Intelligent Support to Post-processing Phase of Engineering Analysis

MARINA NOVAK & BOJAN DOLŠAK Laboratory for Intelligent CAD Systems, Faculty of Mechanical Engineering

University of Maribor Smetanova 17, SI-2000 Maribor, SLOVENIA

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Abstract: - The results of engineering analysis are often used as basic parameters for design optimisation process. However, the existing commercial software for engineering analyses still fails to provide adequate expert advice in post-processing phase of the analysis. Thus, the selection of appropriate design steps to improve the structure still depends mostly on the designer's knowledge and experience. A prototype of intelligent consultative system for supporting design decisions considering the results of a prior stress/strain or thermal analysis is presented in this paper. Intelligent system provides a list of redesign recommendations which should be considered to optimise a certain critical area within the structure. Key-Words: - computer aided design, engineering analysis, design optimisation, redesign, decision support,

knowledge-based systems, PROPOSE 1 Introduction For many years various Computer Aided Design (CAD) applications are indispensable in design process. The skilled usage of CAD tools increases the designers’ effectiveness and their capability to solve complex design problems. CAD systems cover different design activities, like modelling, kinematics, simulations, structural analysis or just drawing technical documentation. In spite of all that, they do not support designer in more creative parts of design process that involve complex reasoning [1], as for example when possible design solutions need to be evaluated.

To overcome this bottleneck, “intelligent behaviour” needs to be added to existing CAD systems. Knowledge-based Engineering (KBE), or Knowledge Aided Engineering (KAE), presents the link between Computer Aided Engineering (CAE) tools and methods of Artificial Intelligence (AI). KAE was born in the aircraft [2] and automotive industries [3] and has been applied over several years, but mostly for specific products.

Despite all this, designer lacking in experience still needs advice to be able to make the right decisions within design process and consequently to design optimal structures. The idea behind present research in this field is to apply intelligent advisory computer systems to provide decision support to design activity. In the paper, a prototype of the intelligent consultative computer system to support one of the crucial steps in design is presented. 2 Engineering Analysis Optimal design performed at the first attempt is rare in engineering. The purpose of engineering analysis using, for example, Finite Element Analysis (FEA), in the

design process is to simulate and verify the conditions in the structure, as they will appear during its operational life. If the structure does not satisfy given criteria, it needs to be improved by applying certain optimisation steps, such as design changes, use of another material, etc. A lot of knowledge and experience is needed to be able to understand the results of the analysis and to choose the appropriate optimisation measures. In spite of rapid progress in the field of graphics, workstations and corresponding software, the existing computer tools for post-processing fail to provide advice about further optimisation steps.

KBE techniques linked to FEA have been available over twenty years to teach, advice and automate the pre-processing stage, mainly involving automatic mesh generation. On the other hand, there are not so many reports about AI applications to the post-processing phase and to the consequent design modification and optimisation [4-7].

In practice, young engineers are capable to make a model of a design using a CAD system. When they want to verify their design, they usually manage to perform the analysis and obtain useful graphical presentations of the results from which critical areas can be located. However, they know neither how to perform design changes nor what to change to improve the design.

The list of possible redesign actions is a case-by-case solution of some quite complicated problems that require knowledge about the principles of mechanics, structures and materials technology. The experiences gained by many design iterations are of crucial importance. As a rule, there are several redesign steps possible for design improvement. The selection of one or more redesign steps that should be performed in a given case depends on the individual requirements of the certain problem.

Proceedings of the 4th WSEAS/IASME Int. Conf. on System Science and Simulation in Engineering, Tenerife, Spain, December 16-18, 2005 (pp17-20)