CM2 FEM® SDK /release 5.6.0

• Lib names now end with _56 (Windows®), 5.6.0 with symlinks from 5.6 (Linux®, macOS®).
• New builds with clang 20 and gcc 15.1 on Linux (Fedora 42).
• Visual Studio 2015 deprecated (will be no longer provided in future versions).

fem::law_shell_solid

• New law for Mindlin shells and plates based on a solid constitutive law (any fem::law_solid_stiff), two thickness abscissas (bottom and top) and a number of Gauss points along the thickness for the numerical integration.
  Can be associated to any plate/shell mechanical model (fem::model_plate_lin, fem::model_shell_lin, fem::model_plate_gnl, fem::model_shell_gnl).
  Caveats: no specific mass law (use standard fem::law_scalar or fem::law_shell_mass).

fem::law_shell_laminated

• New law for laminated (aka. multi-layer) Mindlin shells and plates based on several solid constitutive laws (any fem::law_solid_stiff).
  Can be associated to any plate/shell mechanical model (fem::model_plate_lin, fem::model_shell_lin, fem::model_plate_gnl, fem::model_shell_gnl).
  Optimal transverse-shear coefficients are automatically computed (different from the usual 5/6 coeffcient for homogeneous plates/shells).
  Caveats: no specific mass law (use standard fem::law_scalar or fem::law_shell_mass).

fem::Cauchy_stresses

• Updated to support the numerical models based on the new fem::law_shell_solid or fem::law_shell_laminated laws above.
  Caveat: the computations of the Cauchy stresses are still based on the linear elastic theory (=> results are approximated for geometrically non-linear models and for models with plasticity).

fem::solver_least_squares

• Updated to smooth the plasticities of numerical models based on the new fem::law_shell_solid or fem::law_shell_laminated laws above.
  Caveat: the computed plasticities are the smoothed values of the max plasticities out of all plies (only one returned plasticity per node).

fem::link_surface

• New model for rigid links (DISPLACEMENT, ROTATION or TEMPERATURE) between a set of nodes and a surface (plane 2-D or 3-D).
  This new class is intended to make junctions between incompatible surface meshes.
  👉 May require usage of meshtools2d::get_elements_containing_nodes of the CM2 MeshTools SDK.

fem::link

• Now supports also the TEMPERATURE field (i.e. can be used to link temperatures).

fem::law_membrane_skyline

• New fem::law_membrane_skyline for full (skyline profile) user-defined membrane elasticity law.
  Similar to fem::law_shell_skyline and fem::law_solid_skyline.

fem::spring, fem::spring_directional, fem::hinge_punctual

• Error when associated to a fem::law_scalar_nl with null-stiffness range(s).
  Regression since version 5.5.0.

fem::law_beam_StVenant

• Errors on loads with offset in the constitutive law.

fem::post_processor_1d

• Errors in stress diagrams on beams with punctual load(s) at end of element (s = +1).

fem::solver_static_Newton

• Convergence issue with multi-step loadings together with elasto-plastic laws.

fem::Cauchy_stresses

• Errors on shells with offset in the constitutive law.

fem::law_scalar_ep_piecewise_linear, fem::law_rod_ep_piecewise_linear, fem::law_solid_ep_piecewise_linear

• Error when last value of Es was DBL_MAX (or similarly large).

fem::numerical_model_base

• Member get_local_basis replaced with get_centre_and_local_basis (gaining a DoubleVec3& G parameter for the centroid of the element).
  The centroid and the basis are computed taking into account the hard offsets if any.

fem::solver_static_Newton

• The default value for settings_type::min_E is raised from 1E-16 to 1E-12.
  The former threshold was too low sometimes for the solver to declare convergence when starting from solutions already equilibrated.

fem::solver_least_squares

• Plates/shells: for physics_kind = FEM_NODES_VON_MISES, FEM_NODES_VON_MISES_SIGNED, FEM_NODES_TRESCA, FEM_NODES_TRESCA_SIGNED, the computations are now smoothing the max values of these stress scalars along the sections/thicknesses (used to smooth the values of these scalars along mid-section line and mid-surface).

fem::Cauchy_stresses

• New requested parameter const DoubleMat& pos for the coordinate matrix of the nodes.

fem::context

• Member set_min_penalty_factor (resp. get_min_penalty_factor, set_max_penalty_factor, get_max_penalty_factor) renamed to set_min_penalty_stiffness (resp. get_min_penalty_stiffness, set_max_penalty_stiffness, get_max_penalty_stiffness).

fem::medit_nodal

• Overloads replaced with fem::vizir_nodal, fem::vizir_nodal_scalars, fem::vizir_nodal_vectors, fem::vizir_nodal_tensors.