Learning Forum

[Rommel Jr. Landicho]

Hi! I have been trying to model reinforced concrete for a while now and I want to try using multilinear isotropic hardening with values specified for shear transfer coefficients, tensile crack factor, and others. It came to my knowledge that these coefficients can only be specified for SOLID65 which is why I will be using MAPDL Commands. 

I have no background in using these commands, most of them are just from youtube and other forums so I would gladly appreciate your help. 

I have already modeled my beam as a SOLID65 element by using this command snippet under the concrete in geometry tree:

/PREP7

ET,9991,SOLID65 
!*  
MPTEMP,,,,,,,,  
MPTEMP,1,0  
MPDATA,EX,9991,,23205  
MPDATA,PRXY,9991,,0.2   

TBDE,MISO,9991,,,   
TB,MISO,9991,1,6  
TBTEMP,0
TBPT,,0.00036,8.35  
TBPT,,0.0006,13.01  
TBPT,,0.0013,22.38  
TBPT,,0.0019,25.44  
TBPT,,0.002,25.5
TBPT,,0.00243,25.5  

EMODIF,ALL,TYPE,9991,
EMODIF,ALL,MAT,9991,   

/SOLU

However, when I unsupress the steel rebars and input the command snippet below for LINK180, there is an error "An unknown error occurred during solution.  Check the Solver Output on the Solution Information object for possible causes." and a warning "Line body with its type set to Link/Truss or Cable has multiple edges. Please ensure that enough constraints are applied to prevent rigid body motion." 

Command snippet under Steel rebars in Geometry Tree:

/PREP7
ET,9992,LINK180 
!*  
!*  
MPTEMP,,,,,,,,  
MPTEMP,1,0  
MPDATA,EX,9992,,20400   
MPDATA,PRXY,9992,,0.3  

TB,BISO,9992,1,2,  
TBTEMP,0
TBDATA,,400,0,,,,   
R,9992,6,,0

EMODIF,ALL,TYPE,9992,
EMODIF,ALL,MAT,9992,   
/SOLU

Command snippet under Analysis Settings

! Used to merge the solid65 and link180

/PREP7
ESEL,S,ENAME,,65
ESEL,A,ENAME,,180
ALLSEL,BELOW,ELEM
CEINTF,0.00001,
ALLSEL,ALL
/SOLU

No output is shown and there is no material model assignment presented in the Solver Output. I am not sure which of the command snippets are the reason for error. Can someone please correct me? Here are some pictures

[dlooman]

You are trying to use the ceintf command to write constraint equations between the link180 nodes and solid65 elements.  This isn't really merging, it's more like just connecting.   If the link180 nodes were coincident with the solid65 nodes you wouldn't need the ceintf, you could actually merge them with the nummrg command.  When using ceintf the solid65 elements and link180 nodes need to be selected.  So you are missing an nsle command:

esel,s,enam,,180

nsle

esel,s,enam,,65

ceintf