Video Brief

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Sprint Goals

• Get leads accustomed to designing relevant components and critiquing each other’s work.

• Making self-driven decisions throughout the entire process, starting from basic requirements + constraints, to selecting OTS components, all the way to sim validation.

  • This is very important as we anticipate to be designing with little direct supervision (i.e we can rely on prev leads so much; being able to think critically for ourselves is huge).

• Getting comfortable with holding each other accountable to our own deadlines.

• Documenting our progress and decisions.

Topics to be Covered

• Force Analysis (hand calculations)

• Off the Shelf Part Selection

• Concept → Design

• Material and Manufacturing Selection

Sprint Introduction

We are challenged with designing the bellcrank, bellcrank clevis, and pushrod for the inboard suspension pictured below. The given parameters are as follows. Requirements and constraints will be at the discretion of each person.

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Purpose of Inboard Suspension: “The main advantages of a push/pull-rod suspension system on a track-focused race car have to do primarily with the ability to move suspension components closer to the ground, lower the chassis of the vehicle, and lower the centre of gravity to improve efficiency in cornering, body-roll, and high-speed stability”(Wikipedia). Additionally it allows for packaging of the suspension to be smaller than other systems.

The given dimensions and component specifications are in the table below:

Specification	Value

Specification	Value
Shocks from MSXIV	Spring Force: https://www.ridefox.com/family.php?m=bike&family=floatx2
Chassis and Suspension Geometry (assume the chassis and control arms can withstand the loads already)	Open
Mass of Vehicle	192kg
Center of Gravity Location
Loading Conditions
Assembly Max Height	Final bellcrank, clevis, and pushrod assembly should not exceed 100mm past the top or bottom chassis members.

Timeline

Note that independent reviews with fellow leads throughout this entire period are encouraged! You are not limited to just the scheduled reviews!!!

Phase 1 [Jan 10-22; ~2 weeks] - Leads Review JAN 15 & JAN 22 @ 2:30PM EST

1. Conceptual Design: Sketches of design concepts, with labels and descriptions where needed to effectively communicate design ideas.

2. Force analysis: Using the diagram of force locations on the model car above, find the center of mass/gravity (CG) for the vehicle, use the CG to determine the load distribution between axles, use the load distribution to find out how much load each independent suspension assembly needs to withstand, calculate how much load each component in your design undergoes based on the front left independent suspension load force.

3. Off the Shelf Part Selection: Ensure that your sketches and designs include what types of off the shelf (OTS) parts you would like to use (e.g. You want to join two components together without welding? What type of fastener will it be? Will you use a pin? Shoulder Bolt? Zip tie?). In Phase 1, the selection process does not need to be specific (diameter, thread length, head type, etc.), but these factors should be considered when designing.

4. Detailed Design: Concepts should be finalized at this point and moved into CAD. An accurate model containing all properly dimensioned components and OTS parts should be drafted (to be done in SolidWorks). Ensure proper modelling techniques are used, each component is a different part, proper naming of each component, properly mated assemblies, CAD files/mock replacements for OTS parts. The final CAD model should look exactly how it is expected to look in real life.

5. Material Selection: Each component should have a material assigned to it based on the requirements of your design. Use past experiences and intuition to select materials for a component (e.g. glass shouldn’t be used as the chassis material of a car because it will shatter upon impact) and refer to the material’s properties to make an accurate selection.

   1. Resources to help with material selection: Material Properties, http://www.matweb.com/

6. Manufacturing Method: How will your part be made? Consider the tools we have in the bay and in the machine shop. Will this part need to be outsourced for manufacture? Ensure you determine one or more methods of manufacture (waterjetting, CNC Mill, injection mould, etc.) for each component.

7. Refined OTS Part Selection: With your OTS parts selected, it is time to specify the exact parts you need for your design to work (with safety factors included). Use websites and catalogues to determine what exists out there and try to select a cost effective part for your design. Try to be consistent and use standard sizes where possible (e.g. A bolt size M6.789 is very specific and unlikely to find, try designing with M8 instead). For example, say you want to fasten two brackets together using a nut and bolt:

   1. Refined Bolt Specifications: Bolt size, bolt material, tensile strength, shear strength, grade (needs to comply with ASC 2024 regs), etc.

   2. Refined Nut Specifications: Nut size (should fit on bolt), nut material, grade (needs to comply with ASC 2024 regs), etc.

Resources to help with OTS parts: McMaster-Carr is a great tool to find OTS parts to fit your design needs (and most of them have CAD files too!), it can be a more expensive option though so once you have a part selected, try to find a cheaper one of equal quality.

In the middle and at the end of this phase, the participants should get together and review each others work, providing advice, feedback, and expressing issues they have experienced along the way.

Phase 2 [Jan 23 - 29; 1 week] - Advisors Review JAN 29 @ TBD

• Based on the feedback from each other, the designer will have time to rethink their approach and patch up any problems that they may encounter.

• This will also help with both giving and receiving feedback; a critical skill moving forward into the design of the car.

• At the end of this phase, past leads and advisors will be providing feedback on the projects based on your presentations made.

Phase 3 [Jan 30 - Feb 5; 1week] - Closing Remarks/Feedback Feb 5 @ 2:30PM EST

• Based on feedback from the advisors, final design changes can be made, as well as reflecting on the approach taken throughout this process.

Sprint Deliverables

The review sessions will be held to share ideas, get feedback, and inspire your teammates! The following deliverables should be presented in a Slide Deck** (MAX 5 slides per presentation (or 5 mins) with 5-10 minutes for feedback/questions):

End of Phase 1:

TO BE COMPLETED FOR JAN 15: 3 Concepts sketched and labelled (1,3)

TO BE COMPLETED FOR JAN 22: load distribution calculated (2), detailed design of one concept in SolidWorks (4), and all required specifications for components (5,6,7).

• Mech-leads review(s)

  • At this time, the mech leads will present their initial designs in the form of a design log to receive feedback from each other.

  • This can be done in small groups (breakout rooms) or as an entire cohort of leads; participant dependent.

End of Phase 2: An updated slide deck, summarizing what was shared last time, and presenting the updates made at the end of the previous leads review.

• Advisor review

  • Here, the leads present their iterated designs to the advisors, again in the form of a design log; similar to the first review just with a more rigorous reviewer.

  • Again, this can be done in small groups (a few leads to each advisor) or as a cohort.

End Phase 3: Cap off the project, making any final changes or tweaks based on the advisor review. Be sure to keep it for your records and as a reference because the rest of the team will be following in your footsteps!

**it is recommended to keep a design log (in google slides format) throughout this project of all decisions/choices made, the log will make finding the content to present easier come review day! See appendix for examples.

Appendix

Sample Design Logs:

Battery Box Thermal Analysis - Design Log

Kevin Bui FYDP FDR - Password is “midsun”