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calculate different strain tensors

This commit is contained in:
Martin Diehl 2019-09-30 14:28:58 -07:00
parent 0e3b09adc1
commit e96eb55edd
1 changed files with 13 additions and 6 deletions
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19
python/damask/dadf5.py
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@ -554,7 +554,7 @@ class DADF5():
self.__add_generic_pointwise(calculation,requested,pass_through)
def add_strain_tensor(self,t,ord,defgrad='F'): #ToDo: Use t and ord
def add_strain_tensor(self,t,ord,defgrad='F'):
"""
Adds the a strain tensor.
@ -570,21 +570,28 @@ class DADF5():
'V#Green':lambda V: np.broadcast_to(np.ones(3),[V.shape[0],3]) - 1.0/V**2,
'U#Green':lambda U: U**2 - np.broadcast_to(np.ones(3),[U.shape[0],3]),
}
if t.lower() in ['l','left']:
stretch = 'V'
elif t.lower() in ['r','right']:
stretch = 'U'
else:
raise KeyError
(U,S,Vh) = np.linalg.svd(defgrad['data']) # singular value decomposition
R_inv = np.transpose(np.matmul(U,Vh),(0,2,1)) # transposed rotation of polar decomposition
U = np.matmul(R_inv,defgrad['data']) # F = RU
(D,V) = np.linalg.eigh((U+np.transpose(U,(0,2,1)))*.5) # eigen decomposition (of symmetric(ed) matrix)
s = np.matmul(R_inv,defgrad['data']) if stretch == 'U' else \
np.matmul(defgrad['data'],R_inv)
(D,V) = np.linalg.eigh((s+np.transpose(s,(0,2,1)))*.5) # eigen decomposition (of symmetric(ed) matrix)
d = operator['V#ln'](D)
d = operator[stretch+'#'+{0:'ln',1:'Biot',2:'Green'}[ord]](D)
a = np.matmul(V,np.einsum('ij,ikj->ijk',d,V))
return {
'data' : a,
'label' : 'ln(V)({})'.format(defgrad['label']),
'label' : 'epsilon_{}^{}({})'.format(stretch,ord,defgrad['label']),
'meta' : {
'Unit' : defgrad['meta']['Unit'],
'Description' : 'Strain tensor ln(V){} ({})'.format(defgrad['label'],defgrad['meta']['Description']),
'Description' : 'Strain tensor of {} ({})'.format(defgrad['label'],defgrad['meta']['Description']),
'Creator' : 'dadf5.py:add_strain_tensor v{}'.format(version)
}
}