Search
Obtaining Constant ...

Clear all

# [Solved] Obtaining Constant A for ABAQUS Implementation from MCalibration BB Model tauBase

5 Posts
2 Users
0 Reactions
808 Views
Posts: 12
Topic starter
(@eugenebraswell)
Active Member
Joined: 10 years ago

What is the relationship between tauBase in the MCalibration BB model and the constant A in the ABAQUS implementation of the BB model? Looking at the math, the relationship seems to be:

A = tauBase^-m [s^-1 MPa^-m]

However, using data and the stated parameters from Dr. Bergstroms dissertation (Figure 5-11), I seem to have found the following relationship:

A = tauBase^m

For example, from Figure 5-11, C1hat = A = 0.6 [s^-1 MPa^-m]. Using the second relationship, I get tauBase = 0.88, which when used along with the rest of the parameters of Figure 5-11 and the data, gives me exactly the same predicted data. If I use the first relationship, I get tauBase = 1.136 abd the wrong curves in MCalibration.

What am I missing here? Thanks.

Topic Tags
4 Replies
Posts: 12
Topic starter
(@eugenebraswell)
Active Member
Joined: 10 years ago

Going along with the previous post, what is the formula for unit conversion between A in terms of MPa and A in terms of ksi?

Topic Tags
4 Replies
Posts: 12
Topic starter
(@eugenebraswell)
Active Member
Joined: 10 years ago

Bump. Could really use some help with these questions.

Posts: 3998
(@jorgen)
Member
Joined: 5 years ago

Sorry for my slow response. If you have the MCalibration software, then you dont need to worry about those details. The software can simply export the model from MCalibration/PolyUMod format to Abaqus format, and you can export to MPa or ksi units right away.

I am also a bit disappointed how Abaqus decided to define the A parameter. It has weird units.

If you really need to, I can provide you with the conversion between the 2 parameter formats.

-Jorgen

Posts: 12
Topic starter
(@eugenebraswell)
Active Member
Joined: 10 years ago

A conversion between the two formats would be greatly appreciated, as it would aid my understanding. Additionally, my MCalibration free trial has run out and there isnt enough interest in my department to purchase it (as far as I know I am the only one working in this area at the moment). Thanks!

Posts: 3998
(@jorgen)
Member
Joined: 5 years ago

Sorry for my slow response. If you have the MCalibration software, then you dont need to worry about those details. The software can simply export the model from MCalibration/PolyUMod format to Abaqus format, and you can export to MPa or ksi units right away.

I am also a bit disappointed how Abaqus decided to define the A parameter. It has weird units.

If you really need to, I can provide you with the conversion between the 2 parameter formats.

-Jorgen

Share: