Hi everyone

im looking for an apropriate model for silicone rubber and came across

the berstrom boyce model in jmps from 1998.

when looking at the paper i found someting that was not quite clear to me

and i hope someone here can help me with this. the modle consists of two

networks, A and B, where only network B can bevelop inelastic deformation.

now looking at the evolution law for network B the shear rate, given by

(24), is given by something like

gamma_dot = C1_hat * (\lambda^{Bp}_{chain} - 1)^C2 * tau

to me (and i guess that im wrong here) this looks funny becaurce

starting of with Fp = I gives \lambda = 1. this means that the expresion found within the parathesis above would be zero i.e. gamma_dot would be

zeros what ever value the stress tau takes.

can someone pleas give me a hint here since i guess im not getting this right.

best

magnus