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:
pymatgen.core.tensors.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
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property
dev_principal_invariants
¶ 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
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property
deviator_stress
¶ returns the deviatoric component of the stress
-
property
mean_stress
¶ returns the mean stress
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piola_kirchoff_1
(def_grad)[source]¶ calculates the first Piola-Kirchoff stress
- Parameters
def_grad (3x3 array-like) – deformation gradient tensor
-
piola_kirchoff_2
(def_grad)[source]¶ calculates the second Piola-Kirchoff stress
- Parameters
def_grad (3x3 array-like) – rate of deformation tensor
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symbol
= 's'¶
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property
von_mises
¶ returns the von mises stress