Learning Forum

[mika.loiselle.1]

Hi,
Do you know if MCalibration can be used to calibrate materials for dynamic tests like impacts? Or is it just for traction or compression tests? I’m trying to make a TPU model for impact simulations and I was wondering if I could use impact tests as calibration data to make sure the model is as accurate as possible since it is a nonlinear hyperelastic material. Do you know if that software can allow us to do that?

[Ram Gopisetti]

Hi Mika, 

MCalibration can target the specific solver to build a fully calibrated material model that is compatible with LS-Dyna. For thermoplastics, MAT_318 (TNM_PLASTIC) is an ideal choice, and it can be calibrated using MCalibration by inputting temperature- and strain rate-dependent tension-compression test data, along with creep curves (optional). Additionally, you may explore other material model frameworks offered by LS-Dyna, such as MAT_317, MAT_24, and MAT_168 (for brick elements), among others, for thermoplastics.

Cheers, 

Ram 

[mika.loiselle.1]

Hi,

Thank you for your reply. It helps a lot. By "straint rate-dependent" data, do you mean something like multiple uniaxial tension tests at different strain rate or do I need data from a test with variable strain rate like a dynamic drop test where I would use something like the acceleration as data?

Thanks again for your time,

Mika

[Dennis Chen]

 

Hello, for a urethane foam, I’ve done a project for this exact application and I used www.veryst.com for this kind of material calibration (Jorgen, who created Mcalibration, used to work there). 

They recommended Mat_187 (analytical plastic) or Mat_269 which is a bergstrom boyce rubber material model, which is a FFSE (Finite Strain Viscoelastic) model.   

The key here is to understand these materials are highly viscoelastic with rate and temperature dependent properties.   when getting test data and fit to a material model, keeping these in mind is key.