FEM: CLOAD, mesh face area is used for surface loads on volume faces
This commit is contained in:
Bernd Hahnebach
wmayer
parent
81bd2cf34a
commit
3c629f095d
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@ -29,7 +29,7 @@ class inp_writer:
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self.write_step_begin(inpfile)
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self.write_constraints_fixed(inpfile)
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self.write_constraints_force(inpfile)
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self.write_face_load(inpfile)
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#self.write_face_load(inpfile)
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self.write_outputs_types(inpfile)
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self.write_step_end(inpfile)
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self.write_footer(inpfile)
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@ -155,12 +155,17 @@ class inp_writer:
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f.write(fix_obj_name + ',3\n\n')
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def write_constraints_force(self, f):
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def getTriangleArea(P1,P2,P3):
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vec1 = P2 - P1
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vec2 = P3 - P1
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vec3 = vec1.cross(vec2)
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return 0.5 * vec3.Length
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f.write('\n***********************************************************\n')
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f.write('** Node loads, see load node sets for how the value is calculated!\n')
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f.write('** Node loads\n')
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f.write('** written by {} function\n'.format(sys._getframe().f_code.co_name))
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for fobj in self.force_objects:
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frc_obj = fobj['Object']
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if 'NodeLoad' in fobj:
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frc_obj = fobj['Object']
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node_load = fobj['NodeLoad']
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frc_obj_name = frc_obj.Name
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vec = frc_obj.DirectionVector
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@ -173,6 +178,130 @@ class inp_writer:
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f.write(frc_obj_name + ',2,' + v2 + '\n')
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f.write(frc_obj_name + ',3,' + v3 + '\n\n')
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# area load on faces of volume elements --> CLOAD is used
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sum_ref_face_area = 0
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sum_ref_face_node_area = 0
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sum_node_load = 0
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for o, elem in frc_obj.References:
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elem_o = o.Shape.getElement(elem)
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if elem_o.ShapeType == 'Face':
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sum_ref_face_area += elem_o.Area
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if sum_ref_face_area != 0:
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print frc_obj.Name, ', AreaLoad on faces, CLOAD is used'
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force_per_sum_ref_face_area = frc_obj.Force / sum_ref_face_area
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print ' force_per_sum_ref_face_area: ', force_per_sum_ref_face_area
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for o, elem in frc_obj.References:
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elem_o = o.Shape.getElement(elem)
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if elem_o.ShapeType == 'Face':
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ref_face = elem_o
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print ' ', o.Name, '.', elem,
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f.write('** ' + frc_obj.Name + '\n')
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f.write('*CLOAD\n')
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f.write('** node loads on element face: ' + o.Name + '.' + elem + '\n')
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volume_faces = self.mesh_object.FemMesh.getVolumesByFace(ref_face)
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face_table = {} # { meshfaceID : ( nodeID, ... , nodeID ) }
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for mv,mf in volume_faces:
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face_table[mf] = self.mesh_object.FemMesh.getElementNodes(mf)
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# calulate the appropriate node_areas for every node of every mesh face (mf)
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# G. Lakshmi Narasaiah, Finite Element Analysis, p206ff
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node_area_table = [] # [ (nodeID,Area), ... , (nodeID,Area) ] some nodes will have more than one entries
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node_sumarea_table = {} # { nodeID : Area, ... , nodeID:Area } AreaSum for each node, one entry for each node
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mesh_face_area = 0
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for mf in face_table:
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# print ' ', mf, ' --> ', face_table[mf]
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if len(face_table[mf]) == 3: # 3 node mesh face triangle
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# corner_node_area = mesh_face_area / 3.0
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# P3
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# /\
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# / \
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# /____\
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# P1 P2
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P1 = self.mesh_object.FemMesh.Nodes[face_table[mf][0]]
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P2 = self.mesh_object.FemMesh.Nodes[face_table[mf][1]]
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P3 = self.mesh_object.FemMesh.Nodes[face_table[mf][2]]
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mesh_face_area = getTriangleArea(P1,P2,P3)
