Research and Concept Development
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
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
https://www.mcmaster.com/rivets/aluminum-flush-mount-blind-rivets/
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
Eastwood magnets to hold panels (
https://www.amazon.com/Eastwood-Stitch-Magnets-Construction-Panels/dp/B016UV3I2O)
Epoxy coated disc magnets (
Magnets can support a 12kg pull force
Brushed nickel hook magnets (
Sheet metal magnets (
https://stronghandtools.com/stronghandtools/products/other-magnetic-products/sheet-metal-magnets/)
Calculations
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
Bonding to Adjacent Panels | Method | Validation/Rationale |
|---|---|---|
Side panels | Epoxy Adhesive | Bonding area calculations (Excel attached, below) |
Bottom Panel | Epoxy Adhesive | Modify hood panel to have inward curve along the bottom edge to allow the panel to join with the bottom panel. |
Windshield | Quarter-turn fasteners | Windshield must be removeable, quarter-turn fasteners will be used for windshield mounting to other panels |
Hood-headlight bonding area validation:
Final Design
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. 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).