Automotive Formed Sheet Metal Bracket

THEORY

The industry standard for interfacing metal parts on the generally manufactured BIW automotive chassis seems to be largely produced via sheet metal stamping and forming. In cases where rigidity/strength and/or geometric complexity is required (such as portions of the suspension subassembly), aluminum casting looks to be the industry standard. Injection molded parts may be used in certain smaller-scale electrical interfacing scenarios. Additionally, composites have exceptional potential for incorporation in almost all automotive geometry including BIW chassis, interfacing elements, outer aesthetic elements, etc. 

Alternative Methods: Casted aluminum module w/ native ribbing, Injection molded part w/ native ribbing

• Both of these methods would allow a more robust topological interface between teh rectangular module and the body panels because it is easier to include variable surface curvature into the design. Additionally, the bracket with these methods would be constructed in one piece. 

Attachment options and alternatives (depends on rigidity requirements)

• Riveted and bonded bracket to body panel, spot welds, straight welds

ASSUMPTIONS, DECISIONS, OBSERVATIONS

• Questions

  • How many sides of the module can be covered? How many need to be open?

  • Does the module have native mounting locations?

  • Does the bracket need to be replaceable and/or semi-modular?

• Assumptions

  • Rectangular module is an electronics enclosure

    • Assumption made on nature of enclosure and orientation (sensing systems that require verticality) and weight of enclosure (1kg)

    • In the case of sensing systems within the rectangular module, a robust interface between the body panel and the module is necessary

  • No native mounting locations on plastic module

    • None shown in given CAD model

  • Overall bracket can consist of two separate pieces (no mention of 'one-piece bracket')

  • Assuming panel shown in CAD is an inner body panel (confirmed)

    • If metal body panel is inner, then mechanilca joint to interface bracket might be possible

      • Most likely this is an inner body panel, as bracket would not mount to outer aesthetic panel

  • Assuming plastic rectangular module can be put in compression along x-axis (necessitated by fixing scheme of module to formed bracket)

• Decisions

  • Thickened body panels in given 3D model for the sake of renderings and showcase of bracket design

  • Using flat circular geometry (perpendicular to the backside of Module) as a weldment guide. Initial thought was to use this surface as a mechanical mount

DRAWINGS (Technical for production [not toleranced], Hand)

NEXT STEPS

FEA

• Some CAE simulation or FEA is the first thing that should be done in the validation of this design. Alternative designs should then be created and the respective FEA compared

Fabrication & Testing

• If costs are reasonable, each design of the bracket should be fabricated and tested in practice as fast as possible. This might include extensive fatigue, vibration, and/or corrosion testing

• Testing: Actuated servo system that is tested against output data from the rectangular module; keep testing until data output is within a certain margin of error

Iteration

• Based on the rigidity requirements of the module and failure/testing from previous steps, iterate on the design and eventually find something that is satisfactory. 

Tolerance Analysis for Production

• Communicate with the manufacturing outpost for an understanding of tolerances that can be achieved with such a design. Develop the tolerancing loop and build to test.