Roof Panel -- Aero-Chassis Integration

Research and Concept Development

Previous Fastening Brainstorming:

  • Revised Ideas:

https://docs.google.com/document/d/18z0ozrzWEZkZP-ABfqe7ZNCzylWeLuY7BOo3UZIwl50/edit?usp=sharing
  • Initial Brainstorming:

 

Calculations and FEA

Final Design

  • The current method of fastening uses adhesive/base studs as seen in the following image

  • Several base studs are to be placed around the panel where they will slot into mounts placed along the chassis

  • Chassis mounts design are currently in progress ( Taking into account conflicting mounts as well as roof props )

  • The general mount design is shown below:

  • Slot is made to accommodate for panel hinging with moving studs

  • A general look at the current layout of the mounts (most likely going to change) :

 

 

To do List:

  • sync with roof props to check any any motion conflicts

  • sync with side panel to resolve top tube conflict ( discussion between DRIs took place, but lead confirmation is needed )

  • Finalize mount design

  • Create jigs for welding ( up to change as mount design changes )

Manufacturing and Assembly Plans

Sample Manufacturing Procedure:

A sample manufacturing procedure is laid out for mount manufacturing, mount fastening, and fastener to roof mounting. This procedure follows an estimated time that may change as we go.

 

  1. Cutting The Mounts ( 3 - 4 hrs )

    1. Total of 6 mounts are cut in the machine shop using either a waterjet or plasma cutter

    2. Mount angles are grinded off using a low grit angle grinder wheel

    3. Remove sharp edges using a file/rasp

  2. Setting up Jigs for Mount Welding ( 3 - 4 hrs )

    1. Jigs are to be set up by hand in the bay

    2. Detail-oriented process, ensuring mounts are level and held in place

  3. Welding the Mounts to Chassis ( 1 day lead time, not much manual labour )

    1. Chassis along with the jigged mounts is sent to the welding shop for welding

    2. Not much to be done manually here, just waiting for the welding shop to get back

  4. Setting up Roof Panel Fasteners ( 4 - 5 hrs )

    1. Spacers are added to the 6 base studs needed

    2. Positioning guides are set in the stud mounting location

    3. Adhesive is applied to the mounting locations

    4. Base studs/nuts are clapped into position ensuring an even spread of adhesive

  5. Removing jigs and mount guides( 1 - 2 hrs )

    1. Remove jigs and positioning guides

    2. Ensure an even weld/adhesive has been applied

    3. If more adhesive/weld is needed, add some

 

Sample Jig Manufacturing Procedure:

Most of the roof fastener positioning guides can be 3D-printed or roughly cut from any remaining sheet metal. The welding jigs for the chassis mounts might need to be machined to prevent any heat from melting them. The one issue that comes about with machining the jigs is that they can’t be bulk produced.

 

  1. Jig and Fastener Positioning Guide Manufacturing (12 - 15 hrs, depending on manufacturing method)

    1. 6 Mounts and 6 positioning guides are needed to be manufactured

    2. 3D printing and machining can be done in house

Fastener Selections

To clear out any hinging concerns from above and also provide a spacer, an adhesive base nut can be used to resolve both those issues.

The base nuts have a 1/4 inch / 6.8 mm height which will work to fill the gaps in between the roof and the mounts. Alongside the spacing, the base nuts will prevent any issue that were to arise with studs not slotting properly.

 

To accompany the base nuts, a hex-head fastener is selected. The bolt selected has a serrated flange to provide a bit of grip onto the mounts.

Some lock tight can be applied a more rigid fit, but may be a hassle to remove every here-and-there. Thus another option could be considered.

 

Links to both components:

Adhesive base nuts: https://www.mcmaster.com/98007A134/ 
Hex Head Screws: https://www.mcmaster.com/92820A415/