pymatgen.analysis.elasticity.stress module
This module provides the Stress class used to create, manipulate, and calculate relevant properties of the stress tensor.
- class Stress(stress_matrix)[source]
Bases:
SquareTensor
This class extends SquareTensor as a representation of the stress
Create a Stress object. Note that the constructor uses __new__ rather than __init__ according to the standard method of subclassing numpy ndarrays.
- Parameters:
stress_matrix (3x3 array-like) – the 3x3 array-like representing the stress
- property dev_principal_invariants[source]
returns the principal invariants of the deviatoric stress tensor, which is calculated by finding the coefficients of the characteristic polynomial of the stress tensor minus the identity times the mean stress
- piola_kirchoff_1(def_grad)[source]
calculates the first Piola-Kirchoff stress
- Parameters:
def_grad (3x3 array-like) – deformation gradient tensor