Material Testing Project

Owned by Robin Pearce
Last updated: May 08, 2021 by Tommy Tran
3 min read

Material Testing Tracker

Material Testing Tracker

Introduction

This is the first time that a material testing project has been introduced to Midnight Sun. Previous vehicle designs of Midnight Sun did not include structural components made of composites and therefore did not require further testing beyond just FEA simulations. E.g. the chassis was made fully from 4130 chromoly steel chassis tubes therefore it was sufficient to validate the design using FEA and a safety factor of 2 in respect to the yield strength.

The material testing project for MS14 will encompass testing for:

  1. Structural and general composites that are manufactured

  2. Adhesive bonding joints

  3. Fastener joints onto (carbon fibre) composites

Factors that encourage testing to be done:

  1. Is it a structural component?

  2. Will it be attached to composites? How will the hardware impact the load transfer? How will the hardware damage the (carbon fibre) composites during any stage of installation and operation?

  3. Material compatibility, e.g. adhesive compatibility when bonding with different or new substrates (materials).

Some context of how we design the stack up of our carbon fibre composites:

  1. Setup FEA simulations using a certain stackup

    1. Panel Stackup Sheet - Google Sheets

       

  2. Run FEA simulations with certain loading conditions

    1. If the stress/deformation values are too much, we increase the stack up, e.g. more layers of CF or thicker core

    2. Repeat until satisfied.

How Will this be Solved?

In general, the method of evaluating our composites and joints will be by comparing FEA simulation performance against real-world empirical testing performance.

FEA

Empirical Testing (Real World)

FEA

Empirical Testing (Real World)

Setup FEA Simulation of composite test specimens and loading condition

Setup composite test specimens and test setup

Run simulations to get results for stress and deformation

Run the test to get empirical data of composite performance

Conclusions that can be derived:

  • The general stress values that we are currently referencing using FEA simulation data

  • The actual stress values from empirical testing

  • Compare the stress values of FEA vs empirical testing

    • If FEA stress value > empirical testing, i.e. if FEA model deforms greater than real-world testing → then it means that our design will have an inherent safety factor since our real world manufactured layup stack up is performing better than the simulation.

    • ^^^ This is the ideal scenario.

    • If it is the other way around, we need to be careful of how much our quality deteriorates and try to compensate for the lack of performance by increasing our stack up.

      • Some previous testing in the past showed that we had a good safety factor, but we should do continual quality management for our composite parts!

Important Considerations to Keep in Mind

  • We need to do ample research to make sure we have all considerations covered

    • there are lots of resources on material testing on the internet – some are even specific to or created by solar car teams!

  • We need to contact experts to help validate our assumptions and thought process. Useful experts are:

    • Midnight Sun Alumni: @Matt Suski @Adam Marchand @Adrian Au

    • Professors: John Montesano (Composites Prof)

    • E3 Lab Technician: Mark Griffet

  • Take lots of pictures and keep track of your test specimens

    • Documentation is key if we want to make a solid record of the material testing data and make sure our results are accurate

    • Not much room for failure because we have limited chances to test our manufactured panels

Project Breakdown

FEA Model

Testing Standard Research

Test Reports

Test Specimen Preparation & Processing

External Review and Feedback Implementation

FEA Model

Testing Standard Research

Test Reports

Test Specimen Preparation & Processing

External Review and Feedback Implementation

Learn how to use Ansys Software

  • Static Structural & ACP

Select relevant testing standards

Create test report template

Gather information on what items need to be tested

  1. Find the item

  2. Figure out which testing standards would be most relevant

  3. Create testing plan for it

Create deliverables/summaries to share with experts and get our work reviewed

Setup FEA models for testing standards

Need to select specific panels/parts and setup the correct stack up

Do research and summaries on testing standards

Fill out test reports according to each standard

Create testing plan for each one

Implement feedback so that we have reassurance that our results will be meaningful and reliable.

Run simulations to get results

 

 

Carry out Testing

 



 

Resources:

Panel Stackup Sheet - shows the composite stackup of all our panels

Panel Stackup Sheet

Material Testing Tracker - tracking the progress of the material testing project

Material Testing Tracker