cratepy.material.materialoperations.first_piola_from_second_piola

first_piola_from_second_piola(def_gradient, second_piola_stress)[source]

First Piola-Kirchhoff from second Piola-Kirchhoff stress tensor.

\[\boldsymbol{P} = \boldsymbol{F} \boldsymbol{S}\]

where \(\boldsymbol{P}\) is the first Piola-Kirchhoff stress tensor and \(\boldsymbol{S}\) is the second Piola-Kirchhoff stress tensor.


Parameters:
  • def_gradient (numpy.ndarray (2d)) – Deformation gradient.

  • second_piola_stress (numpy.ndarray (2d)) – Second Piola-Kirchhoff stress tensor.

Returns:

first_piola_stress – First Piola-Kirchhoff stress tensor.

Return type:

numpy.ndarray (2d)