Hi all,

I am implementing visco-hypoelasticity in my FEA code for my research as

given in the 4.8.6 ANSYS manual.

I have relaxation only in the shear modulus and not in the pressure. The

manual doesn't give the explicit expression for the shear elastic stress

term and the pressure stress term. I extrapolated the expressions from what

is given, and the code is not working properly. Can you please tell me if

the following expressions for the shear elastic stress and the pressure term

is right?
If not, please let me know the equations of the pressure part and the elastic stress part.

- Shear Elastic Stress (Sinf)

S(inf,n+1) = Delta(R)*S(inf,n)*Delta(R)' +

4*G(inf)*Delta(R,n+1/2)*Delta(strain,n+1/2)*Delta(R,n+1/2)'

- Pressure Term

P(n+1) = P(n)**1* + 2*K*trace(Delta(strain,n+1/2))**1*

where,

Delta(R), Delta(R,n+1/2) are given expressions in section 4.8.6

G(inf) is shear modulus at infinite time

Delta(train,n+1/2) is the incremental strain at time step n+1/2, expression

given in section 4.8.6

trace(Delta(strain,n+1/2)) is the trace of the above matrix

*1* is a unit matrix r identity tensor.

Please share whatever you feel. I will be of help and thanks in advance.