Prior to this release, only the variational range of the normal contact stiffness can be controlled. In this release, the variational range of the tangential contact stiffness can be controlled as well. The default method of updating the tangential contact stiffness (KEYOPT(13) = 0) is suitable for most applications. However, the new option improves nonlinear convergence in complex frictional contact models.

Selecting a constraint type for assemblies is problem dependent and can have a significant impact on the solution. In this release, the automatic constraint type detection logic (KEYOPT(5) = 0 of target element) has been revised so that larger percentages of assembly models can be solved by default with improved robustness and accuracy. For more information, see "TARGE170 Input Summary" in the Mechanical APDL Element Reference.

Defining a Pre-meshed Body as a Rigid Body with RBGEN

In most applications, rigid bodies are modelled as discretized finite elements in a meshed body. The rigid body can be defined on the exterior of a pre-meshed body discretized by solid, shell, and beam elements (called underlying elements).

From this release onward, a new RBGEN command automatically generates rigid target elements exterior to given element components along with a pilot node (TSHAP,PILO), and adds rigid nodes defined as pin-type or tie-type nodes using nodal components using TSHAP,POINT.

This command enables you to define a rigid body with one Mechanical APDL RBGEN command. It is helpful when converting a flexible body to a rigid body. It also reduces the input file size where rigid target elements are written as longlist using EBLOCK.

Tie and Pin node

This release introduces tie-type node and pin-type nodes to rigid body definition. Tie nodes include both translational and rotational degrees of freedom. Pin nodes only include translational degrees of freedom. Define a node segment as a pin node with KEYOPT(7) = 1 in the target element. Define a node segment as a tie node with KEYOPT(7) = 0 in the target element.

Global Pinball for Contact Trim

When working with large assembles and an excessive number of bonded or small sliding or symmetric contact/target elements, trim is a useful tool to reduce the model size. This release introduces "global pinball" in the CNCHECK command. This tool enables you to quickly apply the same pinball value to all the selected contact pairs during the trim process.

Auto-trim in Contact Split

Starting from this release, the CNCHECK,DMP command performs additional contact trim before the contact split operation. This is aimed to reduce contact split operation time and further reduce model size in solution runs.

Fluid pressure penetration loads are used to model when surrounding fluid or air penetrates into the contact interface from one or multiple locations based on contact status. The fluid penetration path detection algorithm has been improved to significantly reduce the computational time for three dimensional problems with fluid penetration pressure loads.

The performance of models with contact surface wear (TB,WEAR), where wear is modelled for post-processing purposes only and does not affect the solution (by defining TBDATA,C5=- 99), is improved when using contact surface splitting (CNCHECK,DMP).

A new joint element is available with relative rotations defined by the 3-1-3 Euler angles. Use the new MPC184-Genb joint element to connect two bodies to transmit motion from one body to another. Stiffness and damping behavior, locks and stops, joint loads and boundary conditions can be specified for this joint as needed.

You can now use the energy-based and location-based criteria with mesh-coarsening in a nonlinear adaptivity analysis. The added capability enables you to apply mesh-coarsening on unnecessarily fine meshed regions or on regions with no critical features. Coarsening remeshings of debonding problems (cohesive-zone material) using the contact-based criteria have been improved, especially for subsequent remeshings. For more information, see Nonlinear Mesh Adaptivity in the Nonlinear Adaptivity Analysis Guide.

You can now use the new element-removal-based criterion (NLADAPTIVE,,,REMELM) to remove elements from a deformed body in a nonlinear adaptivity analysis. The added capability determines which element(s) to remove based on the maximum equivalent strain measure or maximum principal strain measure of the element(s). This feature also allows you to manually define the candidate elements for removal. You can use the new NLMESH,DCON control to generate contact and target elements in gaps created in the element removal process. For more information, see Nonlinear Mesh Adaptivity Criteria in the Nonlinear Adaptivity Analysis Guide.

The LINK228 3D Coupled-Field Link element with KEYOPT(1) = 101 and 1001 is now supported for the direct-embedding workflow. For more information, see Direct-Embedding Workflow in the Structural Analysis Guide.

A new MSHOPTIM command is available for automatic mesh optimization. This action command tries to generate an optimum base mesh in the selected mesh region based on the cross-sectional sizes of intersecting embedded elements. The optimized base mesh can be used in subsequent reinforcing or direct element embedding modeling approaches to overcome simulation accuracy issues.

Perform preprocessing-level stress evaluation of structural 3D shell elements using the new EENS command. This action command calculates element results (such as strains and stresses) based on the curvature that is caused by bending or twisting. Membrane deformation is ignored. This command can be used to evaluate element solutions without running a regular finite element simulation, which may be useful during the design phase of a product that requires frequent shape changes.

You can now use coupled pore-pressure-thermal mechanical solid elements (CPTnnn) as base elements in a reinforcing analysis using the mesh-independent method.

The OSRESULT command for controlling the output quantities written to the database has been enhanced. New Item and Component labels have been added for more robust result-data control.

