Hood Panel

The fastening method alternatives for the hood panel are aimed to be permanent, efficient installation, and cost-effective.

Surrounding panels: Side panel (driver’s side and passenger side), headlights, bottom panel and bulkheads?

Epoxy Adhesive

• Applied to fix it to the side panels and bulkheads

Flush-Mount Blind Rivets

1. Flush-Mount Rivet

• Aluminum and corrosion-resistant

• Sizes diameter (Thickness of material): 3/32” (0.062”-0.125”), 1/8” (0.092”-0.625”), 5/32” (0.062”-0.5”), 3/16” (0.188”-1”), 1/4” (0.188”-0.375”)

• Cost: ~$9.40 / 100 pieces

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https://www.mcmaster.com/rivets/aluminum-flush-mount-blind-rivets/

1. Flush-Mount on both sides Blind Rivet

• Zinc-plated, and mild corrosion resistance

• Sizes diameter (thickness of material): 1/8” (0.059”-0.177”)

• Cost: ~$10 / 50 pieces

https://www.mcmaster.com/rivets/flush-mount-on-both-sides-blind-rivets/

Magnets

This option is ideal for holding panels with unusual geometry in place during the adhesive curing process

1. Eastwood magnets to hold panels (

https://www.amazon.com/Eastwood-Stitch-Magnets-Construction-Panels/dp/B016UV3I2O)

1. Epoxy coated disc magnets (

https://www.amazon.ca/Neodymium-Countersunk-Magnets-Permanent-Magnets/dp/B07TRHT5WB/ref=sr_1_14?dchild=1&keywords=pair+of+strong+magnets&qid=1617213443&sr=8-14)

• Magnets can support a 12kg pull force

1. Brushed nickel hook magnets (

https://www.amazon.ca/Lictin-Magnetic-Hooks-6pcs-Magnets-Diameter/dp/B07QDSQHRT/ref=sr_1_2?dchild=1&keywords=magnets+to+hold+metal+panels&qid=1617211910&sr=8-2)

1. Sheet metal magnets (

https://stronghandtools.com/stronghandtools/products/other-magnetic-products/sheet-metal-magnets/)

Hood Mounting Methods & Locations

Calculation Assumptions:

• Entire mass of vehicle is considered in the 2G bump force

• Assuming worst case condition, where the entire load is applied in shear

• Max. shear strength of LOCTITE® EA E-120HP adhesive = 20 N/mm^2 (is assumed to be equivalent to that of the adhesive being cured on Epoxy material for 12 hours @ 65 °C)

Table 1: Proposed Mounting Locations & Method for the Hood Panel

Hood-headlight bonding area validation:

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Hood to Side Panels

There are two flanges on the side panels (Figure 1, below) that would be the mounting locations to the hood panel. Epoxy adhesive would be applied to the mounting locations, and the flange clamped to the hood with a c-clamp or spring clamp (Figure 2, below).

Figure 1: Side panel flange, mounting location

Figure 2: Spring Clamp

Hood to Bottom Panel

The hood and bottom panel have an interfacing bottom edge, where adhesive can be applied. A fixture assembled using 8020 extrusions is used to support the panel as the adhesive cures. Additionally, adhesive tape can be applied to seal these panels together.

Hood to Windshield

Quarter-turn fasteners would be used to fix the hood to the windshield. These fasteners would be mounted along the flange of the hood panel (additional details are included in the windshield document).

There are two flanges on the side panels (Figure 1, below) that would be the mounting locations to the hood panel. Epoxy adhesive would be applied to the mounting locations, and the flange clamped to the hood with a c-clamp or spring clamp (Figure 2, below). Cardboard should be used between the clamp and panel to ensure no damage (make sure that the adhesive does not get onto the cardboard).

A hood curing fixture is used to help hold the hood panel in place to let the adhesives dry and permanently hold the hood panel in place. To create this fixture, 4 small extrusions (flexible lengths between 10” - 20”), 2 extrusions that are exactly 18.11” are used to hold up the bottom panel (460mm) and 2 medium extrusions (20” – 30”) are required.

The adhesive needs to also be applied between the hood and the bottom panel (Figure 3). This connection must be sealed off completely to prevent air from flowing into the car. For this adhesive to dry, weights need to be placed on top of the hood so that it presses down against the bottom panel. Since the hood is at an angle, to prevent the weights from sliding off the hood a curing fixture was made in Solidworks that could support the bottom panel and also provide the weights a surface to lean on (Figure 4). From the side view, it can be seen that the top of the surface fixture will prevent the weights from slipping and can be rested on the fixture. To provide extra support, books can be added to the base of the fixture to make sure that the fixture does not get pushed by the weights on the hood.

Finally, the curing fixture is supposed to be placed below the bottom panel circled shown in Figure 5 below, so that it can hold the weights placed on the hood in place while providing support to the bottom panel and holding it in place. Note: Adhesives need 24 hours to cure before removing clamps/fixtures.