def directional_poisson_ratio(self, n, m, tol=1e-8):
"""
Calculates the poisson ratio for a specific direction
relative to a second, orthogonal direction
Args:
n (3-d vector): principal direction
m (3-d vector): secondary direction orthogonal to n
tol (float): tolerance for testing of orthogonality
"""
n, m = get_uvec(n), get_uvec(m)
if not np.abs(np.dot(n, m)) < tol:
raise ValueError("n and m must be orthogonal")
v = self.compliance_tensor.einsum_sequence([n] * 2 + [m] * 2)
v *= -1 / self.compliance_tensor.einsum_sequence([n] * 4)
return v
def directional_poisson_ratio(self, n, m, tol=1e-8):
"""
Calculates the poisson ratio for a specific direction
relative to a second, orthogonal direction
Args:
n (3-d vector): principal direction
m (3-d vector): secondary direction orthogonal to n
tol (float): tolerance for testing of orthogonality
"""
n, m = get_uvec(n), get_uvec(m)
if not np.abs(np.dot(n, m)) < tol:
raise ValueError("n and m must be orthogonal")
v = self.compliance_tensor.einsum_sequence([n]*2 + [m]*2)
v *= -1 / self.compliance_tensor.einsum_sequence([n]*4)
return v
def get_stability_criteria(self, s, n):
"""
Gets the stability criteria from the symmetric
Wallace tensor from an input vector and stress
value.
Args:
s (float): Stress value at which to evaluate
the stability criteria
n (3x1 array-like): direction of the applied
stress
"""
n = get_uvec(n)
stress = s * np.outer(n, n)
sym_wallace = self.get_symmetric_wallace_tensor(stress)
return np.linalg.det(sym_wallace.voigt)
def get_stability_criteria(self, s, n):
"""
Gets the stability criteria from the symmetric
Wallace tensor from an input vector and stress
value.
Args:
s (float): Stress value at which to evaluate
the stability criteria
n (3x1 array-like): direction of the applied
stress
"""
n = get_uvec(n)
stress = s * np.outer(n, n)
sym_wallace = self.get_symmetric_wallace_tensor(stress)
return np.linalg.det(sym_wallace.voigt)
def directional_elastic_mod(self, n):
"""
Calculates directional elastic modulus for a specific vector
"""
n = get_uvec(n)
return self.einsum_sequence([n] * 4)
def directional_elastic_mod(self, n):
"""
Calculates directional elastic modulus for a specific vector
"""
n = get_uvec(n)
return self.einsum_sequence([n]*4)
