#[cfg(test)]
mod test;
use crate::{
constitutive::{
ConstitutiveError,
solid::{FIVE_THIRDS, Solid, TWO_THIRDS, elastic::Elastic, hyperelastic::Hyperelastic},
},
math::{IDENTITY, Quantity, Rank2, TensorRank4},
mechanics::{CauchyStress, CauchyTangentStiffness, Deformation, DeformationGradient, Scalar},
units::{EnergyDensity, Stress},
};
const FOUR_THIRDS: Scalar = 4.0 / 3.0;
#[doc = include_str!("doc.md")]
#[derive(Clone, Debug)]
pub struct Carroll {
pub bulk_modulus: Quantity<Stress>,
pub linear_modulus: Quantity<Stress>,
pub quartic_modulus: Quantity<Stress>,
pub second_invariant_modulus: Quantity<Stress>,
}
impl Carroll {
pub fn quartic_modulus(&self) -> Quantity<Stress> {
self.quartic_modulus
}
pub fn second_invariant_modulus(&self) -> Quantity<Stress> {
self.second_invariant_modulus
}
}
impl Solid for Carroll {
fn bulk_modulus(&self) -> Quantity<Stress> {
self.bulk_modulus
}
fn shear_modulus(&self) -> Quantity<Stress> {
self.linear_modulus * 2.0
+ self.quartic_modulus * 216.0
+ self.second_invariant_modulus / 3.0_f64.sqrt()
}
}
impl Elastic for Carroll {
#[doc = include_str!("cauchy_stress.md")]
fn cauchy_stress(
&self,
deformation_gradient: &DeformationGradient,
) -> Result<CauchyStress, ConstitutiveError> {
let jacobian = self.jacobian(deformation_gradient)?;
let isochoric_left_cauchy_green_deformation =
deformation_gradient.left_cauchy_green() / jacobian.powf(TWO_THIRDS);
let first_invariant = isochoric_left_cauchy_green_deformation.trace();
let second_invariant = isochoric_left_cauchy_green_deformation.second_invariant();
let dw_di1 = self.linear_modulus + self.quartic_modulus * (4.0 * first_invariant.powi(3));
let dw_di2 = self.second_invariant_modulus / (2.0 * second_invariant.sqrt());
Ok(
((isochoric_left_cauchy_green_deformation.deviatoric() * (dw_di1 * 2.0)
- isochoric_left_cauchy_green_deformation
.inverse()
.deviatoric()
* (dw_di2 * 2.0))
+ IDENTITY * (self.bulk_modulus() * 0.5 * (jacobian.powi(2) - 1.0)))
/ jacobian,
)
}
#[doc = include_str!("cauchy_tangent_stiffness.md")]
fn cauchy_tangent_stiffness(
&self,
deformation_gradient: &DeformationGradient,
) -> Result<CauchyTangentStiffness, ConstitutiveError> {
let jacobian = self.jacobian(deformation_gradient)?;
let inverse_transpose_deformation_gradient = deformation_gradient.inverse_transpose();
let isochoric_left_cauchy_green_deformation =
deformation_gradient.left_cauchy_green() / jacobian.powf(TWO_THIRDS);
let first_invariant = isochoric_left_cauchy_green_deformation.trace();
let second_invariant = isochoric_left_cauchy_green_deformation.second_invariant();
let dw_di1 = self.linear_modulus + self.quartic_modulus * (4.0 * first_invariant.powi(3));
let dw_di2 = self.second_invariant_modulus / (2.0 * second_invariant.sqrt());
let scaled_dw_di1 = dw_di1 * 2.0 / jacobian.powf(FIVE_THIRDS);
let inverse_isochoric_left_cauchy_green_deformation =
isochoric_left_cauchy_green_deformation.inverse();
let deviatoric_inverse_isochoric_left_cauchy_green_deformation =
