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Ultra Light Foam Vehicle Towards The NEZEF Goal

THE CONSTRUCTION OF THE VEHICLE



The construction of our experimental car towards the NEZEF goal includes the following basic stages:

* The design of the external appearance
* The design and the construction of the frame
* The choice of the materials and the work method
* The making of the model in real dimensions
* The construction of the molds and the effusion of the polyurethane foam
* The construction of the polyester upper part and of the windscreen
* The assembling of the different parts and the finishing details


Near Zero Fatality Vehicle Design
 
We selected our final design, taking into consideration the structural restrictions, which the foamy materials and our limited means dictated. Some other constrains were the soft materials that should be used and that the engine should be placed at the back of the vehicle.

Specifications



Dimensions - Weight
Length 2600mm
Width 1500mm
Height 1450mm
Weight 350kg


Volume of The Bumpers (m^3)
Front 0.43
Rear 0.33
Side 0.17


Performances
Estimated Consumption 1.75lt/100km
Maximum Speed 40km/h




1. The design of the external appearance

Our goal was to make a small and light vehicle, using polyurethane foam for the external body. Several versions were designed. Initially we wanted the wheels covered with foam but this would unavoidably increase the width of the vehicle.


2. The design and the construction of the frame

We constructed a light metal frame from steel. We installed a 72cc four-stroke engine with it’s gearbox, right behind the driver’s seat. The suspension is independent at the front wheels and quasi-independent at the back wheels. The braking system consists of a hydraulic circuit and a disk brake, which reacts upon the rear shaft. The motion is transmitted to the back shaft with a chain.


3. The choice of the materials and the work method

Small models from Styrofoam scaled 1:10 were made. Using these models, we produced polyester molds reinforced with glass fiber. Therefore, the only thing left to be done in order to take polyester copies of our initial model was to find an appropriate mold release. We tested various recipies of constitutive parts, so that we obtained the wanted density distribution, according to the manufacturer (Bayer). We also experimented on the colour of the polyurethane foam and several mold-releasing products.


4. The making of the model in real dimensions

According to our final design, as far as the external appearance is concerned, we made a scaled model from Styrofoam. In order to achieve absolute symmetry, we kept the half piece only and we cut it in horizontal slices. From these horizontal slices we produced on paper the plan forms, which we then scanned. The plan forms were processed by CAD program, and were printed at the real dimensions that the construction would have. Those plan forms were cut into sheets of expanded polystyrene of appropriate thickness and by sticking them together we produced more or less the final form of the model in real dimensions. We filled the gaps between the steps with polyurethane foam and we used sandpaper to scrape the surfaces. We then divided the model into two parts: the upper and the lower.


5. The construction of the molds and the effusion of the polyurethane foam

The lower part of the model was covered with several layers of polyester with glass fiber. To prevent polyester from melting the model, it was firstly covered with aluminum foil. The solidified polyester was then cut into four pieces: the front, the rear and the two laterals. All of them were finished to the final shape using sandpaper and were placed in wooden cases in order to create closed molds. We mixed the appropriate mass of the components in large vessels and we effused the mixture in the molds, which were already covered with mold release. Foams were reinforced with plywood panels at the inner faces. After some hours, we were able to remove the cover of the molds and to extract the four lower parts of the vehicle.


6. The construction of the polyester upper part and of the windscreen

The upper part was also covered with polyester reinforced with glass fiber, like the lower. At the polyester part, which was made, we designed and cut the windscreen and the two lateral windows. These were made by Plexiglas (PMMA). In order to form the windscreen, compressed and heated air was used. The polyester was stuccoed, scraped and dyed. Then the Plexiglas components, the lights and the mirrors were installed.

7. The assembling of the different parts and the finishing details


The final stage of the assembling involves the seating and the propping of the several parts. A panel was also constructed by Styrofoam. The internal surfaces were padded with expanded polystyrene foams and covered with plastic, “leather” like materials. Seatbelts were also installed.


Near Zero Fatality Vehicle Design


Final project


created by G.Damaskos & V.Grapsas