def addFaceTraction(order, forest, attr, assembler, tr):
trac = []
for findex in range(6):
trac.append(elements.Traction3D(order, findex, tr[0], tr[1], tr[2]))
# Retrieve octants from the forest
octants = forest.getOctants()
face_octs = forest.getOctsWithAttribute(attr)
aux = TACS.AuxElements()
for i in range(len(face_octs)):
aux.addElement(face_octs[i].tag, trac[face_octs[i].info])
return aux
def compute3DTractionLoad(name, forest, assembler, tr):
"""
Add a constant surface traction to all octants that touch a face or edge with
the given name.
Args:
forest (QuadForest or OctForest): Forest for the finite-element mesh
name (str): Name of the surface where the traction will be added
assembler (Assembler): TACSAssembler object for the finite-element problem
tr (list): The 3D components of the traction.
Returns:
Vec: A force vector containing the traction
"""
order = forest.getMeshOrder()
trac = []
for findex in range(6):
trac.append(elements.Traction3D(order, findex, tr[0], tr[1], tr[2]))
return computeTractionLoad(name, forest, assembler, trac)
def createAssembler(tacs_comm):
# Set constitutive properties
rho = 4540.0 # density, kg/m^3
E = 118e9 # elastic modulus, Pa 118e9
nu = 0.325 # poisson's ratio
ys = 1050e6 # yield stress, Pa
kappa = 6.89
specific_heat = 463.0
# Set the back-pressure for the traction load
pb = 654.9 #10.0 # A value for the surface pressure
# Load in the mesh
mesh = TACS.MeshLoader(tacs_comm)
mesh.scanBDFFile('tacs_aero.bdf')
# Get the number of components set in the mesh. Each component is
num_components = mesh.getNumComponents()
# Each domain consists of the union of two components. The component
# corresponding to the surface traction and the component corresponding
# to remaining plate elements. There is one design variable associated
# with each domain that shares a common (x,z) coordinate
num_domains = num_components // 2
# Create the constitutvie propertes and model
props_plate = constitutive.MaterialProperties(rho=rho,
specific_heat=specific_heat,
kappp=kappa,
E=E,
nu=nu,
ys=ys)
# Create the basis class
basis = elements.LinearHexaBasis()
element_list = []
for k in range(num_domains):
# Create the elements in an element list
con = constitutive.SolidConstitutive(props_plate, t=1.0, tNum=k)
phys_model = elements.LinearThermoelasticity3D(con)
# Create the element
element_list.append(elements.Element3D(phys_model, basis))
varsPerNode = phys_model.getVarsPerNode()
# Set the face index for the side of the element where the traction
# will be applied. The face indices are as follows for the hexahedral
# basis class:
# -x: 0, +x: 1, -y: 2, +y: 3, -z: 4, +z: 5
faceIndex = 4
# Set the wedge angle - 5 degrees
theta = np.radians(5.0)
# Compute the outward normal components for the face
nx = np.sin(theta)
nz = -np.cos(theta)
# Set the traction components
tr = [-pb * nx, 0.0, -pb * nz, 0.0]
# Create the traction class
traction = elements.Traction3D(varsPerNode, faceIndex, basis, tr)
# Set the elements corresponding to each component number
num_components = mesh.getNumComponents()
for k in range(num_components):
mesh.setElement(k, element_list[k % num_domains])
# Create the assembler object
assembler = mesh.createTACS(varsPerNode)
# Set the traction load into the assembler object
aux = TACS.AuxElements(assembler)
for k in range(num_domains, num_components):
mesh.addAuxElement(aux, k, traction)
assembler.setAuxElements(aux)
return assembler, num_domains