Robust convergence for rigid bodies and couplings:                                                               2022xFD04

The reference nodes of rigid bodies and couplings are not treated as general nodes anymore for the residuals convergence. A weighted factor has been introduced in the denominator. This factor (f) has a default value of 1 if the node is not a reference node. In case of reference node, the f value increases monotonically with increase in number of dependent nodes. So for a given nodal residual force, the scaled residual goes down thereby reducing the normalized residual value. The tolerance remains the same as in prior releases which is 5e-3.

Ø  More control over frictional contact                                                                                    2022xFD04The equivalent slip rate definition has been modified by splitting slip rate between filtered and unfiltered slip rate. The modified equivalent slip rate is as follows:

The ὠ is the user input that has a default 0.9 value. In case of explicit frictional contact problems, the stress noise can be reduced by reducing the value of this user parameter.

• Contact mass scaling                                                                                                                2023xGA

Penalty stiffness is introduced by default in explicit to account for more accuracy. However, with increase in stiffness the stable time increment reduces thereby increasing solve time. The contact mass scaling has been introduced to make solver run faster in such situations.

Note: Users are encouraged to use general contact instead of contact pair for explicit even in cases in which number of contact pairs are less. The contact pair in explicit has performance and accuracy not at par with general contact. All the future developments are more focused in general contact in case of explicit.

Note: Users are discouraged from using node based surfaces in node to surface contact. The node based surface is a collection of nodal points used to define a surface. If results in lots of contact pressure noise if used in conjunction with node based surface.

• Valanis Landel Model                                                                                                               2022xFD04

 We are not going in its detail as the model was introduced a year earlier in standard. It is a modified Marlo model in which the test data can be given in tension as well as in compression. In 2022x release this model has been introduced in explicit as well.

• Anisotropic Hyperelasticity Update                                                                                       2022xFD04

Two new models in this space have been added. One is Holzapfel-Ogden model for myocardium modeling. It is available in standard and explicit. Cardiac muscle tissues can be modeled with this this type of anisotropic behavior.

The second one is Kaliske-Schmidt model for anisotropic response of reinforced polymer materials. Its available in standard and explicit and it can be imported as well.

• Adhesive curing enhancements                                                                                             2022xFD06

This model was introduced in collaboration with 3M in 2021x. It models the effects for curing parameters such as curing temperature, cure rate on the residual stresses and warpage predictions for adhesives. More element types are now supported, more procedures are supported and better diagnostics. New outputs such as shrinkage strain, degree of sure and rate of degree of cure have been added.

• CAP Plasticity with relative density                                                                                       2022xFD04

The Drucker Pager model has been enhanced to include relative density. Material properties can be defined as a function of relative density. Useful in tablet compaction process in the pharmaceutical industry. No subroutines are required now for such kind of material modeling.

Explicit Dynamics Enhancements 2023x and 2022xFD’s

• REBAR Reinforcement for beams                                                                                          2023xFD01

The beam elements can now have stiffness defined through rebars. The feature has been available through *REBAR definition. Now the same feature is available in *BEAM SECTION  through *REBAR LINE within the beam section. REBARS are very useful in civil and construction for concrete models.

• SPH Enhancement                                                                                                                     2022xFD04

The default SPH element conversion method changed from element based to background grid based method. It is beneficial in cases of high aspect ratio parent elements. The element based method given non uniformly distributed particles.

• ALE Enhancement                                                                                                                      2023xFD01

Adaptive Smoothing in ALE domain has been expanded to parallel domains for improved performance in Abaqus explicit. Contact pair limitation still exist as general contact cannot be used in adaptive regions.

Please stay tuned for out next blog on 2023x updates.