I have entered a line hinge in the center of the surface and the bending moment is not equal to zero at the line hinge. What can be the cause?


If the line hinge has been defined correctly, the problem may consist in the incorrect support definition.

Although the system (see Figure 01) would seem to have the same value, a moment results in the mid-span from the determination of internal forces in the surface.

In the present case, the cause can already be derived from the error message after the load case has been calculated.

This results in very large deformations in the bottom system, so that this already indicates an incorrect support of the surface.


When checking the line supports, it becomes clear that the bottom system is twisting about the global axis Y due to the missing restraint. Ultimately, this leads to the non-meaningful diagram of internal forces in the basic internal force m-x.

If the line support is adjusted, the result is the expected one.


Line hinge Moment Release Bending moment Internal force Basic internal force Surface internal force


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Structural engineering software for finite element analysis (FEA) of planar and spatial structural systems consisting of plates, walls, shells, members (beams), solids and contact elements

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