The INTER194 and INTER195 3D gasket elements with thin solid option (KEYOPT(2) = 2: through-the-thickness, in-plane membrane, and transverse-shear deformation) now support von Mises plasticity models with isotropic hardening or kinematic hardening (TB,CHABOCHE; TB,NLISO or TB,PLASTIC).

AML Python Module is the Python extension for Ansys Materials Lab (AML) that allows you to access Ansys structural materials to:

You can use AML Python Module for parameter studies, yield surface generation, and on-the-fly stress generation. You can also develop your own parameter fitting tools by creating custom experiments and using SciPy-like tools for optimization.

For more information, see Using AML Python Module in the Material Reference.

All material curve-fitting now occurs via the Ansys Materials Lab (AML) framework and adheres to the same command structure.

Support is now available for anisotropic hyperelastic material models. Anisotropic hyperelasticity allows for uniaxial, biaxial, and volumetric loading conditions with load-direction information.

Creep models (with elasticity) now support both creep strain data-fitting and uniaxial loading.

AI-based parameter initialization is now available for Prony series models with shear modulus and/or bulk modulus data in both time domain and frequency domain using the nearest-neighbor method. An optional feed-forward neural network method for obtaining a starting point for the nonlinear regression process is also available.

For more information, see Material Curve-Fitting in the Material Reference.

Due to the nonlinear behavior of hyperelasticity-based finite-strain material models, initial deformation cannot be directly defined consistently via initial stresses. Now, however, you can apply an initial-deformation gradient to indirectly define an initial-stress state for those material models. A typical application for the initial-deformation gradient involves an acoustic or fluid-structure interaction (FSI) analysis where the correct stiffness of a hyperelastic material in an updated deformed configuration is required. For more information, see Applying Initial Deformation Gradient in the Advanced Analysis Guide.

When specifying time-stepping parameters in a cyclic-loading analysis, you can now modify default time-stepping and predictor behavior when appropriate for a given analysis (for example, when many closely-spaced defined time points are needed to describe the loading and a smooth transition occurs from one defined point to the next). For more information, see Step 5. Specify Time-Stepping Parameters in the Advanced Analysis Guide.

Cyclic-loading and cycle-jump analyses now support multiframe restart without the need to redefine and reapply cyclic-loading tables. A multiframe restart can resume a job at any point in a cyclic-loading or cycle-jump analysis for which information is saved. For more information, see Restarting a Cyclic-Loading Analysis and Restarting a Cycle-Jump Analysis in the Advanced Analysis Guide.

A new ADPCI command option (Action = FCRI) enables you to define an inline material criterion for initializing a crack. The new capability overrides the crack-initiation criterion defined via the material data table (TB,CRKI) and ADPCI,DEFINE,,,MATID.

You can now use von Mises plasticity models with isotropic hardening or kinematic hardening (TB,CHABOCHE; TB,NLISO or TB,PLASTIC) with INTER194 and INTER195 3D gasket elements with thin-solid option (KEYOPT(2) = 2: through-the-thickness, in-plane membrane, and transverse-shear deformation).

The SMART crack-growth method now supports displacement boundary conditions applied to nodes with their nodal coordinate systems rotated (specified via NROTAT, NMODIF, NANG, or NORA). The node rotations and boundary condition values are properly mapped during remeshing.

Note that any rotations of nodal coordinate systems are maintained inside the remeshing zone only if those nodes are associated with a displacement boundary condition. Otherwise, the nodal rotations are not maintained during remeshing, and any new node is set with the default nodal coordinate system.

The SMART crack-growth method now tracks and updates user-defined components when the component update key is activated with the CM,,,,,KOPT=1 command, but only for solid element and surface node components. This feature enables you to adjust or revise the loading parameters as needed over an element or node component after remeshing. For additional information and limitations, see SMART Crack-Growth Assumptions and Limitations in the Fracture Analysis Guide.

The harmonic balance method (HBM) cyclic analysis enables efficient calculation of multiharmonic forced responses for cyclically symmetric systems with local nonlinearities. This technology calculates the steady-state responses of cyclically symmetric structures to engine order (traveling wave) type excitation. A traveling wave excitation can be applied as nodal forces or as surface pressure loads. Macros are available to facilitate modeling of the cyclically symmetric structure using single stage (MSOPT) cyclic superelements with different spatial harmonics generated from single sector models. Use an HBM cyclic analysis to simulate the effects of nonlinearities (including contact interfaces) as well as prestress (such as rotational velocity, temperature, and contact pressure) in rotating and turbo machinery. See HBM Cyclic Procedure in the Harmonic Balance Method Analysis Guide for more details and examples.

The fixed-interface component mode synthesis (CMS) method can now be applied to single stage (MSOPT) sector models. Prestress effects can be included using the linear perturbation substructuring procedure. CMS for single stage is an efficient way to reduce the size of a cyclically symmetric model and thus significantly reduce the solution time (use pass) in advanced workflows. See the Substructuring Analysis Guide and the Multistage Cyclic Symmetry Analysis Guide for details about the procedure.