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corner_node_area = mesh_face_area / 3.0
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node_area_table.append((face_table[mf][0], corner_node_area))
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node_area_table.append((face_table[mf][1], corner_node_area))
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node_area_table.append((face_table[mf][2], corner_node_area))
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if len(face_table[mf]) == 6: # 6 node mesh face triangle
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# corner_node_area = 0
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# middle_node_area = mesh_face_area / 3.0
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# P3
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# /\
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# /t3\
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# / \
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# P6------P5
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# / \ t4 / \
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# /t1 \ /t2 \
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# /_____\/_____\
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# P1 P4 P2
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P1 = self.mesh_object.FemMesh.Nodes[face_table[mf][0]]
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P2 = self.mesh_object.FemMesh.Nodes[face_table[mf][1]]
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P3 = self.mesh_object.FemMesh.Nodes[face_table[mf][2]]
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P4 = self.mesh_object.FemMesh.Nodes[face_table[mf][3]]
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P5 = self.mesh_object.FemMesh.Nodes[face_table[mf][4]]
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P6 = self.mesh_object.FemMesh.Nodes[face_table[mf][5]]
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mesh_face_t1_area = getTriangleArea(P1,P4,P6)
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mesh_face_t2_area = getTriangleArea(P2,P5,P4)
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mesh_face_t3_area = getTriangleArea(P3,P6,P5)
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mesh_face_t4_area = getTriangleArea(P4,P5,P6)
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mesh_face_area = mesh_face_t1_area + mesh_face_t2_area + mesh_face_t3_area + mesh_face_t4_area
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middle_node_area = mesh_face_area / 3.0
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node_area_table.append((face_table[mf][0], 0))
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node_area_table.append((face_table[mf][1], 0))
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node_area_table.append((face_table[mf][2], 0))
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node_area_table.append((face_table[mf][3], middle_node_area))
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node_area_table.append((face_table[mf][4], middle_node_area))
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node_area_table.append((face_table[mf][5], middle_node_area))
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# node_sumarea_table
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for n, A in node_area_table:
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# print n, ' --> ', A
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if n in node_sumarea_table:
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node_sumarea_table[n] = node_sumarea_table[n] + A
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else:
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node_sumarea_table[n] = A
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sum_node_areas = 0
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for n in node_sumarea_table:
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# print n, ' --> ', node_sumarea_table[n]
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sum_node_areas = sum_node_areas + node_sumarea_table[n]
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print ' sum_node_areas ', sum_node_areas, ' ref_face.Area: ', ref_face.Area
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sum_ref_face_node_area += sum_node_areas
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# write CLOAD lines to CalculiX file
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vec = frc_obj.DirectionVector
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for n in sorted(node_sumarea_table):
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node_load = node_sumarea_table[n] * force_per_sum_ref_face_area
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sum_node_load += node_load
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#print ' nodeID: ', n, ' nodeload: ', node_load
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if (vec.x != 0.0):
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v1 = "{:.13E}".format(vec.x * node_load)
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f.write(str(n) + ',1,' + v1 + '\n')
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if (vec.y != 0.0):
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v2 = "{:.13E}".format(vec.y * node_load)
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f.write(str(n) + ',2,' + v2 + '\n')
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if (vec.z != 0.0):
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v3 = "{:.13E}".format(vec.z * node_load)
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f.write(str(n) + ',3,' + v3 + '\n')
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f.write('\n')
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# print ' sum_ref_face_node_area: ', sum_ref_face_node_area
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# print ' sum_ref_face_area : ', sum_ref_face_area
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# print ' sum_ref_face_node_area * force_per_sum_ref_face_area: ', sum_ref_face_node_area * force_per_sum_ref_face_area
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# print ' sum_node_load: ', sum_node_load
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# print ' frc_obj.Force: ', frc_obj.Force
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f.write('\n')
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def write_face_load(self, f):
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f.write('\n***********************************************************\n')
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f.write('** Element + CalculiX face + load in [MPa]\n')
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