FEM: Add rigid body constraint to ccx writer

src/Mod/Fem/CMakeLists.txt

@@ -225,6 +225,7 @@ SET(FemSolverCalculix_SRCS
     femsolver/calculix/write_constraint_initialtemperature.py
     femsolver/calculix/write_constraint_planerotation.py
     femsolver/calculix/write_constraint_pressure.py
+    femsolver/calculix/write_constraint_rigidbody.py
     femsolver/calculix/write_constraint_sectionprint.py
     femsolver/calculix/write_constraint_selfweight.py
     femsolver/calculix/write_constraint_temperature.py

src/Mod/Fem/ObjectsFem.py

@@ -158,6 +158,16 @@ def makeConstraintFixed(
     return obj
 
 
+def makeConstraintRigidBody(
+    doc,
+    name="ConstraintRigidBody"
+):
+    """makeConstraintRigidBody(document, [name]):
+    makes a Fem ConstraintRigidBody object"""
+    obj = doc.addObject("Fem::ConstraintRigidBody", name)
+    return obj
+
+
 def makeConstraintFlowVelocity(
     doc,
     name="ConstraintFlowVelocity"

src/Mod/Fem/femmesh/meshsetsgetter.py

@@ -139,6 +139,7 @@ def get_mesh_sets(self):
         # constraints node sets getter
         self.get_constraints_fixed_nodes()
         self.get_constraints_displacement_nodes()
+        self.get_constraints_rigidbody_nodes()
         self.get_constraints_planerotation_nodes()
 
         # constraints surface sets getter
@@ -205,6 +206,21 @@ def get_constraints_fixed_nodes(self):
                 femobj["NodesSolid"] = set(nds_solid)
                 femobj["NodesFaceEdge"] = set(nds_faceedge)
 
+    def get_constraints_rigidbody_nodes(self):
+        if not self.member.cons_rigidbody:
+            return
+        # get nodes
+        for femobj in self.member.cons_rigidbody:
+            # femobj --> dict, FreeCAD document object is femobj["Object"]
+            print_obj_info(femobj["Object"])
+            femobj["Nodes"] = meshtools.get_femnodes_by_femobj_with_references(
+                self.femmesh,
+                femobj
+            )
+            # add nodes to constraint_conflict_nodes, needed by constraint plane rotation
+            for node in femobj["Nodes"]:
+                self.constraint_conflict_nodes.append(node)
+
     def get_constraints_displacement_nodes(self):
         if not self.member.cons_displacement:
             return

