strain calculation agrees up to 1e-4 with results from addStrainTensors.
Not too exciting, but ok
This commit is contained in:
Martin Diehl 2019-09-13 19:18:41 -07:00
parent 38f6609ad7
commit 69462f8190
1 changed files with 17 additions and 16 deletions

View File

@ -81,7 +81,7 @@ class DADF5():
self.active[t] = list(existing.add(valid)) self.active[t] = list(existing.add(valid))
def __on_air_del(self,output): def __on_air_del(self,output,t):
choice = [output] if isinstance(output,str) else output choice = [output] if isinstance(output,str) else output
existing = set(self.active[t]) existing = set(self.active[t])
self.active[t] = list(existing.remove(choice)) self.active[t] = list(existing.remove(choice))
@ -275,7 +275,7 @@ class DADF5():
""" """
def Cauchy(F,P): def Cauchy(F,P):
sigma = np.einsum('i,ijk,ilk->ijl',1.0/np.linalg.det(F['data']),P['data'],F['data']) sigma = np.einsum('i,ijk,ilk->ijl',1.0/np.linalg.det(F['data']),P['data'],F['data'])
sigma = (sigma + np.einsum('ijk->ikj',sigma))*0.5 # enforce symmetry sigma = (sigma + np.einsum('ikj',sigma))*0.5 # enforce symmetry
return { return {
'data' : sigma, 'data' : sigma,
'label' : 'sigma', 'label' : 'sigma',
@ -294,10 +294,10 @@ class DADF5():
def add_Mises(self,x): def add_Mises(self,x):
"""Adds the equivalent Mises stres of a tensor.""" """Adds the equivalent Mises stress or strain of a tensor."""
def deviator(x): def deviator(x):
if x['meta']['Unit'] == 'Pa': if x['meta']['Unit'] == 'Pa': #ToDo: Should we use this? Then add_Cauchy and add_strain_tensors also should perform sanity checks
factor = 3.0/2.0 factor = 3.0/2.0
elif x['meta']['Unit'] == '-': elif x['meta']['Unit'] == '-':
factor = 2.0/3.0 factor = 2.0/3.0
@ -306,10 +306,10 @@ class DADF5():
d = x['data'] d = x['data']
dev = d - np.einsum('ijk,i->ijk',np.broadcast_to(np.eye(3),[d.shape[0],3,3]),np.trace(d,axis1=1,axis2=2)/3.0) dev = d - np.einsum('ijk,i->ijk',np.broadcast_to(np.eye(3),[d.shape[0],3,3]),np.trace(d,axis1=1,axis2=2)/3.0)
dev_sym = (dev + np.einsum('ikj',dev))*0.5 #dev_sym = (dev + np.einsum('ikj',dev))*0.5 # ToDo: this is not needed (only if the input is not symmetric, but then the whole concept breaks down)
return { return {
'data' : np.sqrt(np.einsum('ijk->i',dev_sym**2)*factor), 'data' : np.sqrt(np.einsum('ijk->i',dev**2)*factor),
'label' : 'dev({})'.format(x['label']), 'label' : 'dev({})'.format(x['label']),
'meta' : { 'meta' : {
'Unit' : x['meta']['Unit'], 'Unit' : x['meta']['Unit'],
@ -348,7 +348,7 @@ class DADF5():
'label' : 'norm({})'.format(x['label']), 'label' : 'norm({})'.format(x['label']),
'meta' : { 'meta' : {
'Unit' : x['meta']['Unit'], 'Unit' : x['meta']['Unit'],
'Description' : 'Norm of {} {} ({})'.format(t,x['label'],x['meta']['Description']), 'Description' : 'Norm of {} {} ({})'.format(t,x['label'],x['meta']['Description']), # ToDo: add details about norm used
'Creator' : 'dadf5.py:add_norm vXXXXX' 'Creator' : 'dadf5.py:add_norm vXXXXX'
} }
} }
@ -403,6 +403,10 @@ class DADF5():
"""Adds the deviator of a tensor.""" """Adds the deviator of a tensor."""
def deviator(x): def deviator(x):
d = x['data'] d = x['data']
if not np.all(np.array(d.shape[1:]) == np.array([3,3])):
raise ValueError
return { return {
'data' : d - np.einsum('ijk,i->ijk',np.broadcast_to(np.eye(3),[d.shape[0],3,3]),np.trace(d,axis1=1,axis2=2)/3.0), 'data' : d - np.einsum('ijk,i->ijk',np.broadcast_to(np.eye(3),[d.shape[0],3,3]),np.trace(d,axis1=1,axis2=2)/3.0),
'label' : 'dev({})'.format(x['label']), 'label' : 'dev({})'.format(x['label']),
@ -418,11 +422,11 @@ class DADF5():
self.__add_generic_pointwise(deviator,requested) self.__add_generic_pointwise(deviator,requested)
def add_strain_tensor(self,t,ord,defgrad='F'): def add_strain_tensor(self,t,ord,defgrad='F'): #ToDo: Use t and ord
"""Adds the a strain tensor.""" """Adds the a strain tensor."""
def strain_tensor(defgrad,t,ord): def strain_tensor(defgrad,t,ord):
(U,S,Vh) = np.linalg.svd(defgrad['data']) # singular value decomposition (U,S,Vh) = np.linalg.svd(defgrad['data']) # singular value decomposition
R_inv = np.einsum('ijk->ikj',np.matmul(U,Vh)) # inverse rotation of polar decomposition R_inv = np.einsum('ikj',np.matmul(U,Vh)) # inverse rotation of polar decomposition
U = np.matmul(R_inv,defgrad['data']) # F = RU U = np.matmul(R_inv,defgrad['data']) # F = RU
(D,V) = np.linalg.eigh((U+np.einsum('ikj',U))*.5) # eigen decomposition (of symmetric(ed) matrix) (D,V) = np.linalg.eigh((U+np.einsum('ikj',U))*.5) # eigen decomposition (of symmetric(ed) matrix)
@ -431,17 +435,14 @@ class DADF5():
V[neg[0],:,neg[1]] = V[neg[0],:,neg[1]]* -1 # ... and vector V[neg[0],:,neg[1]] = V[neg[0],:,neg[1]]* -1 # ... and vector
d = np.log(D) d = np.log(D)
a = np.matmul(V,np.einsum('ij,ikj->ijk',d,V)) # this is wrong ... a = np.matmul(V,np.einsum('ij,ikj->ijk',d,V))
for j in range(V.shape[0]): # but this is slow ...
a[j,:,:] = np.dot(V[j,:,:],np.dot(np.diag(d[j,:]),V[j,:,:].T))
print(np.max(a))
return { return {
'data' : a, 'data' : a,
'label' : 'lnV({})'.format(defgrad['label']), 'label' : 'ln(V)({})'.format(defgrad['label']),
'meta' : { 'meta' : {
'Unit' : defgrad['meta']['Unit'], 'Unit' : defgrad['meta']['Unit'],
'Description' : 'Strain tensor {} ({})'.format(defgrad['label'],defgrad['meta']['Description']), 'Description' : 'Strain tensor ln(V){} ({})'.format(defgrad['label'],defgrad['meta']['Description']),
'Creator' : 'dadf5.py:add_deviator vXXXXX' 'Creator' : 'dadf5.py:add_deviator vXXXXX'
} }
} }