Tutorial: Flexible Fastener Optimization
Run and compare the results of optimizations using rigid vs. flexible fasteners.
- Learn about the Huth-Schwarmann formulation for estimating fastener stiffness
- Run a topology optimization using rigid fasteners
- Enable connection stiffness in the Property Editor
- Run a topology optimization using flexible fasteners

Overview: Flexible Fastener Optimization
In Inspire, flexible fasteners can be created by using the Connection Stiffness property, which allows for better approximation of axial and shear stiffness in grounded fasteners, grounded joints, and cylindrical supports. Fastener flexibility and joint flexibility in general can have a significant effect on how loads are carried in and transferred through a structure.
Numerous methods exist to estimate fastener stiffness. Inspire has implemented the Huth-Schwarmann method, but also allows you to specify an independently calculated stiffness.




Type | a | b |
---|---|---|
Bolted metallic | 2/3 | 3.0 |
Riveted metallic | 2/5 | 2.2 |
Bolted graphite/epoxy | 2/3 | 4.2 |
- Configuration:
- d = hole diameter
- Material:
- E = Young modulus
- Indices:
- 1 = Plate 1 (central one in double shear)
As an alternative to using the Huth-Schwarmann stiffness, user-defined stiffness values can also be applied. This is a more common approach when the parts can't be defined using a plate approximation. One example would be a cast aluminum automotive mount attached to a transmission housing. Rather than model the entire system, if only the mount is of interest, the connection stiffness can be approximated and used to give improved results.