Prior to this release, the double-sided target surface option (KEYOPT(8) = 1 of the TARGE170 element) is only valid only for the Gauss detection (KEYOPT(4) = 0 of the CONTA174 element) and "Normal from contact nodes" (KEYOTP(4) = 1,2 of CONTA174 element)). Now, the double-sided target surface option is also valid for "Projection-based method” (KEYOTP(4) = 3,4 of CONTA174 element and “Unified approach” (KEYOPT(4) = 5 of CONTA174).

Contact detection for the double-sided target surfaces is also refined to prevent missing constraint equations or bad crossing constraint equations for the MPC contact definition, greatly improving contact solution accuracy and robustness.

For more information, see see Double-Sided Target Surfaces in the Contact Technology Guide.

Selecting a constraint type for assemblies is problem-dependent and can have a significant impact on solution accuracy. In this release, the constraint type detection logic (KEYOPT(5) = 2 of target element) has been revised so that larger percentages of assembly models can be solved with improved robustness and accuracy, in particular for mixed constraint types (solid-to-solid, shell-solid, shell-to-shell) defined within a contact pair. For more information, see "TARGE170 Input Data" in the Element Reference.

To help resolve overconstraint conditions, penalty (KEYOPT(2) = 1) and augmented Lagrange multiplier (KEYOPT(2)=0) formulas are introduced to rigid and force-distributed types of surface-based constraint. They are suitable to relax constraint on surfaces nodes. These two formulae are also available to build spot weld connections using 3D node-to-surface contact element CONTACT175.

Physical time (for scaled wear analysis) is added into the non-linear history file, for fretting fatigue and bolt self-loosening problems where a map between simulation and physical time is needed. The total mechanical (EPTO) and total strain (EPTT) are also added in the solution tracking variable list.

The contact data tracking file (CND) format is changed for easy contact diagnosis. The convergence status and maximum penetration element (contact/target side) are added, and column values are rearranged with acronym on the top. The new CND format is easy to export into other plot forms.

Contact detection robustness has been improved by adding further checks for potential spurious contacts in cases when the default pinball may be too large. This is expected to improve both accuracy and robustness of non-linear contact problems.

The INTER194, INTER195 3D gasket elements with thin solid option (KEYOPT(2) = 2) now support nonlinear material behavior based on ductile damage, in addition to von Mises plasticity.

For structural analysis, reinforcing elements (REINF263, REINF264, REINF265) allow temperature input using both mesh-independent and standard methods. Design changes were made to elements (MESH200, REINF263, REINF264, and REINF265) and loading commands (BFE, BF, and BFPORT) to support this feature.

The FOLLW201 element with KEYOPT(1) = 2 is now supported to specify load properties with the SFCONTROL command.

Material curve-fitting now supports shape memory alloy material models. Shape memory effect and super elasticity options are supported with uniaxial and biaxial test data.

ViscoElasticity fitting can involve multiple sets of experimental data at different temperatures for Shear and Modulus Bulk Decay. Partial solver options are now supported to address this situation with a multistep solution approach. The TBFT command can be issued to initiate the solves as needed (shear terms, bulk terms, and/or all experimental data). See Partial Solve Options Example for Prony Series Models for an example.

In material curve-fitting, AI-based automatic initialization (TBFT,AINI) of creep material parameters is now supported. For more information, see Creep Material Models and Initialize the Coefficients.

An example has been added to the Programmer's Reference to provide information on how to set up a UserMat API in C or C++.

You can now use the ductile damage model with INTER194 and INTER195 3D gasket elements with thin-solid option (KEYOPT(2) = 2: through-the-thickness, in-plane membrane, and transverse-shear deformation).

SMART crack-growth simulation now supports tabular loads, including those where ELEM and/or NODE are primary variables for temperature, displacement, and pressure loadings. You can now update the load tables after a load step or restart command, but you must use the initial mesh-based node and element numbering and not the current mesh after any changes (when ELEM and/or NODE are used as primary variables). For additional information and limitations, see SMART Crack-Growth Assumptions and Limitations in the Fracture Analysis Guide.

Multithreading can be activated (using the -nt command line option) for HBM analysis to enable Shared-Memory Parallel (SMP) processing for core harmonic computations. This option can significantly improve the computation time for models with a higher number of linear degrees of freedom and/or harmonics. For more details, see HBM Analysis and Parallel Processing in the Harmonic Balance Method Analysis Guide.

Linear perturbation analysis is now supported for a component mode synthesis generation pass where the element results calculation is activated (Elcalc = YES on the CMSOPT command).

Mode superposition transient analysis now supports the specification of displacement and velocity initial conditions. This can provide more accurate results for the cases with non-zero initial displacement and velocity values.