Hello all,
Thanks in advance for the help. I am simulating the fatigue propagation of an edge-cracked plate. I have the model in N and mm units. I found a reference C and m (C=1.5e-11 MPa.m^0.5 and n = 2.75), where units are written as mentioned. For my case, I am converting the C values in mm/cycle(MPa.mm^0.5)^m units using the exponent. I want to know if this is the correct approach or am I missing something. Thanks.
Hi Shaheen,
The following web site might help.
Simon
https://zentech.co.uk/software/zencrack-support/unit-conversions
Hi Shaheen,
For example, 1MPa.m^0.5 = 31.62MPa.mm^0.5=31.62N/mm^1.5.
The pictures attached show text from BS 7910:2019.
Regards,
Simon
Thank you, Simon, for explaining it so nicely. Now, I understand where I'm going about the unit conversion. I have a follow-up question. I am using mm and N for my model, and I am converting C values accordingly. When I use the Paris law equation to calculate da/dN based on the SIF from Abaqus, do I need to use any conversion factor for deltaK? Currently, I am using the equation only because I understand that Abaqus gives consistent units. Thanks.
Shaheen
Hi Shaheen,
I assume that you are getting the SIF from Abaqus using something like the following option:
*Contour Integral, crack name=Crack-1, contours=10, type=K FACTORS
If yes, your SIF will be in N and mm units, and this would be the correct value to use for a C based on N and mm units.
Regards,
Simon
I got it. Yes, you are right about extracting SIF values from Abaqus. Thanks again; I appreciate your quick response.
Shaheen