Hi,
Model:
I am modeling a simple pull out test, 30 inch diameter by 20 in tall concrete cyclinder, with a 25 inch steel rebar embedded 5 inch into the concrete cylinder. The goal is to see what is the stresses of the embeded region for both the concrete and steel rebar. Ultimately, I would try to incorporate the damage concrete plastic model, but that is after I figure this out.
Constraints:
I used the embed funtion to embed the rebar (slave element) 5 inches into the concrete element (master element), fixed the cyclinder along the edges. The concrete is modeled as 3-D stress element while the rebar is a truss.
Loading:
A 10 kip load is applied at the endpoint of the rebar, away from the concrete cylinder.
Steps:
An initial steps and a 1 second loading step with initial increment of 0.0001
Error/Warning messages:
***WARNING: THE STRAIN INCREMENT HAS EXCEEDED FIFTY TIMES THE STRAIN TO CAUSE
FIRST YIELD AT 22 POINTS
***WARNING: THE STRAIN INCREMENT IS SO LARGE THAT THE PROGRAM WILL NOT ATTEMPT
THE PLASTICITY CALCULATION AT 8 POINTS
***NOTE: MATERIAL CALCULATIONS FAILED TO CONVERGE OR WERE NOT ATTEMPTED AT ONE
OR MORE POINTS. CONVERGENCE IS JUDGED UNLIKELY.
***ERROR: TOO MANY ATTEMPTS MADE FOR THIS INCREMENT
Methods:
I have tried partitioning the rebar into 2 sections, embedding only the 5 inches that using the embed command. I have tried it as 1 whole section, and tried with 2 separate parts - instanced the embeded 5 inch part to the concrete, and tied the endpoints of the embedded rebar to another 15 inch rebar, and then apply a 10 kip load to the endpoint of the 15 inch rebar.
I have tried making the initial increments smaller: from 0.0001 to 0.000001, but not not avail.
Material (kips):
Steel
Elastic: E=29,000 v = 0.3
Plastic:
0.0010
600.0023
60.10.015
72.50.05
77.50.1
77.90.15
72.50.175
650.183
Concrete
Density: 8.68056E-005
Elastic: E = 4.99, v=0.2
Plastic:
1.650
2.450.0005
30.0011
4.50.0035
4.40.0059
3.90.0089
3.30.0145
2.80.0195
2.40.0245
20.0295
0.40.0495
Any Suggestions or comments? Thanks!
Ben