Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

A computer knowledge based system for selecting materials, treatments and surface coatings

PRECEPT is a knowledge based computer system, which is being constructed to assist the engineering designer in the selection of materials, treatments and surface coatings to satisfy the design and service requirements of a component.

There is an industrial need for this type of selection methodology that provides support for the simultaneous engineering approach to design.

Reasons for developing the system include:
support for simultaneous engineering teams;
use of a more rigorous selection methodology;
more alternatives evaluated at an early stage in the design;
faster evaluation of alternative solutions;
efficient use of scarce materials specialists.

Benefits include:
improved products to meet design requirements;
lower costs from improved access to information and reduced design changes after product launch;
more options considered with positive elimination of alternatives;
a means to record, store and communicate knowledge.

The system contains a methodology that has been developed in response to the need to provide a wider view of alternative solutions and for more accurate evaluations of candidate combinations earlier in the design process. (A combination is a single material, in a particular condition, with none, one or more treatments or processes applied to it).

The essence of the system is to match the requirements of the application (what is needed) with the properties available from suitable combinations of materials, coatings and treatments (what is possible). The user's requirements, such as lifetime, operating environment and load, are converted by the knowledge base into criteria that can be used to select the candidate combinations.

The knowledge base in PRECEPT contains 3 modules covering fatigue, wear and corrosion. The knowledge contained within each module is a combination of theoretical models and heuristic (experience based) rules. The database has been constructed in generic groups to enable unspecified property values to be inherited from the parent materials and treatments. This is equivalent to the interpolation that human experts would apply to estimate an unknown value.

Over 300 distinct classes of commercially available surface coatings and treatment processes have been identified to be included in the full PRECEPT system, although the current prototype concentrates on a subset of 50.
A subset of materials has been developed which is considered to address a large numbr of needs. At this stage only ferrous alloys, aluminium alloys, copper alloys and cemented carbides are being considered. Other metals and alloys will be added in the future and provision is being made to cater for ceramics and polymers.

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