The Role of Computational Material and Process Engineering in Future System DesignDr. David Furrer - Rolls-Royce Corp.
The design of components for future products is strongly linked to the development, selection and optimization of material and the manufacturing processes. Application of manufacturing process models is now commonplace within the aerospace supply chain, and efforts are on-going to enhance these capabilities.
More than ever before it is now expected to design very quickly. The three main components that go into a product's design are Geometry, Materials, and Production Process. Most of these have traditionally been dealt with by "good" engineering sense, and then several test trials with a large variety of "improvements" being implemented as production continues. Many of the production and material parameters, and certainly the geometry may now be "modeled" and trials can be run very quickly by simulation largely base on finite element solution methods.
Used appropriately computational tools can:
Reduce cycle times
Prescribe robust manufacturing methods
Lead to enhanced component capabilities
Help select manufacturing parameters that lead to cost reduction
Modeling and Simulation will
Answer engineering questions
save money in the life cycle of the product
The whole concept is benefits driven.
We can think of modeling as a Six Sigma type of tool. We must be able to properly describe all the boundary conditions, and simulation will find the outcome with the least probability of error or failure.
Historically Forging and Casting industries have led the way in using modeling for product design. Casting models show the structure and related properties associated with the solidification and cooling process for a wide variety of mold design and pouring practices. Not only can porosity prone areas be identified, but strain and likelihood of grain nucleation and growth are accurately predicted.
Forging and heat treatment modeling will result in:
reduction of bulk material requirements
reduction of quench cracks
control and understanding of residual stresses
optimization of microstructure
optimization of mechanical properties
In the past it has often been the case that when a part reaches CNC machining steps there is found to be significantly different outcomes from various batches of parts using the very same CNC programs. Modeling the forging and casting processes has shown that these issues are related to slight variations in these practices, and can therefore be better controlled.
In the area of Manufacturing Process - the ultimate goal is to get it right the first time. To achieve this there must be no "non-value added" operations applied to the process as "patches", distortion causes must be identified and ultimate part damage must be eliminated.
Weld Modeling is quite similar to casting modeling, and fundamentally uses the same sort of parameters and boundary conditions.
Other areas of modeling currently in use in the area of materials are:
Coating Process Modeling
Surface Modification Modeling (ie. peening)
Grain size models
Precipitation models
Mechanical property models
These models can answer a lot of "what ifs", as in the case of predicting anisotropic properties of a titanium part. Variation of properties can be identified as specific locations within the part itself.
A great tool for today's design engineer is the "fully parameterized solid model". Once the parameters are in place, the designer is free to change geometries (or morph and existing design into a new one) and then confirm any benefit or problem that the redesign might cause.
The computational design process involves may players who need to all work together to achieve the "get-it-right-the-first-time" result. These include OEM product designers, component producers, material suppliers, software companies, and Universities (to develop the actual models).
Currently the role of computational material and design modeling is maturing and being pulled by the need for faster design by OEMs. Much more work is needed and links need to be established throughout the supply chain. In the future we may see "virtual manufacturing" as a way of expediting products to market. Much of the current state-of-the-art will be published in the upcoming ASM Handbook Vol 22: Modeling.