This presentation was made at the NAFEMS European Conference on Simulation-Based Optimisation held on the 15th of October in London.
Optimisation has become a key ingredient in many engineering disciplines and has experienced rapid growth in recent years due to innovations in optimisation algorithms and techniques, coupled with developments in computer hardware and software capabilities. The growing popularity of optimisation in engineering applications is driven by ever-increasing competition pressure, where optimised products and processes can offer improved performance and cost-effectiveness which would not be possible using traditional design approaches. However, there are still many hurdles to be overcome before optimisation is used routinely for engineering applications.
The NAFEMS European Conference on Simulation-Based Optimisation brings together practitioners and academics from all relevant disciplines to share their knowledge and experience, and discuss problems and challenges, in order to facilitate further improvements in optimisation techniques.
When designing an additively manufactured part many decisions must be taken before being able to manufacture a working product. One first performs a competitive analysis of different systems before preparing a number of new conceptual solutions using creative methods. After having chosen the optimal material, a topology optimisation can be a conducted. Complex geometries are usually only possible through laser beam melting with considerable support structure. The share of this can be reduced by using several iterations thus reducing post-processing costs. Furthermore, it is possible to integrate different functions that normally come with additional parts and weight.
One example of such a part is the active hinge system designed by EDAG, voestalpine and Simufact. Stringent safety and functionality demands imposed on active hinge systems for engine hoods mean they are very complex. In the event of an accident with a pedestrian, they extend the distance between the impacting object and any hard engine components by raising the engine hood. A pyrotechnically triggered actuator kicks in within fractions of a second and raises the hood. These hinge systems can be manufactured by stamping, casting or forging for large-scale production series in excess of 30,000 units per annum. The complex kinematics involved require many individual parts (approximately 40 components per vehicle) and high assembly and tooling costs. Active hinges made from sheet metal nowadays weigh around 1500 g each and thus generate considerable additional weight in vehicles. However, economic constraints prevent small production runs of between 80 and 30,000 units per annum being covered using large-scale production technologies. Furthermore, design reasons and the lack of assembly space in the front section of sports cars generally prevent sheet-metal methods being used for active engine hood hinges. Carry-over strategies aiming to minimize investments for small production runs usually cause package and design problems due to the adoption of active hinges from large- scale production.
This elaboration intends to exploit the potential of additive manufacturing to solve these mentioned issues and using software for the fully automatic topology optimisation of additive manufactured components. We researched different ways to achieve an optimal solution for a particularly fast generation of complex lightweight structures without the otherwise necessary manual effort in the interpretation of the simulation results. It created different organic-looking lightweight structures that realized material- saving, efficient and cost-effective production with additive manufacturing. The core element was therefore an automatic interpretation of the optimization result and issuing an error-free file for manufacturing. The user generates within a short time usable components in his known technical data workflow with optimal load paths and fully adapted to the AM manufacturing process, i.e. minimal wall thickness.
Due to the complexity in the whole process from design to manufacturing, the idea of this paper is to describe different approaches to design a part like a hinge by using different optimisation tools. The question that should be answered is: what way is optimal for additive manufacturing optimisation.
|Date||15th October 2019|
|Organisation||EDAG Engineering GmbH|