Problem with the viscous prefactor of the Kelvin-Voigt model

Good morning,

I have some questions about the viscoelastic Kelvin-Voigt model implemented in VEDA :

1) In the VEDA comprehensive manual, Version 2.0, 2012, p88, I do not understand the reason why you divide by a factor 2 the calculation of the convolutional integral of the Dirac delta.

2) Furthermore, I implemented the model in Excel and Matlab but there seems to be a little difference with the results of the VEDA simulator due to the viscous prefactor. This would indicate that it may be wrong or wrongly implemented.

By simulating a sinusoidal wave, in order to fit your results, I need to change the prefactors into : 7/5 instead of 2 for the approach 7/20 instead of 0.5 for the retract meaning that the actual viscosity you are using in your simulation is 7/10 times the viscosity you define in your model.

By simulating a triangular wave, I even get different prefactors : 1 instead of 2 for the approach 0.25 instead of 0.5 for the retract indicating that the viscosity you are using is 2 times the one of your model.

I do not have any problem with the elastic term (which is only Hertz contact).

Could you help me and get me in the right direction for this viscous prefactor?

Thanks a lot, sincerely,

T.Cugnon