Multistate Feature Modelling of a Very Complex Design Feature

This paper presents a Knowledge Based Engineering (KBE) application developed for the aeronautical sector. Specifically, this paper describes a KBE application that aids on the definition of the contact interface between turbine discs and blades of low pressure turbines, namely the firtree. Designing firtrees requires more than 60 different entry parameters, a check for static stresses, de-featuring for fatigue finite element analysis and as cast design for manufacturing and weight management purposes. The application delivered at first the typical benefits of KBE applications: significant time savings, error reduction and standardization. However, the challenges posed by the aeronautical industry, quickly pushed designers out of the standard agreed topology for the firtree. This raised the typical issue on development time and maintainability of KBE applications. The challenge was partially solved through designer knowledge capture and reuse in the form of a User Defined Feature library integrated in to the original KBE application.