Bolted Connection Design

This tutorial demonstrates the use of the Bolted Connection functionality in Helius Composite.

We need to design a connection that joins two laminated composite face sheets. The requirements of the problem are as follows:

Our task is to determine whether a single bolt is adequate for the requirements of this joint or if we need additional bolts in our connection. We will start by designing our connection with a single bolt.

  1. With Helius Composite open, click Bolted Connection from the Toolbar menu.
  2. Change the number of Rows and Columns to 1.
  3. Use the default AlukoCPL1 laminate for plates 1 and 2.
  4. Use the default Ti-6Al-4v material for the bolt.
  5. Set the Diameter of the bolt to 0.25 in.
  6. Set the Overlap = 3 in.
  7. Set Z = 0.75 in and X = 1.5 in to center the bolt in the joint.
  8. Set F = 2100 lb/in since the joint needs to withstand a tensile load of 3150 lb (2100 * 1.5 = 3150).
  9. Examine the model of the connection to verify that all measurements are correct.

  10. Click Calculate.

On the Results tab we can see that both Plate 1 and Plate 2 experienced bearing failure. The bearing failure mode indicates local crushing of the laminates around the edges of the bolt hole. In addition to bearing failure, we see that the fastener margin is less than zero, indicating the bolt itself has failed. This single bolt connection design is not adequate to meet our design requirements.

Let's add an additional bolt to our connection.

  1. Switch to the Set-up Parameters tab.
  2. Change the number of Columns to 2.
  3. Set X = 1.0 in and Sx = 1.0 in to center the bolts in the joint.
  4. Examine the model of the connection to verify that all measurements are correct.

  5. Click Calculate and ignore the warning about the E/D ratio.

On the Results tab we can see that no failure is predicted in Plate 1 or Plate 2. Additionally, the fastener margin is greater than zero now, indicating our bolts will not fail. We can see that two bolts are required to meet the requirements of this connection design.

Let's go one step further now and determine if better performance is achieved by using two columns of bolts or two rows of bolts.

  1. Switch to the Set-up Parameters tab.
  2. Change the number of Rows to 2 and the number of Columns to 1.
  3. Set X = 1.5 in, Z = 0.5 in, and Sz = 0.5 in to center the bolts in the joint.
  4. Examine the model of the connection to verify that all measurements are correct.

  5. Click Calculate.

On the Results tab we can see that once again, no failure is predicted in the plates or the bolts. If we look at the bearing, shear, and net tension margins, we notice that each value is lower than our original two bolt design. While this connection will meet our needs, it does not perform as well as the previous design.

Parent topic: Tutorials