Folder Path

D:\Users\Roo\Documents\GrabCAD\MSXIV sims\MS-CHASSIS\Spring 2021 Reinforcement Sims

File Name

August 25_Rev5.1

What to include?

1. Scope is Front Bar simulation

2. Engineering Data

3. Geometry (and manipulation) (and rationale)

4. Model (ACP Pre)

   1. Good to mention contact tool procedure and folders you used to organize your work

5. ACP Setup

Slide Deck:

Advisor FEA Review Meeting_2021-08-28

Meeting Notes

Tom + Kevin

Fixing the bar and running chassis

The contact with the chassis being bonded could be a large source of error

• Matt - can lead to lower stresses; but not drastic changes

  • Matt - (MS12) frictional and sliding contact; one node closes to the collision object near the centre to prevent it from sliding

    • prevents it from flying into space; there can be other options.

• Shalin - (MS12) fixed points on the chassis and ran the bar into the chassis

  • Matt - not what he remembered

• Shalin - have you tried simulating with no masses

  • previously done back in may – no large

  • simulation of no mass is good

  • as you add mass, you should watch how it trends

    • 1 human

    • 2 human → exponential increase can indicate something is wrong

Mesh convergence study-

• Matt - not surprised that it didn’t compile

  • it is finnicky in how you can get results that are proper

  • don’t think it’s the mesh size is the thing hurting you and also not surprised of the result being seen

• Shalin - mesh convergence may not be the main issue right now

  • 5 mm element change would not give an order of magnitude difference in result

  • just set a size that runs relatively quick and get your geometry/results to work with that

• Connor - reinforcements. Have we tried local refinements to the mesh? Are there areas that should have a greater concentration of elements (like around the gussets for example) ?

  • Shalin - x elements in gussets but beams are your global setting

  • refine locally at gussets will get better capture at those locations

• Matt- understanding the effect of mass addition into simulation would be more insightful than accuracy checks

  • adds the most confidence to the simulation

  • previous investigation

• Shalin - Model in L-shaped extrusion and provide mass

  • set material density and volume of the L-shaped object === 80 kg

• Start with worst case → try same load with no mass; add masses slowly;

• 5G should never be anywhere near yielding

Setup more investigation preparation for bar running into the chassis

• Shalin - need to make really good suggestion regarding where you fix the chassis

• Matt - how would you account for the mass of bb box, passengers

• Matt - distribute the entire mass of the chassis onto the entire thing

  • allocate the additional masses and distribute to the entire chassis

Tom - time crunch

• run it again - same constraints - run no mass

  • if mass is not the concern, start looking at how it is constrained can be a factor

  • eliminating major factors and narrowing the potential factors

    • Idea: remove the complexities and analyze it on a simple level

  • suspect that point masses could be sources of the problem

    • test it unloaded

    • test it masses distributed across the chassis

  • simplifying your model and still missing by a wide margin, there is something potentially wrong from the fundamentals (how you sim it)

Summary of Action Items

As per shalin and matt:

• try simulating just the chassis for the worst case orientation with no masses

  • then keep adding masses to check for exponential increase (unreasonable)

  • Shalin’s suggestion of L-shaped passenger (geometry+density =80kg)

  • distribute the additional masses of the entire vehicle across the entire chassis and see how that runs

• make presentation and send to advisors for offline review (see unclosed items)

  • take a look at kimberly’s studies on making the bar go into the chassis with the chassis stationary

  • also take a look at doing what MSXII did for having the contact between the collision object and the chassis be frictionless

    • frictional and sliding contact; one node closes to the collision object near the centre to prevent it from sliding

Unclosed Items

Fixing the chassis and running the bar into the chassis

friction contacts

^^ weren’t able to conclude or no ground basis of justification

• reached to that point – didn’t reach out to advisors for review

  • that is the time to bring in the advisors for review