Evaluation of explicit MBS formalism: Modal matrix of Flexible Body $B_Flextrack is singular.

The error message you provided suggests that the modal matrix of the flexible body, represented by the symbol $B_{Flextrack}$, is singular. This means that the matrix cannot be inverted, which can be a problem for some calculations.

There are a few potential causes for this error. One possibility is that the flexible body is not properly defined or modeled in the simulation. For example, if the flexible body has no stiffness or mass, or if the boundary conditions are not properly defined, this can lead to a singular modal matrix.

Another possibility is that there are numerical issues with the simulation itself. For example, if the simulation is not stable or accurate enough, this can lead to singular matrices.

To resolve this error, you may need to check your simulation setup and ensure that the flexible body is properly defined and modeled. You may also need to check your numerical methods and ensure that they are stable and accurate. If you continue to have issues, you may need to consult with an expert in the field or seek additional resources to help troubleshoot the problem.