Function hookes_law_kernel 

pub fn hookes_law_kernel(
    stiffness: &CausalTensor<f64>,
    strain: &CausalTensor<f64>,
) -> Result<CausalTensor<f64>, PhysicsError>

Calculates generalized Hooke’s Law: $\sigma_{ij} = C_{ijkl} \epsilon_{kl}$.

Computes stress tensor from stiffness tensor (Rank 4) and strain tensor (Rank 2) via Einstein Summation.

Arguments

• stiffness - Stiffness tensor $C$ (Rank 4).
• strain - Strain tensor $\epsilon$ (Rank 2).

Returns

• Ok(CausalTensor<f64>) - Stress tensor $\sigma$ (Rank 2).