src/Mod/Fem/femsolver/calculix/write_constraint_rigidbody.py

@@ -0,0 +1,105 @@
+# ***************************************************************************
+# *   Copyright (c) 2022 Ajinkya Dahale <dahale.a.p@gmail.com>              *
+# *                                                                         *
+# *   This file is part of the FreeCAD CAx development system.              *
+# *                                                                         *
+# *   This program is free software; you can redistribute it and/or modify  *
+# *   it under the terms of the GNU Lesser General Public License (LGPL)    *
+# *   as published by the Free Software Foundation; either version 2 of     *
+# *   the License, or (at your option) any later version.                   *
+# *   for detail see the LICENCE text file.                                 *
+# *                                                                         *
+# *   This program is distributed in the hope that it will be useful,       *
+# *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+# *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+# *   GNU Library General Public License for more details.                  *
+# *                                                                         *
+# *   You should have received a copy of the GNU Library General Public     *
+# *   License along with this program; if not, write to the Free Software   *
+# *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  *
+# *   USA                                                                   *
+# *                                                                         *
+# ***************************************************************************
+
+__title__ = "FreeCAD FEM calculix constraint rigid body"
+__author__ = "Ajinkya Dahale"
+__url__ = "https://www.freecadweb.org"
+
+
+def get_analysis_types():
+    return "all"    # write for all analysis types
+
+
+def get_sets_name():
+    return "constraints_rigidbody_node_sets"
+
+
+def get_constraint_title():
+    return "Rigid Body Constraints"
+
+
+def get_before_write_meshdata_constraint():
+    return ""
+
+
+def get_after_write_meshdata_constraint():
+    return ""
+
+
+def get_before_write_constraint():
+    return ""
+
+
+def get_after_write_constraint():
+    return ""
+
+
+def write_meshdata_constraint(f, femobj, rb_obj, ccxwriter):
+    f.write("*NSET,NSET=" + rb_obj.Name + "\n")
+    for n in femobj["Nodes"]:
+        f.write("{},\n".format(n))
+
+
+def write_constraint(f, femobj, rb_obj, ccxwriter):
+
+    # floats read from ccx should use {:.13G}, see comment in writer module
+    is_ref_bc_defined = any((rb_obj.xDisplacement,
+                             rb_obj.yDisplacement,
+                             rb_obj.zDisplacement,
+                             rb_obj.xLoad,
+                             rb_obj.yLoad,
+                             rb_obj.zLoad))
+
+    is_rot_bc_defined = any((rb_obj.xRotation,
+                             rb_obj.yRotation,
+                             rb_obj.zRotation,
+                             rb_obj.xMoment,
+                             rb_obj.yMoment,
+                             rb_obj.zMoment))
+
+    # FIXME: This needs to be implemented
+    ref_node_idx = -1
+    rot_node_idx = -1
+
+    kw_line = "*RIGID BODY,NSET={}".format(rb_obj.Name)
+
+    if is_ref_bc_defined:
+        kw_line = kw_line + ",REF NODE={}".format(ref_node_idx)
+
+    if is_rot_bc_defined:
+        kw_line = kw_line + ",ROT NODE={}".format(rot_node_idx)
+
+    f.write(kw_line + "\n")
+
+    # TODO: Displacement definitions need fixing
+    if is_ref_bc_defined:
+        f.write("*CLOAD\n")
+        f.write("{},1,{}\n".format(ref_node_idx, rb_obj.xLoad))
+        f.write("{},2,{}\n".format(ref_node_idx, rb_obj.yLoad))
+        f.write("{},3,{}\n".format(ref_node_idx, rb_obj.zLoad))
+
+    if is_rot_bc_defined:
+        f.write("*CLOAD\n")
+        f.write("{},1,{}\n".format(rot_node_idx, rb_obj.xMoment))
+        f.write("{},2,{}\n".format(rot_node_idx, rb_obj.yMoment))
+        f.write("{},3,{}\n".format(rot_node_idx, rb_obj.zMoment))

src/Mod/Fem/femsolver/calculix/writer.py

@@ -45,6 +45,7 @@
 from . import write_constraint_initialtemperature as con_itemp
 from . import write_constraint_planerotation as con_planerotation
 from . import write_constraint_pressure as con_pressure
+from . import write_constraint_rigidbody as con_rigidbody
 from . import write_constraint_sectionprint as con_sectionprint
 from . import write_constraint_selfweight as con_selfweight
 from . import write_constraint_temperature as con_temperature
@@ -161,6 +162,7 @@ def write_solver_input(self):
 
         # node sets
         self.write_constraints_meshsets(inpfile, self.member.cons_fixed, con_fixed)
+        self.write_constraints_meshsets(inpfile, self.member.cons_rigidbody, con_rigidbody)
         self.write_constraints_meshsets(inpfile, self.member.cons_displacement, con_displacement)
         self.write_constraints_meshsets(inpfile, self.member.cons_planerotation, con_planerotation)
         self.write_constraints_meshsets(inpfile, self.member.cons_transform, con_transform)
@@ -181,6 +183,7 @@ def write_solver_input(self):
         self.write_constraints_propdata(inpfile, self.member.cons_contact, con_contact)
         self.write_constraints_propdata(inpfile, self.member.cons_tie, con_tie)
         self.write_constraints_propdata(inpfile, self.member.cons_transform, con_transform)
+        self.write_constraints_propdata(inpfile, self.member.cons_rigidbody, con_rigidbody)
 
         # step equation
         write_step_equation.write_step_equation(inpfile, self)

src/Mod/Fem/femtools/membertools.py

@@ -204,6 +204,10 @@ def __init__(self, analysis):
             list of fixed constraints from the analysis.
             [{"Object":fixed_obj, "NodeSupports":bool}, {}, ...]
 
+        constraints_rigidbody : list of dictionaries
+            list of displacements for the analysis.
+            [{"Object":rigidbody_obj, "xxxxxxxx":value}, {}, ...]
+
         constraints_force : list of dictionaries
             list of force constraints from the analysis.
             [{"Object":force_obj, "NodeLoad":value}, {}, ...
@@ -291,6 +295,9 @@ def __init__(self, analysis):
         self.cons_fixed = self.get_several_member(
             "Fem::ConstraintFixed"
         )
+        self.cons_rigidbody = self.get_several_member(
+            "Fem::ConstraintRigidBody"
+        )
         self.cons_force = self.get_several_member(
             "Fem::ConstraintForce"
         )