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Pipe supporting

This example shows how to build a FEM analysis model for a pipe line. The pipe line is loaded by its self-weight, by the content weight of pipes and by a temperature load.

Create a new study

  1. Open model VXPLA-MainAssembly from project EXP-Plant. Go to FEA state by selecting FEA >  fem_state_1.png FEA for Beams and Frames from contextual menu.


  2. Select the assembly Water-IN-1 and create a new study by pressing fem_12L.png New study.


  3. Only the straight pipes are valid sources for beam elements so the pipe elbows are excluded from the analysis. The welded connection between pipe and elbow can be modeled by a fixed connection between the end nodes of connecting pipes.
    _1.png

Link nodes

  1. Select all parts of the study by pressing Select parts from the contextual menu of the active study in study tree.


  2. Link the nodes of selected parts by pressing fem_22L.png Link from the contextual tab.


  3. Set the tolerance to Manual and 110 mm because the distance between pipe ends is approximately 108 mm. Now the pipe end nodes will be linked between each other. Set the connection between nodes as vxfem_preset2.png Fully connected. In practice it have the same mechanical behaviour as the pipe ends would be welded together with an elbow. Link nodes by pressing OK.
    _2.png

Set supports

  1. Set the end node of the pipe next to a flange supported by selecting it and pressing fem_preset2L.png Fixed from contextual tab.
    3.png


  2. Insert node to a pipe line by selecting the pipe and pressing fem_14L.png Insert node. Insert node in the middle point of the pipe support.
    4.png


  3. Set support for the inserted node. Fix the translational degree of freedom in Y direction. Fix also the rotational degree of freedom in X direction. This assumes that the pipe is not free to rotate about its axis at the support. Check that the Local Coordinate System is selected for the node.
    5.png

Set loads

  1. Add content weight as load for all members of the study. Select all parts of the study and press fem_18L.png Properties from the contextual tab.


  2. Set the content weight on by pressing Use checkbox from the Content wight branch. By default, the content density is the density of water. The default value for inner area is calculated from the geometry of 3d model. The inner area and content density can be overwritten by user.


  3. Set the temperature load by selecting fem_8.png Temperature load from the ribbon tab. Set the value for temperature load. 60 °C is used in this example.


  4. The analysis model is now ready for solving.
    _7.png

Solve the study

  1. Select  femsolid_4L.png Solve from ribbon tab. Change stress plot to Displacement DY and results display to Diagram. The support forces are shown when Show support forces is selected. From the diagram can be read that the maximum displacement of the pipe line is approximately 10 mm.
    _8.png


  2. Examine how the displacement is changing when an extra support is added. Quit the FEA Results dialog and insert node in the middle point of the longest pipe. Set support to it and solve the study.
    _9.png


  3. From the diagram can be read that the maximum displacement is now only approximately 1 mm.
    _10.png