ABAQUS Simple Pull out Test

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