Ownership
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| title | Material strength of Acrylic (Plexiglas), PETG 3D printed plastics. |
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[1] Acrylic
Yield Strength: 64.8 - 83.4 MPa (Average value: 75.4 MPa)
Young’s Modulus: 2.76 - 3.30 GPa Flexural Modulus: 2.96 - 3.30 GPa
Flexural Yield Strength: 98.0 - 125 MPa (Average value: 109 MPa) [2] PETG
Yield Strength: 28.3 - 58.6 MPa
Young’s Modulus: 1.10 - 20.3 GPa (Average value of 2.65 GPa) Flexural Modulus: 1.17 - 2.76 GPa
Flexural Yield Strength: 39.2 - 88.9 MPa (Average value of 69.5 MPa) In short, Plexiglas is a strong enough viable alternative for the side walls of the cover. Gel-coat
Protective finishing layer for composite surfaces.
Leaves a hard smooth surface good for sticking on adhesive.
Requires sanding and buffing for a smooth surface.
If painting the cover, apply gel-coat first then paint over it.
Source:
[1] http://www.matweb.com/search/datasheet.aspx?bassnum=O1303
[2] http://www.matweb.com/search/datasheet.aspx?matguid=4de1c85bb946406a86c52b688e3810d0 |
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| title | Material Strength of Fiberglass Foam Core Composite. |
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Assuming quarter inch thickness of all fiberglass (no foam core).
This is to make calculations easier, results might be the same with a foam core or even better. Fiberglass composite flexural strength- 350Mpa.
Fiberglass board of dimensions 0.7m x 0.5m x 0.00635m.
2 x 70kg humans acting as force.
3 point bend test.
Result stress is 72MPa using formula below.
Stress is less than yield strength. Which means a quarter inch thickness is more than enough and could be thinner.
Note that results are theoretical, but results are no where close to yield strength.  |
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| title | Foam Sandwiching and Resin |
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Standard epoxy resin is a good choice for fiberglass.
Has heat resistance of up to 150C. Enough time for occupants to escape vehicle in a thermal runoff situation. Resins in general melt polystyrene and styrofoam foams so they cannot be used.
Polyurethane foams are a good alternative. Foam are bought in large thick sheets, they can be cut down into size using hot wire foam cutter.
Composites Canada carries urethane foam which is a good place to buy from. |
Summary of materials to buy
Fiberglass - 9oz or similar woven cloth
Resin - Epoxy resin
Foam - Urethane foam
Quantity not determined yet.
All available on compositescanada.com
Math
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Manufacturing Detailing
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