Learning Forum

[jordan.hannagan]

Hey all

Looking for some help on typical values used for C and p for Cowper-Symonds strain rate model, part of Mat_Plastic_Kinematic model. This is for Australian reinforced concrete, most likely 500N reinforcement steel, and 40-55MPa concrete. I am running a blast analysis. 

Have looked through some studies but the values seem to vary quite significantly. 

Thanks

Jordan

[Ram Gopisetti]

Hi Jordan, 

The calibration procedure is necessary to determine the parameters C and P based on the provided strain rate model, which modifies the yield stress using the relation:

σ = σ₀ × [1 + (strain rate / C)^(1/P)]

Please note that this formulation is a simplified representation of strain rate dependency and may not fully capture the material's behavior under dynamic loading.

For a more comprehensive and robust representation of strain rate effects, consider using MAT_024, where the strain rate dependency can be defined using the tabulated data available in the LCSR, specifically the stress-strain curves across various strain rates. This approach provides a more accurate depiction of material response than simply scaling the yield stress.

As ANSYS employees, we are unable to provide specific quantitative values for the C and P parameters. Also, such graded steels are not pre-calibrated or readily available in any material databases.It is important to review and understand the assumptions made in each study that defines these terms.

For improved modeling accuracy in blast applications, we recommend exploring MAT_084 with reinforcement, which may yield more realistic and reliable results.

Best regards,
Ram