Since being founded in 2007, High-Octane Motorsports e.V., a university group at the Friedrich-Alexander University Erlangen-Nuremberg (FAU), has constructed an innovative racing car for Formula Student every year. The student racing series is divided into three categories – cars with electric engines, cars with combustion engines and driverless cars. The High-Octane Motorsports team represents the FAU in the combustion engine category. Toolcraft supported the students with the design and production of their engine mounts. The idea was to manufacture the components using 3D printing. The first step, however, was to use FEM calculations and topology optimisation to ensure they would have an ideal weight. This was crucial because in motor racing a single gram could be the difference between victory and defeat.
High Octane Motorsports e.V.
The Starting point:
Engine brackets hold a key to success
Engine brackets are crucial when it comes to fitting an engine into a racing car, as they connect the engine to the CFRP monocoque. The brackets determine the precise position of the engine and absorb the engine torque of approximately 200 Nm. This requires a rigid connection with the one-piece CFRP monocoque chassis because more than 107 load cycles occur over the lifespan of a racing car. The FAU team specified a number of conditions, including the maximum amount of installation space available, the dimensions of the components, the type and position of the attachment and the choice of materials. The objective was to optimise the engine brackets in terms of weight, force absorption and topology and to produce them using additive manufacturing.
Lower weight without a drop in performance
Toolcraft uses the Siemens NX software package, including the FEM calculations and topology optimisation modules, to optimise its 3D printing process – across the design, manufacturing and reworking stages. During this project, CAD data was used to visualise the amount of installation space available for the engine brackets. Load paths within this installation space were iteratively calculated so that material could be removed from the areas of the components least exposed to stress. This made it possible to work out how much the weight could be reduced by before the components no longer perform as required. To ensure that the construction was as lightweight as possible, the components were made from a Ti6AlV4 alloy. Despite its low density, this material boasts excellent mechanical strength properties, allowing the demanding requirements of motor racing to be met.
Step by step to success
- Preliminary design work to ensure the engine brackets can withstand the pressure (e.g. provision of allowances on functional surface areas)
- Calculation of all forces being exerted, the force paths and the maximum force for each component
- Creation of a simulation model based on the conditions in place (load paths and choice of material)
- Topology optimisation and evaluation of the results
- Additive manufacturing of the components
Victory across the board
Siemens NX enables data to be handled in a streamlined manner all along the process chain, from design and simulation to the preparation of 3D printing construction jobs, allowing robust parts to be produced in a short space of time. This meant that the FAU team, who are working to a deadline, received optimised parts for their racing car without delay. The topology optimisation process reduced the mass of the components by almost 50%. The engine brackets also boast high fatigue strength and this played a considerable role in boosting the vehicle's performance.