditions and loading requirements. However, up till the present, algorithmic models are often used to simulate structural design processes, resulting in large constraints in model uses as well as a large gap between model developers and practitioners. Most algorithmic models are not user-friendly enough and lack sufficient support to novice users and knowledge transfers in appropriate model application. Yet, there is a real necessity to transfer this expertise knowledge to novice engineers. Moreover, design can be considered an open-ended problem to select the optimal solution, via minimization of either the total cost or weight of the entire structure. There are often several alternatives that can satisfy all the specified constraints. In this point of view, structural design can be represented by a cooperative constraint-satisfying process with several knowledge sources. In order to address such an ill-structured problem, skillful as well as iterative knowledge manipulation and learning process are entailed for selection of the most appropriate design parameters and successful implementation of computer-aided design. This is the Pre-Published Version.