FEM: constants, use new module in elmer and ccx

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

@@ -63,6 +63,9 @@ class FemInputWriterCcx(writerbase.FemInputWriter):
             self.dir_name,
             "{}_inout_nodes.txt".format(self.mesh_object.Name)
         )
+        from femtools import constants
+        from FreeCAD import Units
+        self.gravity = Units.Quantity(constants.gravity()).getValueAs("mm/s^2")
 
     def write_calculix_input_file(self):
         timestart = time.process_time()
@@ -1095,9 +1098,10 @@ class FemInputWriterCcx(writerbase.FemInputWriter):
             f.write("** " + selwei_obj.Label + "\n")
             f.write("*DLOAD\n")
             f.write(
-                "{},GRAV,9810,{},{},{}\n"
+                "{},GRAV,{},{},{},{}\n"
                 .format(
                     self.ccx_eall,
+                    self.gravity,
                     selwei_obj.Gravity_x,
                     selwei_obj.Gravity_y,
                     selwei_obj.Gravity_z

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

@@ -35,6 +35,7 @@ from FreeCAD import Units
 from FreeCAD import Console
 import Fem
 from femmesh import gmshtools
+from femtools import constants
 from femtools import femutils
 from femtools import membertools
 from .. import settings
@@ -60,10 +61,10 @@ UNITS = {
 
 
 CONSTS_DEF = {
-    "Gravity": "9.82 m/s^2",
-    "StefanBoltzmann": "5.67e-8 W/(m^2*K^4)",
-    "PermittivityOfVacuum": "8.8542e-12 s^4*A^2/(m*kg)",
-    "BoltzmannConstant": "1.3807e-23 J/K",
+    "Gravity": constants.gravity(),
+    "StefanBoltzmann": constants.stefan_boltzmann(), 
+    "PermittivityOfVacuum": constants.permittivity_of_vakuum(),
+    "BoltzmannConstant": constants.boltzmann_constant(),
 }