A Concurrent Approach to Manufacturing Induced Part Distortion in Aerospace Components
It is not possible to predict part distortion in aerospace components to the required level of accuracy when considering component tolerances. COMPACT was the first initiative to propose a multidisciplinary approach to the prediction and resolution of this problem. Work was undertaken in certain areas, where other areas being described as 'black art', were ignored. In COMPACT, research was conducted in the areas of material processing, manufacturing and design, so that a proof of concept could be obtained.
The objectives of COMPACT were:
The creation of new knowledge in traditional areas, such as materials, manufacturing and design. The outcomes of these elements of the project would stand on their own, as with all EU-funded work.
Finite Element Method technology was needed to simulate the work in each area. New knowledge would be generated to extend the applicability of this technology and achieve greater accuracy in a three-dimensional context. A methodology would be researched and developed that enabled simulations from the three different areas to be integrated. This would enable the prediction of residual stress and distortion due to its redistribution through component design.
Knowledge-based process engineering would be used as a novel research philosophy. Work undertaken enabled the development of a knowledge-enabled process modelling (KEPE) methodology. Subsequently, a system would be developed, which would demonstrate the re-use of the knowledge gathered from the three areas of expertise. The system would then enable engineering compromises to be made in distortion management.
The work would eventually allow cost savings to be made in manufacturing through the minimisation of 'scrap', repair, concessions and the expensive re-processing of aluminium. By looking at design in the light of residual stress, it was expected that the design work would enable engineers to optimise geometrical shapes and produce lighter components and thus, lighter aircraft.
It is estimated that tens of millions of euros are spent every year in an attempt to either avoid or remedy the distortion in components. Part distortion is a function of residual stress and is caused by the complex relationships between material processing, component design and manufacture. The work programme was developed around these three fundamental streams of research and consequently adopted a truly concurrent approach. Two further research streams enabled the bulk of research findings to be effectively applied to problem solving. Research would then be used to gain a greater degree of understanding across the engineering disciplines and create a knowledge base using a process-orientated approach. Finite element modelling was used to develop three-dimensional functionality that would enable multidisciplinary simulations to be made. The knowledge integration work used this technology in order to assist or guide cross-functional engineering teams in the decision-making process.
The project was divided into 9 different work packages (WP), with each package having a specific objective. Two WP's were support work packages: WP1 (Project coordination, exploitation plan and dissemination) and WP6 (Knowledge Integration). The 7 other Work Packages were research targeted: WP2a (Materials - Effect of material processing parameters on RS), WP2b (Materials - RS determination methods), WP3a (Manufacturing - Machining), WP3b (Manufacturing - Bending), WP3c (Manufacturing - Post machining processes), WP4 (Through process Finite Element modelling) and WP5 (Effect of design on part distortion).
The expected results were:
- Cost savings to be made in manufacturing through the minimisation of 'scrap';
- Repair, concessions and the expensive re-processing of aluminium;
- In the light of residual stress, it was expected that the design work would enable engineers to optimise geometrical shapes and produce lighter components and thus lighter aircraft.
EADS Deutschland GmbH
Institut National Polytechnique de Grenoble
University of Patras
Alenia Aeronautica S.p.A
Airbus UK Ltd.
Enabling Process Technologies
University of Sheffield