Iterative Solution Documentation

Owned by Tommy Tran
Last updated: Sept 06, 2021
4 min read

 

Introduction

This page is to quickly take notes of the additional reinforcements added and the stresses observed.

The goal is to reinforce as much as possible until the chassis is under ~200 MPa which is 4130 Chromoly Steel yield strength with a safety factor of 2.

Please take note of:

  • Project file name

  • A quick screenshot

  • Sampled stress results (B Pillar, Side 60, Top 30)

For example,

Scenario

Stress Results (Max S. - MPa)

Scenario

Stress Results (Max S. - MPa)

B Pillar

638

Side 60

946

Top 30

2021

 

Some previous documentation is found here:
Reviewing Sheet Metal Solution - Mechanical - Confluence (atlassian.net)

But, please continue using this page as documentation for organization purposes.

Note: The latest completed iteration is Rev 3.0

Please start this page with Rev 4.0 and create appropriate saved project files.

 

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

 

Rev 4.0 - Fixed Chassis, Applied Force from object

File Name: August22_KL_Rev4.0.wbpj

(Copied from: "July 1_TommyRev.wbpj")

See Rev 4.0 - Fixed Chassis, Accelerating Object for more details.

Goal

  • Previously, we fixed the back face of the collision object and accelerated the chassis into the object. Fixing this face fixes the entire body of the object as it is a single solid body.

  • Rev 4.0 attempts to fix the chassis and accelerate the object into the chassis.

Simulation Set-up

  • The following steps were used to set up the simulations (see sub-page for more details)

    • Suppress existing 5G acceleration

    • Suppress the existing fixed support on the collision object

    • Add new fixed support to the chassis

    • Add the equivalent force

    • Add displacement constraints to control the motion of the collision object if needed

Conclusions

  • stress results can change drastically depending on the fixed supports selected (much higher or much lower)

  • This setup can be used to our advantage to obtain lower stresses however, we will need to justify the fixed supports we choose.

  • Overall, it might be best to stick with the fixed object setup to avoid ambiguities or any issues getting the VDR approved.

Stress Results

 

Max Combined Stress (MPa)

Scenario

Fixed Object

Fixed Chassis

B-Pillar

351.49

304.86

Side 60

648.65

1226.8

Top 30

1374.9

1667.6

B-Pillar case (Fixed Chassis): Max combined stress results.
B-Pillar case (Fixed Chassis): Max combined stress results.

Rev 5.0 - Longitudinal Reinforcements

File Name: August23_KL_Rev5.0.wbpj

(Copied from: "July 1_TommyRev.wbpj")

Notes:

  • Focused on lowering stresses for Top 30 wall case

  • Added a total of 12 longitudinal reinforcement tubes to try to add more resistance to bending during impact

    • all 1” square tubing

    • Testing the effects of a greater wall thickness (0.113”)

  • Note: there are currently interferences with floor panels, changes can be made to the reinforcement placement later

Stress Results

(not done yet, running into errors - some tubes were split into tiny segments?)

 

Max Combined Stress (MPa)

Scenario

REV 2.0/3.0?

("July 1_TommyRev.wbpj")

REV5.0

B-Pillar

351.49

to do

Side 60

648.65

to do

Top 30

1374.9

to do

Rev 5.1 - Longitudinal Tubes

I was able to implement the tube solution and fixed some contacts regarding the collision objects.

 

Max Combined Stress (MPa)

Scenario

Rev 0 (August 21, 2021)

2 passengers

REV5.1

2 passengers

B-Pillar

351

378

Side 60

648

627

Top 30 in project file

**Collision object used is actually Front 30

1374

1010

 

Red = 200 MPa or more

B-Pillar

Comments

Failing only at joints

Ideas for reinforcements

  • Add gussets at each of these joints

  • Sheet metal might be overkill if we are trying to fix these stresses

  • Tubes might not be the best way to reduce stresses at joints

 

 

Side 60

Comments

A lot of stresses on the top catamaran

A lot of stress at the front passengers floor

Ideas for reinforcements

  • Sheet metal over these tubes

  • More tubes at these areas. Basically a sheet metal wall, but made up of tubes

 

Top 30

This image shows that the stresses are lower when the sheet metal reinforcements are suppressed.

 

Comments

A lot of stresses on these longitudinal tubes

Adding the sheet metal reinforcement actually increases the stress

Ideas for reinforcements

  • More tubes in the longitudinal direction (front to back)

 

Note to self:

  • The back bar (collision object 11) is not compiling properly

    • contact is red and open