Which joint conditions should I choose for a line hinge or a line release in order to couple surfaces by means of end releases?


The differences can be explained using an example (see the figure), which compares the results of a nonlinear calculation with the results of a linear calculation. You can find the model file under Downloads below.

The left and middle models have linear line hinges. In the left model, end releases are defined in ux and uy, and in the middle model, it is only defined in the direction ux. In the right model, end releases are defined in ux and uy, however, there is a pressure contact between the surfaces. These surfaces also cannot intersect to pressure.

When checking the results, it is obvious that the left model is too weak: the surfaces intersect into uy due to the end releases. On the other hand, the middle and the right model give the same results.

It is often reasonable to keep on one linear calculation, if possible. Therefore, the middle model is most favourable for the numerical analysis, although the right (nonlinear) model is closer to the reality. However, the example is only a small comparison model. In reality, you would probably not use the spring in uy/uz, but instead assign the force to a tie rod. Also, that is why the middle model without uy is recommended.

The consideration of end releases between surfaces is also described in a technical article of our Knowledge Base, which you can find under Links below.


line hinge line release end releases between surfaces



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