Product development is an iterative process, partially due to changes in both company internal and external product requirements, resulting in changes to the product under development. These changes might require recapitulation of design rationale and result in re-doing assessments and syntheses of different kinds. One way to support this work is to proactively model in such a way that as much as possible of the previous work can be re-used. Not only within one product development project but also across and to future ones. Modelling for re-use can be done by documenting design rationale and formalising performed activities as design guidelines or computer scripts. To be able to find and re-use this information it could be attached to the product features which it relates to. Since geometry is such a core product characteristic, especially within the mechanical industry, and is often modelled as CAD-models, this paper presents a review of CAD-model capabilities and restrictions to serve as a carrier of multidisciplinary information. This is done by; enquiring three Swedish companies, exploring an automated Finite Element Analysis method utilising the CAD-model as a carrier of information, and reviewing different CAD software capabilities. Results show that there are at least seven extension techniques, out of which all are currently being used or considered to be in the future, by at least one company. Further, depending on the extension technique, extendibility and human-comprehension of the added information differ.
One interesting method to take advantage of the particular capabilities of Additive Manufacturing is to utilize a combination of lattice-structures and topology optimization. This paper presents the results and experiences from attempting to incorporate these in an existing multidisciplinary design automation system within the aerospace industry. A combined state of art and practice is outlined with discussions regarding challenges in current commercial CAD tools, multidisciplinary design automation, and with respect to aerospace requirements.
Today, CAD-system are used for much more than just geometric modeling. They are complemented by various software and information sources forming a complete environment for handling all life-cycle aspects of the product. In such systems, the CAD-system works as a central hub. The software and information sources may be of various types making the system highly heterogenous. This presents problems with transparency and traceability in the system making long term management difficult. In this paper, a novel tool is presented to keep track of the dependencies between the various parts of such systems providing an overview and making it possible to predict the effect of proposed changes and facilitating long term management. The tool is tested in a highly heterogeneous environment at a manufacturer of aerospace components, with the result that the traceability is expected to increase at the expense of that time must be spent on defining dependencies and meta-information as the system is evolving.
The focus of the research presented in this article has been an integration of a CAD-system and a FEA pre-processor to automatically develop a complete FEA-models in order to make simulation based design possible. The article presents a prototype system that was developed to automate the simulation of the behavior of ski-racks mounted on cars during collision. This type of simulations requires mesh models containing structured mesh, an issue solved in the presented system and that is presented in the article. It is also shown how to make it possible to introduce contacts, loads, constraints, and other FEM-properties based on CAD-geometry.
Design of sheet metal forming tooling is currently based on that experienced tooling designers with good knowledge of how stamping tools previously have been designed and operated in production, apply their knowledge when making a new design. For retrieving former designs, they often need to rely on their good memory. In this paper, an automatic method for retrieving relevant former cases is presented. A major challenge is defining the similarity between the current and the former cases i.e., finding the relevant parameters to include in the CBR (Case-based reasoning) search. This is here addressed by using CAD model parameters both from former components and the tooling for their production. By interviewing tooling designers in industry, a set of relevant parameters has been identified. To arrive at the correct weight of each parameter, a genetic algorithm has been used to optimize the search results. This resulted in a quick and automated way of retrieving the most relevant former cases and presenting them to the designer. The method has been tested on actual cases with promising results. This has the potential of making sheet metal part and tooling design less reliant on memory and experience.