inverse_isochoric_left_cauchy_green_deformation.deviatoric();
let term_1 = TensorRank4::dyad_ij_kl(
&inverse_isochoric_left_cauchy_green_deformation,
&inverse_transpose_deformation_gradient,
) * TWO_THIRDS
- TensorRank4::dyad_ik_jl(
&inverse_isochoric_left_cauchy_green_deformation,
&inverse_transpose_deformation_gradient,
)
- TensorRank4::dyad_il_jk(
&inverse_transpose_deformation_gradient,
&inverse_isochoric_left_cauchy_green_deformation,
);
let term_3 = TensorRank4::dyad_ij_kl(
&deviatoric_inverse_isochoric_left_cauchy_green_deformation,
&inverse_transpose_deformation_gradient,
);
let term_2 = TensorRank4::dyad_ij_kl(
&IDENTITY,
&((deviatoric_inverse_isochoric_left_cauchy_green_deformation.clone() * TWO_THIRDS)
* &inverse_transpose_deformation_gradient),
);
let d_first_invariant_dw_di1_df = deformation_gradient
* (48.0 * self.quartic_modulus * first_invariant.powi(2) / jacobian.powf(TWO_THIRDS))
- inverse_transpose_deformation_gradient.clone()
* (16.0 * self.quartic_modulus * first_invariant.powi(3));
let identity_i1_minus_b =
IDENTITY * first_invariant - isochoric_left_cauchy_green_deformation.clone();
let d_second_invariant_dw_di2_df = (identity_i1_minus_b * deformation_gradient)
* (-2.0 * dw_di2 / second_invariant / jacobian.powf(TWO_THIRDS))
+ inverse_transpose_deformation_gradient.clone() * (dw_di2 * FOUR_THIRDS);
let extra_term_1 = TensorRank4::dyad_ij_kl(
&isochoric_left_cauchy_green_deformation.deviatoric(),
&d_first_invariant_dw_di1_df,
) / jacobian;
let extra_term_2 = TensorRank4::dyad_ij_kl(
&deviatoric_inverse_isochoric_left_cauchy_green_deformation,
&d_second_invariant_dw_di2_df,
) / jacobian;
Ok((TensorRank4::dyad_ik_jl(&IDENTITY, deformation_gradient)
+ TensorRank4::dyad_il_jk(deformation_gradient, &IDENTITY)
- TensorRank4::dyad_ij_kl(&IDENTITY, deformation_gradient) * (TWO_THIRDS))
* scaled_dw_di1
+ TensorRank4::dyad_ij_kl(
&(IDENTITY * (0.5 * self.bulk_modulus() * (jacobian + 1.0 / jacobian))
- deformation_gradient.left_cauchy_green().deviatoric()
* (scaled_dw_di1 * FIVE_THIRDS)),
&inverse_transpose_deformation_gradient,
)
- (term_1 + term_2 - term_3) * (dw_di2 * 2.0) / jacobian
+ extra_term_1
- extra_term_2)
}
}
impl Hyperelastic for Carroll {
#[doc = include_str!("helmholtz_free_energy_density.md")]
fn helmholtz_free_energy_density(
&self,
deformation_gradient: &DeformationGradient,
) -> Result<Quantity<EnergyDensity>, ConstitutiveError> {
let jacobian = self.jacobian(deformation_gradient)?;
let isochoric_left_cauchy_green_deformation =
deformation_gradient.left_cauchy_green() / jacobian.powf(TWO_THIRDS);
let first_invariant = isochoric_left_cauchy_green_deformation.trace();
let second_invariant = isochoric_left_cauchy_green_deformation.second_invariant();
Ok(self.linear_modulus * (first_invariant - 3.0)
+ self.quartic_modulus * (first_invariant.powi(4) - 81.0)
+ self.second_invariant_modulus * (second_invariant.sqrt() - 3.0_f64.sqrt())
+ self.bulk_modulus() * (0.5 * (jacobian.powi(2) - 1.0) - jacobian.ln()) * 0.5)
}
}