Simulation Use and Setup Justification

Owned by Tommy Tran
Last updated: May 04, 2021
3 min read

 

 

  • Is there any guideline for ASC Regs that suggest the method of creating simulations

    • Guidelines what ASC wants to be approved

    • Assumptions on how to model that in a simulation

      • Questioning all the assumptions that we made to create the simulation
        What Matt and Jason referred to when reviewing the FEA

    • Need to start all our design logs with the ASC rules because those are our real constraints

      • Need to find the other relevant info about 5G

  • Why are we doing static structural

    • How did we decide on this

    • Where did 5G come from? Specific wording

  • Exercise of double checking our assumptions

    • Static structural for a dynamics situation - time dependent

      • Roll over - more thought into what a roll over situation looks like?

      • The event that causes the car to flip would be dynamic

  • 2 Different ways to simulate with crashing into a wall

    • Treat it as structural then apply a force from the wall to the car
      Allow the wall to move, roller slider

      • A force balance, static, not time dependent,

      • List of assumptions needed to apply MODS knowledge, it has to be static
        Force is not variable, apply the force over a long duration (so it’s not sudden), deflection/deformation is negligible (does not change the direction of the force)

    • Explicit dynamics situation -- apply a speed to the car

      • If there is a speed on the rotation, there is a time-dependent component. Much less than a full on collision though so maybe that’s why it’s treated as negligible

      • Dynamic assumptions - everything is time dependent, e.g. force, force applied over a short time duration (changes load + material responds differently to the load)

  • Crash scenario is an impact scenario which is different from a static scenario

    • Sustain push vs. punch

  • Note to Self:
    The asymmetry in the top 30 case WALL object

  • There would be difference between time frame snapshot of dynamic impact situation

    • MODS all energy is stored as deformation, e.g. spring, any material with an elastic region would store energy

    • Dynamics energy can be transformed into vibration, heat, sound, etc. which can cause the material to fail

      • Ductile material can fail in a brittle behaviour despite being a ductile material. Associated with the nature of how quickly the force is applied in an impact scenario.

  • Dynamics assembly has shocks therefore can be done purely on FEA

    • Hitting a bump with a shock absorber vs not having one

    • Rate at which the force is applied is almost instantaneous
      Deformation doesn’t give time to transfer the force

    • Shock ramps up the force that it transfers the 

    • Suspension is a four bar linkage that allows all forces to be transported through that

      • No shock absorber - 

      • Absorber - holds the springs and wheels in place

    • Absorber - the force transferred ramps up based on the deformation of a spring

  • Crash impact is when you bottomed out on your springs

    • Do rules force us to use static structural simulations only? Cze they don’t trust us to do dynamics simulations?

    • Before anything, should double check the rules to verify why we are doing simulations, procedures.