Hello
I am using PFC to simulate UCS test. I used three methods to monitor the axial stress (see attached): (1) based on the stress on the loading wall; (2) measurement circles that cover the whole specimen; (3) measurement circles that cover the center area of the specimen.
I obtained three significant different results of UCS (see attached). I wondering which one should be chosen for UCS? What is the best way to monitor the axial stress in UCS test in PFC? Thanks.
I suggest using the wall-based stress measurements, because these can be compared directly with what is measured in a real physical test. Note that all three measurement schemes are giving the same axial stress during the portion of the test where the specimen is not experiencing any damage — i.e., during the portion in which the specimen is behaving elastically. As the peak load is approached in a UCS test, the damage begins to localize, with some regions unloading, and it is this localization that may be causing the difference in peak values.
Cheers,
David Potyondy
5 Likes
Hello Dr. Potyondy
Thank you for your kind help.
Cheers
Xiongyu