06l. Guidance for modelling Bell and Spigot type joint


A spigot joint is a type of pipe fitting that is inserted into another pipe fitting, the joint was caulked with hemp rope impregnated with pine resin and sealed in place with molten lead. So, we have to get this molten lead holding capacity to check will the joint remain intact under all the circumstances.

Follow the following steps to Model the Socket and Spigot type joint.

  1. Model 2 separate segments which are not connected to each other. As shown in the figure below.
  2. Now if you zoom at the junction point of both the segment you will see two node no. at one-point A10 & C04 which shows that segments are not connected.
  3. Now Inset the A13 node no. which will be the point of contact between the Socket and Spigots pipe as per the drawing of the joint. As shown in the Figure below the distance D.
  4. Now insert the Inclined support in Z axis to stop axial movement at Node C03 that will be connected to A13. Put the stiffness of the solidified lead in spring rate option. Define the breakaway force at which the solidified lead which is the sealing substance between both the Socket and spigot joint after which the joint will break and get failed.
  5. As a factor of safety define the Line stop support in Z direction, lateral guide in x direction ,resting, hold-on in Y axis at node no.C05 and attached to A13. Put the stiffness of the solidified lead. After analysing the system check if the line stop.guide resting or hold on is taking some loads . Then check these support loads should not exceed the solidified lead bond capacity. If the lead bond capacity is exceeded, then the joint will tear apart.
  6. As a factor of safety define the rotational restraints in X, Y &Z direction which also be defined at node no.C05 and connected to A13. Put the stiffness of the solidified lead. After analyzing the system check if the rotational restraints in X, Y &Z direction is showing some moments. Then check these restraints loads should not exceed the lead bond capacity. If the lead bond capacity is exceeded, then the joint will tear apart.

Note:

The stiffness and Breakaway force mentioned in the figures are just for representation, define your own stiffness and breakaway force values as per the solidified Lead holding capacity provided by vendor.