conspire/constitutive/solid/hyperelastic/neo_hookean/
mod.rs

1#[cfg(test)]
2mod test;
3
4use crate::{
5    constitutive::{
6        Constitutive, ConstitutiveError, Parameters,
7        solid::{FIVE_THIRDS, Solid, TWO_THIRDS, elastic::Elastic, hyperelastic::Hyperelastic},
8    },
9    math::{IDENTITY, Rank2},
10    mechanics::{CauchyStress, CauchyTangentStiffness, Deformation, DeformationGradient, Scalar},
11};
12
13#[doc = include_str!("model.md")]
14#[derive(Debug)]
15pub struct NeoHookean<P> {
16    parameters: P,
17}
18
19impl<P> Constitutive<P> for NeoHookean<P>
20where
21    P: Parameters,
22{
23    fn new(parameters: P) -> Self {
24        Self { parameters }
25    }
26}
27
28impl<P> Solid for NeoHookean<P>
29where
30    P: Parameters,
31{
32    fn bulk_modulus(&self) -> &Scalar {
33        self.parameters.get(0)
34    }
35    fn shear_modulus(&self) -> &Scalar {
36        self.parameters.get(1)
37    }
38}
39
40impl<P> Elastic for NeoHookean<P>
41where
42    P: Parameters,
43{
44    #[doc = include_str!("cauchy_stress.md")]
45    fn cauchy_stress(
46        &self,
47        deformation_gradient: &DeformationGradient,
48    ) -> Result<CauchyStress, ConstitutiveError> {
49        let jacobian = self.jacobian(deformation_gradient)?;
50        Ok(
51            deformation_gradient.left_cauchy_green().deviatoric() / jacobian.powf(FIVE_THIRDS)
52                * self.shear_modulus()
53                + IDENTITY * self.bulk_modulus() * 0.5 * (jacobian - 1.0 / jacobian),
54        )
55    }
56    #[doc = include_str!("cauchy_tangent_stiffness.md")]
57    fn cauchy_tangent_stiffness(
58        &self,
59        deformation_gradient: &DeformationGradient,
60    ) -> Result<CauchyTangentStiffness, ConstitutiveError> {
61        let jacobian = self.jacobian(deformation_gradient)?;
62        let inverse_transpose_deformation_gradient = deformation_gradient.inverse_transpose();
63        let scaled_shear_modulus = self.shear_modulus() / jacobian.powf(FIVE_THIRDS);
64        Ok(
65            (CauchyTangentStiffness::dyad_ik_jl(&IDENTITY, deformation_gradient)
66                + CauchyTangentStiffness::dyad_il_jk(deformation_gradient, &IDENTITY)
67                - CauchyTangentStiffness::dyad_ij_kl(&IDENTITY, deformation_gradient)
68                    * (TWO_THIRDS))
69                * scaled_shear_modulus
70                + CauchyTangentStiffness::dyad_ij_kl(
71                    &(IDENTITY * (0.5 * self.bulk_modulus() * (jacobian + 1.0 / jacobian))
72                        - deformation_gradient.left_cauchy_green().deviatoric()
73                            * (scaled_shear_modulus * FIVE_THIRDS)),
74                    &inverse_transpose_deformation_gradient,
75                ),
76        )
77    }
78}
79
80impl<P> Hyperelastic for NeoHookean<P>
81where
82    P: Parameters,
83{
84    #[doc = include_str!("helmholtz_free_energy_density.md")]
85    fn helmholtz_free_energy_density(
86        &self,
87        deformation_gradient: &DeformationGradient,
88    ) -> Result<Scalar, ConstitutiveError> {
89        let jacobian = self.jacobian(deformation_gradient)?;
90        Ok(0.5
91            * (self.shear_modulus()
92                * (deformation_gradient.left_cauchy_green().trace() / jacobian.powf(TWO_THIRDS)
93                    - 3.0)
94                + self.bulk_modulus() * (0.5 * (jacobian.powi(2) - 1.0) - jacobian.ln())))
95    }
96}
conspire/constitutive/solid/hyperelastic/neo_hookean/mod.rs

conspire/constitutive/solid/hyperelastic/neo_hookean/
mod.rs
