suzanne.soy/FreeCAD
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

FEM: ConstraintForce: add node load calculation for face loads on quad4 and quad8 faces

Browse Source
This commit is contained in:
Bernd Hahnebach 2016-09-01 09:34:49 +02:00
parent 3d4905824f
commit 781bd43667
1 changed files with 64 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
src/Mod/Fem/FemMeshTools.py
View File

@ -443,6 +443,7 @@ def get_ref_facenodes_areas(femnodes_mesh, face_table):
# FIXME only gives exact results in case of a real triangle. If for S6 or C3D10 elements
# the midnodes are not on the line between the end nodes the area will not be a triangle
# see http://forum.freecadweb.org/viewtopic.php?f=18&t=10939&start=40#p91355 and ff
# same applies for the quads, results are exact only if mid nodes are on the line between corner nodes
# [ (nodeID,Area), ... , (nodeID,Area) ] some nodes will have more than one entry
if (not femnodes_mesh) or (not face_table):
@ -471,7 +472,29 @@ def get_ref_facenodes_areas(femnodes_mesh, face_table):
node_area_table.append((face_table[mf][2], corner_node_area))
elif femmesh_facetype == 4: # 4 node femmesh face quad
FreeCAD.Console.PrintError('Face load on 4 node quad faces are not supported\n')
# corner_node_area = mesh_face_area / 4.0
# P4_______P3
# | /|
# | t2 / |
# | / |
# | / |
# | / t1 |
# |/_____|
# P1 P2
P1 = femnodes_mesh[face_table[mf][0]]
P2 = femnodes_mesh[face_table[mf][1]]
P3 = femnodes_mesh[face_table[mf][2]]
P4 = femnodes_mesh[face_table[mf][3]]
mesh_face_t1_area = get_triangle_area(P1, P2, P3)
mesh_face_t2_area = get_triangle_area(P1, P3, P4)
mesh_face_area = mesh_face_t1_area + mesh_face_t1_area
corner_node_area = mesh_face_area / 4.0
node_area_table.append((face_table[mf][0], corner_node_area))
node_area_table.append((face_table[mf][1], corner_node_area))
node_area_table.append((face_table[mf][2], corner_node_area))
node_area_table.append((face_table[mf][3], corner_node_area))
elif femmesh_facetype == 6: # 6 node femmesh face triangle
# corner_node_area = 0
@ -507,7 +530,46 @@ def get_ref_facenodes_areas(femnodes_mesh, face_table):
node_area_table.append((face_table[mf][5], middle_node_area))
elif femmesh_facetype == 8: # 8 node femmesh face quad
FreeCAD.Console.PrintError('Face load on 8 node quad faces are not supported\n')
# corner_node_area = -mesh_face_area / 12.0 (negativ!)
# mid-side nodes = mesh_face_area / 3.0
# P4_________P7________P3
# | / | \ |
# | t4 / | \ t3 |
# | / | \ |
# |/ | \|
# P8| t5 | t6 |P6
# |\ | / |
# | \ | / |
# | t1 \ | / t2 |
# |______\_|_/_______|
# P1 P5 P2
P1 = femnodes_mesh[face_table[mf][0]]
P2 = femnodes_mesh[face_table[mf][1]]
P3 = femnodes_mesh[face_table[mf][2]]
P4 = femnodes_mesh[face_table[mf][3]]
P5 = femnodes_mesh[face_table[mf][4]]
P6 = femnodes_mesh[face_table[mf][5]]
P7 = femnodes_mesh[face_table[mf][6]]
P8 = femnodes_mesh[face_table[mf][7]]
mesh_face_t1_area = get_triangle_area(P1, P5, P8)
mesh_face_t2_area = get_triangle_area(P5, P2, P6)
mesh_face_t3_area = get_triangle_area(P6, P3, P7)
mesh_face_t4_area = get_triangle_area(P7, P4, P8)
mesh_face_t5_area = get_triangle_area(P5, P7, P8)
mesh_face_t6_area = get_triangle_area(P5, P6, P7)
mesh_face_area = mesh_face_t1_area + mesh_face_t2_area + mesh_face_t3_area + mesh_face_t4_area + mesh_face_t5_area + mesh_face_t6_area
corner_node_area = -mesh_face_area / 12.0
middle_node_area = mesh_face_area / 3.0
node_area_table.append((face_table[mf][0], corner_node_area))
node_area_table.append((face_table[mf][1], corner_node_area))
node_area_table.append((face_table[mf][2], corner_node_area))
node_area_table.append((face_table[mf][3], corner_node_area))
node_area_table.append((face_table[mf][4], middle_node_area))
node_area_table.append((face_table[mf][5], middle_node_area))
node_area_table.append((face_table[mf][6], middle_node_area))
node_area_table.append((face_table[mf][7], middle_node_area))
return node_area_table