How to model snow accumulation on vehicles using EDEM

How to improve vehicle sensor safety in snow using Altair® EDEM^TM

Snow accumulation on vehicles is a common problem during winter months. It can affect the performance, safety and fuel efficiency of the vehicles. Therefore, it is important for manufacturers to design vehicles that can reduce the amount of snow that adheres to their surfaces and the drag that snow creates.

EDEM Simulation Files used in this example can be downloaded here:

Download Snow accumulation Simulation Files .zip

Altair® EDEM can help engineers simulate different scenarios of snow accumulation and test different solutions to overcome the most common problems such as:

Snow accumulation on sensors
Tailpipe blockage
Visibility
Windscreen wipers effectiveness

With EDEM, you can perform various types of analysis to optimize the design and performance of your vehicles. For example:

Identify regions where snow is more likely to accumulate on the vehicle body
Investigate how different snow levels affect driving dynamics
Measure the amount of snow to evaluate the risk of blockage and material build-up in sensors, windscreens and air vents

This blog highlights how to use EDEM to simulate snow accumulation on vehicles. You can download the simulation setup from the following link: https://community.altair.com/sys_attachment.do?sys_id=1531997cdb1f3950cfd5f6a4e2961922&view=true

Step 1 - Set the material model

For this simulation we used the EDEM Powders Database as a starting point to obtain a generic snow material model. For this example, friction and bulk cohesion parameters were selected as high to replicate snow. The EEPA contact model is used for this simulation. The link below provides further details and references:

The Elasto-Plastic Adhesion Model (EEPA) (altair.com)

Simple and Efficient Modelling of Powders with the EDEM Powders Database - EDEM - Altair Products - Altair Community

The particle – geometry interaction properties set for this model, have very small impact on the model outcome.

Step 2 – Material calibration

Snow is a complex material that can show different behaviors. To calibrate a DEM model that captures all characteristics of snow is challenging, but you can focus on adjusting the relevant response for the application of interest using the EDEM physics. For example, to study snow accumulation on vehicles, we can use an angle of repose test that measures both the cohesiveness and the friction under self-weight of the snow. Therefore, we can improve the initial material model taken from the Powder Database. For most cases materials should be calibrated and you can find further information below:

Discrete Element Method Calibration with EDEM

Step 3 - Import equipment from CAD

The car geometry has been created using a CAD package. EDEM supports many CAD file types, and geometries are imported to EDEM via the Creator > Geometries > Import Geometry section.

Step 4 – Introduce Material

To create a realistic snow effect around the car, we used different factories that generated snow particles. Each factory was assigned to a specific area of interest, such as the windscreen and the front of the car. The main factory is a geometry above the car called 'factory curved'. The snow particles were randomly distributed within their assigned areas, creating a natural-looking layer of snow on the car. To learn more about Factories in EDEM, watch this brief video tutorial, link below:

https://www.youtube.com/watch?v=iDGrVv3Jx8Q&list=PLGNemB0NFb0Cf__QxGmnC_CODrPZYmWkA&index=4

Step 5 – Processing of the model

The active domain is adjusted only to the front of the car to speed up the simulation. GPU solver is recommended to speed up simulation run time. check the link below for further information about GPU solver:

https://community.altair.com/community?id=community_blog&sys_id=574bad2adbb16d50cfd5f6a4e29619c8

Course: EDEM - Introduction eLearning (altair.com) , check lesson 15 of the elearning course

Note: EDEM simulation files attached

Optional – Integrate with other Altair tools.

You can expand the analysis of your EDEM simulation by integrating with other Altair tools. For example, you can use Multibody System Simulation | Altair MotionSolve to optimize your car design and understand the loads and stresses on the body of the car to ensure desired performance. Also, Altair Activate can be used to build a block diagram model of hydraulics systems in the vehicle. Check the following examples for more information about Altair tools integration:

https://community.altair.com/community?id=kb_article_view&sysparm_article=KB0116838

https://community.altair.com/community?id=kb_article_view&sysparm_article=KB0119769