In this example, we start from a 2D frame model.

Firstly, we mesh the vertical columns.

Secondly, we mesh the horizontal beams while making sure that these are not connected to the vertical columns.

After the steps above, we end up with duplicate (coincident) nodes at some chosen locations connections.

We then create Moment-Hinge Link Elements between connecting each pair of duplicated nodes.

The full process is the following:

Step 0: Open the provided Input file or follow the steps in ADINA Primer example 72

Step 1: Mesh vertical columns

Step 2: Mesh horizontal beams preventing mesh connectivity between beams and columns

Step 3: Define Link Elements (Element Group, Material Model)

Step 4: Assign Moment-Hinge Link Elements

Step 5: Run the Analysis

Step 6: Open the Results File

Step 7: Obtain Moment-Rotation curves for the Moment-Hinge Link Elements

Step 8: Obtain Base Shear-Top Displacement curve for the whole Structure

 

 

 Step 0: Open the Provided Input file or follow the steps in ADINA Primer example 72

• File > Open Batch > PartialRestrainedMomentFrame_1.in
• The model includes the following:
  • Geometry, including auxiliary points 444 and 555 to assist meshing
  • Elastic material for beams elements (beams and columns in the structure)
  • Cross-section properties for beams and columns in the structure
  • Applied Fixed supports
  • Applied Loading (gravity forces and prescribed displacement), Time Functions and Time Steps
  • 2D degrees of freedom are active only (TX, TY, RZ)
  • Large displacements assumption

 

 

Step 1: Mesh vertical columns

• Go to Meshing > Create Mesh > Line and assign Element Group 1 to Lines 1, 2, 3 and 4 using Aux Point 555.

 

Step 2: Mesh horizontal beams preventing mesh connectivity between beams and columns

• Go to Meshing > Create Mesh > Line: Assign Element Group 2 to Lines 5 and 6 using Aux Point 444

 

 

 

Step 3: Define Link Elements (Element Group, Material Model)

• Go to Meshing > Element Group: Define Link Element Type and Moment-Hinge Subtype.
• Type a description, for instance “Moment hinges for the first floor”

 

 

• We will define a Moment-Rotation curve, so we need a Link Property Set.
• Click on the three dots next to the Link Property Set drop-down list.

 

 

• Click on the three dots next to any degree of freedom’s drop-down list and then select Multilinear model.

 

 

• In the Multilinear Elastic-Plastic Link Element Property introduce the following inputs:
  • Description (e.g. “First floor beam connection”)
  • Stiffness: 84.8E6
  • Response Type: Moment-Rotation
  • Type of Hardening: Isotropic
  • Moment-Rotation table:

 

Rotation	Moment
0.000234	20350
0.02547	21377
0.21124	8140
0.4	8140

 

 

• In the Multilinear Elastic-Plastic Link Element Property, click on the Add button and introduce the following inputs:
  • Description (e.g. “Second floor beam moment-rotation connection”)
  • Stiffness: 19.25E6
  • Response Type: Moment-Rotation
  • Type of Hardening: Isotropic
  • Moment-Rotation table:

 

Rotation	Moment
0.000568	10938
0.020568	11492
0.119657	4375
0.4	4375

 

 

• Click OK and note that we now have two Plastic-Multilinear Link Element Properties defined. Click Close.

 

 

• On Link Property Set 1, select Property 1 from the ‘r’ degree of freedom drop-down menu and click on Add.

 

• On Link Property Set 2, select Property 2 from the ‘r’ degree of freedom drop-down menu and click on OK.

 

• In Element Group Number 3, select Property Set 1 from the Link Property Set drop-down menu. Select all three options (Nodal Forces, Stresses and Strains, Section Forces and Moments) under Results Saving.

 

• Click Add to define Group Number 4, add a Description (e.g. “Moment hinge for the second floor”), select Property Set 1 from the Link Property Set drop-down menu and select all three options (Nodal Forces, Stresses and Strains, Section Forces and Moments) under Results Saving.

 

 Step 4: Assign Moment-Hinge Link Elements

We are going to apply the Moment-Hinge Link Elements to the coincident pairs of nodes on each floor. If we display node labels  we can see duplicated nodes at the connections. Beam and column nodes did not connect and merge into single nodes when we meshed the horizontal beams because we set the Node Check option to ‘No’.

 

• Navigate to Mesh > Elements > Element Nodes
• Select Element Group Number 3 using the top-left drop-down menu. Introduce the following inputs and click on Appy:

 

Link Element	Node 1	Node 2
82	8	2
96	9	6

 

 

• Select Element Group Number 4 using the top-left drop-down menu. Introduce the following inputs and click OK:

 

Link Element	Node 1	Node 2
114	11	4
125	12	5

 

 

• Navigate to Meshing > Elements > Element Data and select Element Group Number 3. Make the following changes to this table and then click Apply.

 

Note that Translational degrees of freedom are constrained by default in Moment-Hinge Link Elements, so even if we choose to explicitly specify Translation, the effect will be the same as “Default” in this case.

 

 

 

• Select Element Group Number 4. Make the following changes to this table and then click Apply.

 

Note that Translational degrees of freedom are constrained by default in Moment-Hinge Link Elements, so even if we choose to explicitly specify Translation, the effect will be the same as “Default” in this case.

For the link element 114, however, it is not applied since a displacement load exists at Node 4 (or Point 3) and it necessitates manual application of translational degrees of freedom constraints.

 

 

 Step 5: Run the Analysis

• Go to Solution > Data File/Run… make sure that “Run Solution” is selected and click on Save.

 

 

 Step 6: Open the Results File

• Change the Program Module to Post-Processing
• Go to File > Open and open the porthole file (*.por) containing the results

 

 

Step 7: Obtain Moment-Rotation curves for the Moment-Hinge Link Elements

• Go to Definitions > Model Point > Element Section and add MOMENTCONNECTION114
• Create Element Group 4, Element Number 114, Defined by Label Number, Label #1

 

 

 

 

• Go to Graph > Response Curve (Model Point)…
• Define the following parameters:
  • X Coordinate: Set Variable to Displacement > T-ROTATION
  • Y Coordinate: Set Variable to Force > BENDING_MOMENT-t
  • Make sure both Model Point drop-down lists are set to “MOMENTCONNECTION114”
• Click OK

 

 

 

 Step 8: Obtain Base Shear-Top Displacement graph for the whole structure

• Go to Definitions > Model Point > Node
• Add TOP_DISPLACEMENT, set Node# to 11 (this represents the top-left corner of the structure) and click OK

 

 

• Go to Definitions > Model Point (Combination) > Node
• Add SUPPORT_NODES, type Nodes 1 and 7 in the first two rows and set both Weights to “-1”.

 

 

• Go to Graph > Response Curve (Model Point)
• Define the following parameters:
  • X Coordinate: Set Variable to Displacement > X-DISPLACEMENT and Model Point to TOP_DISPLACEMENT
  • Y Coordinate: Set Variable to Reaction > X-REACTION and Model Point to SUPPORT_NODES
• Click OK

 

 

 

See Also:

A1. MOMENT-HINGE EXAMPLE (VIDEOS)