// verify settings and some initial calculations
const char *Neohookean::VerifyAndLoadProperties(int np)
{
// must enter G1 and Kbulk OR Etens and nu
if(G>=0. && Kbulk>=0.)
{ if(Etens>=0. || nu>=-1. || Lame>=0.)
return "Neohookean Hyperelastic material needs K and G, Lame and G, OR E and nu";
Etens = 9.*Kbulk*G/(3.*Kbulk+G);
nu = (3.*Kbulk-2.*G)/(6.*Kbulk+2.*G);
Lame = Kbulk - 2.*G/3.;
}
else if(G>=0. || Lame>=0.)
{ if(Etens>=0. || nu>=-1. || Kbulk>=0.)
return "Neohookean Hyperelastic material needs K and G, Lame and G, OR E and nu";
Kbulk = Lame + 2.*G/3.;
Etens = 9.*Kbulk*G/(3.*Kbulk+G);
nu = (3.*Kbulk-2.*G)/(6.*Kbulk+2.*G);
}
else if(Etens>=0 && G<0. && Lame<0. && Kbulk<0.)
{ // has Etens and nu
if(nu>0.5 || nu<-1.)
return "Neohookean Hyperelastic material needs K and G, Lame and G, OR E and nu (with nu between -1 and 1/2)";
G = Etens/(2.*(1.+nu));
// bulk modulus, but allow membrane to be incompressible
if(nu<0.5)
{ Kbulk = Etens/(3.*(1-2.*nu));
Lame = nu*Etens/(1.+nu)/(1.-2.*nu);
}
else if(MaterialStyle()!=MEMBRANE_MAT)
return "Neohookean Hyperelastic Poisson's ratio for solid material must be less than 1/2";
else
{ Kbulk = 0.; // whcih causes Cp-Cv=0 as well
Lame = 0.;
}
}
else
return "Neohookean Hyperelastic material needs K and G, Lame and G, OR E and nu";
if(UofJOption<HALF_J_SQUARED_MINUS_1_MINUS_LN_J && UofJOption>LN_J_SQUARED)
return "Neohookean dilational energy (UJOption) must be 0, 1, or 2";
// Convert to specific units (F/L^2 L^3/mass)
pr.Gsp = G/rho;
pr.Lamesp = Lame/rho;
pr.Ksp = pr.Lamesp + 2.*pr.Gsp/3.;
// heating gamma0
double alphaV = 3.e-6*aI;
gamma0 = Kbulk*alphaV/(rho*heatCapacity);
// call super class
return HyperElastic::VerifyAndLoadProperties(np);
}
// verify settings and some initial calculations
const char *Mooney::VerifyAndLoadProperties(int np)
{
// must enter G1 and Kbulk OR Etens and nu
if(G1>=0. && Kbulk>=0.)
{ if(Etens>=0. || nu>=-1.)
return "Mooney-Rivlin Hyperelastic material needs K and G1 OR E and nu";
Etens = 9.*Kbulk*G1/(3.*Kbulk+G1);
nu = (3.*Kbulk-2.*G1)/(6.*Kbulk+2.*G1);
}
else if(G1>=0. || Kbulk>=0. || Etens<0. || nu<-1.)
{ return "Mooney-Rivlin Hyperelastic material needs K and G1 OR E and nu";
}
else
{ // has Etens and nu
if(nu>0.5)
return "Mooney-Rivlin Hyperelastic Poisson's ratio must be between -1 and 1/2";
// get G1+G2 equal to low strain shear modulus
G1 = Etens/(2.*(1.+nu)) - G2;
// bulk modulus, but allow membrane to be incompressible
if(nu<0.5)
Kbulk = Etens/(3.*(1-2.*nu));
else if(MaterialStyle()!=MEMBRANE_MAT)
return "Mooney-Rivlin Hyperelastic Poisson's ratio for solid material must be less than 1/2";
else
{ Kbulk = 0.; // which causes CP-Cv=0 as well
}
}
if(G2<0.)
return "Mooney-Rivlin Hyperelastic material needs non-negative G2";
if(UofJOption<HALF_J_SQUARED_MINUS_1_MINUS_LN_J && UofJOption>LN_J_SQUARED)
return "Mooney-Rivlin dilational energy (UJOption) must be 0, 1, or 2";
// G1 and G2 in Specific units using initial rho (F/L^2 L^3/mass)
G1sp=G1/rho;
G2sp=G2/rho;
// heating gamma0 (dimensionless)
double alphaV = 3.e-6*aI;
gamma0 = Kbulk*alphaV/(rho*heatCapacity);
// call super class
return HyperElastic::VerifyAndLoadProperties(np);
}
