DUT Racing Formula Student Team Delft Newsletter
April/May
Formula Student Team Delft Newsletter April 2014
dear reader, We have been off the grid for a little while, hence the reason this newsletter reaches you only at the end of May. We can not show you everything that has happened yet though, we have to save some for the roll-out and the competitions! Speaking of which, the DUT14 roll-out will be held on the 13th of June here in Delft, see our Facebook for more information. We hope to see you there! As for the rest of the newsletter, read on to see what we have been up to. Regards, The DUT14 team
Formula Student Team Delft Newsletter April 2014
Team Update
As you will have undoubtedly noticed, we have been receiving part after part here at the office. It is almost like it is the holiday season all over again! Motor shafts, gears, wiring, you name it, we got it. Stay tuned on our social media to see what else we will be receiving in the coming weeks!
It is possible you have seen the videos, around the internet, of Impact Attenuator (IA) tests that are... slightly unconventional? So unconventional, FSG decided to update their rules regarding them? Here at Delft, we are still a little old school though, we prefer the old way of safely using a droptower. It allows for much more accurate results! The tests validated our crashnose design, the DUT14 drivers will be safe in that regard!
We had a stand at the hannover messe, and stood there the entire week with a fantastic team that is also from Delft: the Nuon Solar Team. The DUT13 and Nuna7 attracted plenty of visitors, interested in seeing the engineering behind the extraordinary prototypes.
Formula Student Team Delft Newsletter April 2014
The motors are ready! After Maxim, Chief Powertrain of the DUT14, accompanied by the Chief Electronics/ESO and our Tech Manager, drove up and down to AMK to assemble the motors, they are finally ready for testing, together with the motorcontrollers.
It is finished! It is finally done, the monocoque is ready. We put the holes in the monocoque with the FARO-arm, and by now it is also back from the painter! As promised, the second timeline will be featured in this edition of the newsletter.
We have been at it again. More compound tests have taken place, but the results are beyond classified as of this moment. Follow us online to stay up to date!
Formula Student Team Delft Newsletter April 2014
The Accumulator Electric cars beat combustion cars in every possible way when it comes to racing: maximum torque from zero RPM, torque vectoring, high power density, it all seems great. The one problem is that electrical energy is difficult to store. The accumulator is one of the bottlenecks keeping electric cars from taking over everywhere.
Testing equipment has been built by team members, which allowed to do very extensive testing on different types of battery cells. The equipment allowed to load the cells in the same way as would happen in an actual race. This means rapid switching between charging and discharging large currents. Doing this in house allowed not only to compare the cells in terms of capacity, temperature behavior and charge capability, but it also allowed for doing lifetime testing. As it came out, the final cell should be able to withstand DUT’s abuse for at least 2000 km losing only about 3% of its original capacity.
Since racing is not a very efficient way of driving your car, a lot of energy is consumed. In terms of accumulators, energy means weight. Maintaining a low mass is crucial for the performance of the car. Track simulations in That is, if the voltages of every cell keep between combination with race data from previous DUT cars the correct boundaries. This is taken care of by the have been used in order to estimate the ideal amount self-designed accumulator management system of energy one wants to store in an accumulator. (AMS). The AMS reads every cell’s temperature However, designing an accumulator for a formula and voltage and acts when hazardous values are student car is not all about determining the right measured. The advantages of a self-developed AMS energy. The car draws large currents during include a perfect integration in the accumulator pack, accelerating, but since regenerative braking is complete control of the settings and high resolution used to win back part of the consumed energy, an in voltage and temperature measurements. This accumulator needs to be able to charge quickly as is crucial for getting that extra mile out of your well. Lithium polymer cells are used in the DUT14 battery, which hopefully leads to winning the events! accumulator, since they have a very high specific energy and power. However, these cells are also known for the fact that quick charging is bad for the life of the cell. Furthermore, it can cause dangerous fires.
Formula Student Team Delft Newsletter April 2014
Upright Production A year at a Formula Student team is always a valuable experience, no matter what part of the car you design. This year though, the uprights were a tough challenge. With the tire growing smaller, the innerwheel packaging now offered room to shift to an innerwheel, hubless concept. In itself, the design would prove to be a challenge: a vastly different load-case, combined with the predominant light-weight design philosophy, demanded some serious engineering effort. However, there was also a production requirement to be met. Especially for such a tricky part, this step would be critical to realising the upright we wanted.
Our cooperation with VDL started in November, at the beginning of our detailed design phase. Over the course of the next few months, we learned some important lessons about design for manufacturing. Iteration after iteration, we improved our design, integrating VDL’s pointers and advice, while optimizing the design of the upright. Five months, countless of 48-hour FEMs, coffee and long nights later, VDL approved the design and signed it ready for production.
Last Friday, the long-awaited moment was finally there. Both parts of the upright arrived, and assembly immediately started. By now the rear-uprights are almost fully assembled, and the spindles are prepared for integration to the innerwheel. The gears almost purr when the uprights spin, and the VDL is an international industrial and manufacturing tension here in the offices rises as the DUT14 is corporation, consisting of over 80 operating nearing its moment of driving on all four wheels! companies, situated in over 18 countries, with its head offices in Eindhoven. Our partner, more specifically, is VDL ETG (Enabling Technologies Group). The division is in the business of system integration of mechantronic subsystems. At their disposal, they have some serious heavy-duty machinery, capable of producing within 4/100 of a millimetre in our case, though it could easily maintain higher tolerances.
Formula Student Team Delft Newsletter April 2014
Monocoque Production: Part II Return of the carbon When we left you last timeline, we had just pulled the negative moulds from the carbon plugs. The next step: start on the outer skin of the monocoque. Remember: we need to have aluminium honeycomb between two carbon skins to create the full monocoque. Here, we are using prepregs: pre-impregnated carbon by TeXtreme (which means we will not need to pull the resin through with a vacuum, it is already present in the carbon!).
Once the TeXtreme is in place, it is time to bag up the halves and send them to the oven at the faculty of Aerospace. There, they will undergo a curing cycle of 45 minutes at 120 degrees Celsius.
Once the skin is back, it is time to place the aluminum honeycomb and plywood inserts. These inserts are essential for formation of proper load-paths of the forces that are exerted on the monocoque. The inserts are placed at locations where the monocoque will receive holes for attachment of suspension or aerodynamic brackets for example. Once everything is placed, core, copper mesh and second layer, the halves are ready for their final cure.
Formula Student Team Delft Newsletter April 2014
Once the two halves are back, we celebrated properly with a few beers and happiness all around. From here on, it was a matter of assembling the halves together, after which the monocoque was ready for the painter. The applied paint is provided by Akzo Nobel, it is a special light-weight coating, placed at ABS Den Elzen. The result? See below.
We will not show the livery just yet, and the picture does not quite do it justice, but the monocoque came out beautifully. The livery has been placed by Custom Paint Holland, and the holes have been drilled as well thanks to FARO. The DUT14 is slowly becoming reality!
Formula Student Team Delft Newsletter April 2014
DUT14 Roll-Out Friday, 13th of June 15:00 Markt, Delft
Formula Student Team Delft Newsletter April 2014
Formula Student Team Delft Newsletter April 2014
Faculties: Mechanical, Maritime and Materials Industrial Design Applied Sciences Technology, Policy and Management Aerospace Engineering
Formula Student Team Delft Newsletter April 2014
a d va n c e d
FDI - DICHTUNGEN速
lightweight engineering