A knowledge-based system for materials selection in mechanical engineering design Abstract This paper studies various work on the development of computerized material selection system. The importance of Knowledge-based system (KBS) in the context of concurrent engineering is explained. The study of KBS in material selection in an engineering design process is described. The development in materials databases, which sometimes serve as material selection packages, is also discussed. The use of KBS in material selection and the application in the domain of polymeric-based composite are chosen as typical examples. 2001 Published by Elsevier Science Ltd.50232

1.0 Introduction

Materials selection is a task normally carried out by design and materials engineers. Gutteridge and Water- man [1] described the aim of materials selection as the identification of materials, which after appropriate manufacturing operations, will have the dimensions, shape and properties necessary for the product or component to demonstrate its required function at the lowest cost. For the purpose of material selection, thousands of data would be needed to characterize all the grades of materials. Many selection systems are available to help design engineers to choose the most suitable materials. At the most basic level, design engineers could use tables of material properties in data books. However, data sheets are incomplete and once published, they are difficult to update. Dodd and Fairfull [2] described how information about engineering materials, can be pided into two main categories, i.e. data and knowledge. Data is defined as the results of measurements, whereas knowledge represents the connections between items of data, the source of this knowledge, which contributes to an understanding of the results. Both the computerized database and the KBS of material selection will be described in the following sections.

2.0 The material database for materials selection

2.1. Supporting data and rigorous logic for the hypothesis and obseruation

In recent years, attention is being made to the use of computer systems to store and process data regarding the properties of materials. It enables the designers to achieve large capacity and rapid retrieval from a computer database to provide easy access to the materials data. According to Prasad [3], materials are the common elements enumerating parts in a product realization process. Nowadays, design engineers normally rely on the materials that they are familiar with. However, when design requirements exceed the constraints of such materials or exceed the constraints on material properties, concurrent engineering teams must consider alternative materials. With direct online access to a materials database, the concurrent engineering teams could select materials that are lighter, stronger and lower in cost. Assuming that the impact of such substitutions can be analyzed or simulated, the teams could easily make an optimum selection of materials for the available processes, conserve materials for each process and thus, reduce material waste.

White [4] emphasized the importance of computer aided materials selection as books have several drawbacks as they are often outdated before reaching the bookshelves. It is very difficult to index them to find answers or to sort data in the manner of your choice.

A computerized system, which provides access to materials data, is not necessarily a materials selection system, although access to data is essential to facilitate selection.

2.2. Critical review

This section reviews the development of computerized materials databases that enabled designers to select the materials in mechanical engineering design application. The development of material databases has been reported by Harmer [5] , Breuer et al [6-10], Baur [11-12] , Michaeli [13] , Ashby [14-15] and Cebon and Ashby [16-17] .

Harmer [5] reported that various database systems have been developed for plastics, elastomers and rubbers such as the Cambridge Materials Selector (CMS) , CAMPUS, Selector II, Plaspec, CenBASE/Materials, Mat. DB, Plastics Design Library .Engineered Materials Abstracts, FUNDUS, Prospector Plus, Polymat, SPAO, Pro-Concept, Explorer, Platt’s Polymerscan, Standards Infodisk, Pira Abstracts, Packaging Science and Technology Abstracts, Chem-Intell and Weldasearch.