LucaRoss
Structural
- Feb 20, 2014
- 2
Hi everyone. I’m modeling a fiber reinforced concrete notched beam, 550 mm long; it’s a three point bending test and I have to plot the CMOD (crack mouth opening displacement)-force diagram in order to compare it with those obtained from laboratory tests. I modeled the beam as a 2D planar part with shell elements. The model is composed of three parts: the left portion of the specimen, the right one, and a cohesive interface. The interface is made of cohesive elements ( COH2D4 type ) and its material is defined by the following parameters:
ELASTIC, type=traction, E=G1=G2=400000 MPa
DAMAGE FOR TRACTION SEPARATION LAWS >MAXS DAMAGE, nominal stress normal –only mode=3.5 MPa, nominal stress first direction = 100 MPa, nominal stress second direction = 100 MPa
My problem is related to the DAMAGE EVOLUTION parameters. I’d like to model it with a displacement, tabular type; but the analysis responds well only when I model it with a displacement, linear type. If I use the tabular type, the cohesive elements don’t deform at all, even if the model is a displacement –control analysis (it’s a Riks step: the stopping criterion is that of the maximum vertical displacement of 50 mm).
With a linear damage evolution and a displacement at failure of 5 mm all is ok, but if I try to model the same softening branch with tabular data, the cohesive elements don’t deform. The tabular data that I tried are the following:
First line: damage variable = 0, displacement = 0;
Second line: damage variable = 1, displacement = 5.
Can anyone help me? Thanks a lot!
Luca
ELASTIC, type=traction, E=G1=G2=400000 MPa
DAMAGE FOR TRACTION SEPARATION LAWS >MAXS DAMAGE, nominal stress normal –only mode=3.5 MPa, nominal stress first direction = 100 MPa, nominal stress second direction = 100 MPa
My problem is related to the DAMAGE EVOLUTION parameters. I’d like to model it with a displacement, tabular type; but the analysis responds well only when I model it with a displacement, linear type. If I use the tabular type, the cohesive elements don’t deform at all, even if the model is a displacement –control analysis (it’s a Riks step: the stopping criterion is that of the maximum vertical displacement of 50 mm).
With a linear damage evolution and a displacement at failure of 5 mm all is ok, but if I try to model the same softening branch with tabular data, the cohesive elements don’t deform. The tabular data that I tried are the following:
First line: damage variable = 0, displacement = 0;
Second line: damage variable = 1, displacement = 5.
Can anyone help me? Thanks a lot!
Luca
