Influences on the Stiffness of Riveted Joints in Finite-Element-Models

For the modelling of riveted joints in finite element models it is state of the art to connect the parts by springs (BUSH elements) connecting single nodes on the meshes. The stiffness of the joint is often calculated according to the Huth-formula.

The application of this approach for coarser models as used in aerospace industry results in similar joint stiffness compared to analytical models. But it could be observed that with a finer discretisation the stiffness of the joint will be a function of the discretization. Therefore in the model an effect can be seen which is not physical. The classical approach in the finite element method to increase the accuracy of the analysis by finer mesh densities does not hold any more. The predicted load in the model becomes a function of the discretisation!

Due to the finer meshes also in the aerospace industry this behaviour becomes more important especially in models with different mesh densities. A modelling technique will be presented which overcomes this drawback and only physical properties are used to describe the joint.

Beside this influence there are other estimations for the stiffness of the joints which will be compared to the Huth approach.

 

The Author

Dr. Christoph Katzenschwanz
Sarah Giehler
Acentiss GmbH