New features, enhancements and changes since last release

Highlights

New module pygccx.tools with helper functions

tools.stress_tools
- get_mises_stress.
  Returns the mises stresses from given stress tensors.
- get_principal_stresses.
  Returns eigenvalues and eigenvectors from given stress tensors.
- get_worst_principal_stress.
  Returns the worst principal stresses from given stress tensors.
- get_principal_shear_stresses.
  Returns the principal shear stresses from given stress tensors.
- get_max_principal_shear_stress.
  Returns the max principal shear stresses from given stress tensors.
tools.Bolt
- Class to generate pretensioned bolts for bolted connections made from
  solid elements. Methods for evaluating section forces are also available.
  Have a look at examples/bolted_flange and check the docstrings of pygccx.tools.Bolt and all its members to learn more about generation of preloaded bolts.

New model keyword *DENSITY (model_keywords.Density)
New model keyword *DLOAD (model_keywords.Dload)
New model keyword *MPC (model_keywords.Mpc)
New model keyword *PRE-TENSION SECTION (model_keywords.PretensionSection)
New model keyword *HYPERELASTIC (model_keywords.HyperElastic)
New model keyword *TIE (model_keywords.Tie)
New model keyword *EQUATION (model_keywords.Equation)
New model keyword *INCLUDE (model_keywords.Include)
New model keyword *DEFORMATION PLASTICITY (model_keywords.DeformationPlasticity)
New step keyword *GREEN (step_keywords.Green)
Can also be used as a step keyword
New class model_keywords.Universal to write arbitrary strings to input file

Mew methods "to_pickle" and "from_pickle" in class Model to quickly
save and load the model from/to a pickle file
New methods in class CoordinateSystem to transform points, vectors or tensors
from one coordinate system to another or from / to global.
New method model.update_mesh_from_inp(filename, ignore_unsup_elems, clear_mesh)
for reading mesh, sets and surfaces from ccx input file.
New method mesh.add_sets(*sets)
for adding existing ISet instances to mesh.
New method mesh.add_node_surface(surf_name, nids)
for manual creation of node surfaces .
New method mesh.add_el_face_surface(surf_name, faces)
for manual creation of element face surfaces
New method mesh.add_surfaces(*surfaces)
for adding existing ISurface instances to mesh.
New parameter "no_cpu" in model.solve
for selecting the number of cpu's used during solve.
New parameter "load_inp" in model.show_results_in_cgx.
Loading of the inp file together with the frd is now optional

Stick slope "lam" is now be use also for TIED surface-to-surface contact in
model_keywords.group_funcs.make_contact. If omitted, normal stiffness k is
used as before
Placement methods (move, rotate_x, ...) in CoordinateSystem now return
"self" which enables method chaining.
E.g. csys.move().rotate_x().rotate(y)
Minor bug fixes and improvements all over the place.

Removed attribute "dim" from ISet.
Removed class ElementFace.
Element faces inside an IElement are now represented by nested tuples
Each face is a tuple with the node ids forming this face
(
(1, 2, 3), # face 1 of element, made up from nodes 1,2,3
(1, 3, 4), # face 2 of element, made up from nodes 1,2,4
)
Changes in method mesh.add_set(set_name, set_type, ids)
If a set with given name and set_type already exists,
ids are added to the existing set.