Some considerations on the contradictions of the theory of Frank-Read sources

The basis of the theoretical explanation of the plastic deformation of metals is the sliding of dislocations and the dislocation multiplication that takes place during the deformation. The best-known interpretation of this process is based on the operation of Frank-Read sources. The article tries to shed light on aspects and theorems that have been known for decades, which draw attention to quite a few contradictions in the theory of Frank-Read sources.