WHAT’S NEW IN SIMCENTER 3D STRUCTURES 2021
This is our first blog on the new features in Simcenter latest release. We will continue such blogs in future as we do for Femap. New feature release is a continuous process throughout the year. Usually these features are released in patches as Simcenter 2021.x where x =1,2,3 etc. We are not mapping functional feature with the patch number. However, the latest patch number includes all the new features for given release. This blog covers Nastran Non Linear, Nastran Topology Optimization and Simcenter 3D process simulation which is additive manufacturing.
Monitoring improvement in 401 and 402 solution sequences
Non linear is an expensive, iterative and incremental process. Waiting for hours to solve only to get unacceptable results may result in poor efficiency. Moreover, it makes sense to improve the model if it behaves poor in convergence. Now it is possible to monitor the job in the middle of simulation both for results and convergence. User can check contours, animations, convergence plots as well as data on the fly.

- Strain free element addition in solution sequence 401
One efficient way to incorporate non linear geometry effects is by adding elements in middle of simulation to add stiffness. While this feature preexisted in Sol 401, it has been enhanced to add strain free elements as well. It can be used to invoke effects of 1D springs or bushings introduced in the middle of simulation.

- Super element support for solution sequence 402
Its not true that all the components of a multi-step model have a non linear behavior. Some parts may behave linear if they have a bonded contact at interface. Such components can be modeled using super elements to reduce the size of model from computational perspective. Super elements are modeled using Simcenter Nastran SOL 103.
- Creep limit control in solution sequences 401/402
Creep is a very slow process. It takes weeks to see the effect of creep in real life problems. And the process is non-linear as well with complex material behavior. It is not possible to solve a non-linear problem in real time with such a large clock time with fine and small increments size. The CRLIMR adaptive time increment scheme recently introduced allows user to define maximum creep strain per time increment. As a result solver takes big time steps when creep effects are less and significantly cut backs on time steps when creep is predominant.

- Restart improvement in solution sequence 401
Restart now includes RFORCE entry to support rotations effects such as angular velocities and accelerations. This enhances application of restart in turbines industry. Previously center of rotation was defined using node that was taken as change in model and resulted in restart failure. In 2021 release, center of rotation is defined a point coordinates to fix the earlier problem.

- Improvement in topology optimization
The stress response when used as constraint results in very large solution time. A new formulation to manage stress as constraint has been introduced to enhance performance.
- Improved compensation in additive manufacturing
Traditional digital solutions for AM did not include simulation. The simulation piece has been developed to predict and compensate for the deformations of the AM process. In 2021.1 use could choose only one compensation factor applied to all nodes. In 2021.2 an iterative scheme is introduced to apply compensation independently on each node.
