Limitations of “Reinforcement Model” for Reinforced Concrete Modeling

- January 31, 2022 at 1:17 pm
  chmoon
  Subscriber
  Hello.
  I am doing a non-linear analysis of reinforced concrete.
  I would like to see Max Von-Mises Stress on concrete body and rebar body, respectively.
  
  However, when the rebar is set as a line body and the reinforcement model is used, the results are quite different when using the solid rebar directly.
  For example,
  (1) Using the reinforcement model,
  Max Von-Mises Stress of Concrete: 60 MPa
  Max Von-Mises Stress of Line Rebar : 8 MPa
  
  (2) Using a solid rebar
  Max Von-Mises Stress of Concrete: 60 MPa
  Max Von-Mises Stress of Line Rebar : 95 MPa
  
  Ansys Mechanical provides the above results.
  
  When looking at several materials to solve this
  Concrete has
  "ET,MATID,SOLID65"
  In the Rebar
  "ET,MATID,LINK180"
  I think you have to enter the APDL command called
  
  If the above commands are entered in this concrete body and rebar body respectively, the following error occurs.
  ***** ANSYS SOLVE   COMMAND *****
  
  *** WARNING ***                        CP =      0.188  TIME= 10:47:04
  Element shape checking is currently inactive. Issue SHPP,ON or
  SHPP,WARN to reactivate, if desired.
  
  *** ERROR ***                          CP =      0.188  TIME= 10:47:04
  Element 2526, a LINK180 element, has no section or real constant
  information defined.
  
  *** ERROR ***                          CP =      0.188  TIME= 10:47:04
  Link element 2526 references section 2 which is not a link section.
  
  *** ERROR ***                          CP =      0.188  TIME= 10:47:04
  Element 2527, a LINK180 element, has no section or real constant
  information defined.
  ...
  *** ERROR ***                          CP =      0.219  TIME= 10:47:04
  Element 2625, a LINK180 element, has no section or real constant
  information defined.
  
  ************************************************************************
  The number of ERROR and WARNING messages exceeds 200.
  Additional messages suppressed. See ( D:ANSYSProtective
  Wall\_ProjectScratchScrEA2Cfile0.err ) for suppressed messages.
  ************************************************************************
  
  What should I do?
  
  Info.
  ANSYS Student 2022R1
  Material: General Concrete, Structural Steel NL
  Nonlinear Effect: Yes
  Large Deflection: Yes
  Beam Section Results: Yes
  Rebar Cross Section: Circular (R: 5 mm)
- February 2, 2022 at 2:06 pm
  
  John Doyle
  Ansys Employee
  
  It is difficult to say for sure without studying the model set up and assumptions more closely but using solid elements for the rebar might not be characterizing the stress profile very accurately if the mesh is insufficient.Perhaps you are overpredicting the stiffness in bending.The LINK180 by contrast, does not account for bending at all. These are just general statements. Also, how are the concrete and rebar connected?Are the nodes merged with the solid rebar or is there contact between the two bodies? Perhaps the answer to that question might also offer clues as to why the results appear to be different.