Discussion of the published manuscript lazopoulos K.A., karaoulanis D., lazopoulos Α.Κ. (2016) «on fractional modelling of viscoelastic mechanical systems», mechanics research communications, 78, pp. 1-5

The paper [20] attempts to solve a one dimensional model of the Zener type viscoelastic model (see Fig. 1 of the paper) replacing the classical time derivatives with a new fractional time derivative that was presented earlier by two of the authors (see ref. [1], [9] and [10] cited in the work). In addition, the authors present the classical solution of what is called in the paper “conventional viscoelastic model” and the solution due to Caputo fractional derivative, which is the solution of what the authors call “existing fractional order derivative viscoelastic models”. The paper seems to have several problems, typos and mistakes that will be discussed as follows