Advantages of Adams Solver C++
Overall, the Adams Solver C++ provides almost identical modeling and simulation capabilities found in the FORTRAN solver. Minor differences are described in this section.
However, Adams Solver C++ provides several additional modeling and simulation capabilities not found in Adams Solver FORTRAN.
Modeling capabilities found only in the Adams Solver C++
This is partial list of the most important modeling capabilities found only in the C++ solver.
1. BEAM and FIELD objects.
These forcing massless objects support an optional geometrically non-linear formulation. This option improves the numerical results when the objects experience large axial loads.
2. Flexible body contact.
Flexible-rigid and flexible-flexible contact are supported.
3. Flexible body dynamic limit.
This option stabilizes the simulation by ignoring high frequency modes.
4. Multiple-node and no node location for MARKERs on flexible bodies.
MARKERs on flexible bodies can be located at arbitrary positions with multiple node IDs or no node ID specified. A marker with no node ID undergoes only rigid body motion of the flex body. A marker with multiple node IDs undergoes motion that is a weighted average of the motion on the nodes. The weight is based on the proximity of the marker position to the node.
5. Floating MARKER support on flexible bodies.
J floating markers from force elements can be specified on flexible bodies.
6. More general MFORCE definition.
FORTRAN solver only allows linear expressions.
7. Generalized constraints.
GCONs allow creating user-defined constraint equations easily.
8. Curve and Surface MARKERs.
New MARKER definitions on Curves and Surfaces allow crating complex constraint equations.
9. Richer set of symbolic expressions.
Three-dimensional expressions, AO expressions, unit vectors, delay expressions, clearance expressions and so on, are supported.
10. Exact partial derivatives in user-written subroutines.
Users may provide exact partial derivatives to speed up the simulation and improve the numerical results. FORTRAN solver only supports numerical differencing.
11. Implicit GSEs.
Users may specify implicit equations in GSE objects. FORTRAN solver only support explicit equations in GSE objects.
12. MOTION expressions depending on any state.
This feature allows creating a richer set of expressions for constraints.
13. DELAY function.
The DELAY function allow user to define delay differential equations in their models.
14. Clearance measures.
A set of functions for creating expressions to observe the gap between to geometric bodies during the simulation.
15. Native finite elements.
The FE_PART statement defines finite element beam elements using the ANCF formulation. These beam elements have distributed mass and contribute to the equations of motion.
16. Co-simulation Modeling
A co-simulation modeling interface is available to connect Adams model to external models from other simulation products like Marc, EDEM and so on. using co-simulation techniques.
Simulation capabilities found only in Adams Solver C++
This is a partial list of the main simulation capabilities found only in the C++ solver.
1. Exact linearization algorithm.
The C++ solver implements a state-of-the-art exact linearization algorithm that uses no numerical differentiation but a closed-form algorithm to find the minimal state-space representation putting the equations of motion into an ODE form. This algorithm was extended to support user-defined linearization states. This algorithm works in static and dynamics cases as well. The FORTRAN solver implements an algorithm with no user-defined states support and provides good results only in static cases.
2. Exact GTCMAT computations.
Based on an exact linearization algorithm, the GTCMAT computation in the C++ solver computes results also during a dynamic simulation.
3. Adams Controls.
When using Adams Controls, the C++ solver offers an additional bisection method in the System Import option.
4. SIMULATE/SETTLE.
The C++ solver offers a settle simulation. The settle simulation command solves for all differential states (keeping all other states constant) to find all time derivatives (of the differential states) equal to zero. In a few words, given:
find z (keeping q constant) such that
5. Delay differential equations.
Using the DELAY function, users can create and simulate Delay Differential Equations. Users can define variable delays depending on any state. For example:
6. HHT and NEWMARK integrators.
The C++ solver offers two integrators with proven efficiency for a class of models. Model having large flexible bodies usually benefit from these two integrators.
7. Activation and deactivation extensions.
A wider set of objects can be activated or deactivated using the C++ solver.
8. UMF package.
The C++ solver has options to use the UMF linear algebra package. This option is especially useful with large models.
9. SAVE/RELOAD extensions.
The C++ solver offers the option to save to a buffer in memory.
10. Multithreaded execution.
Three multithreaded subsystem are available: the Jacobian evaluation, the LU numeric factorization, and the results generation. The Jacobian evaluation is triggered by using the NTHREAD option in the PREFERENCES statement. The parallel LU factorization is triggered by setting the environment variable MSC_ADAMS_PARALLEL_CALAHAN. The parallel results generation is standard in the stand-alone version only.
11. Multithreaded execution of user-written subroutines.
Users have utilities to set parallel execution of user-written subroutines.
12. CBKSUB user-written subroutine.
The callback subroutine (CBKSUB) is meant for advanced users writing numeric-intensive user-written subroutines.
13. Adams-to-Nastran export.
The Adams-to-Nastran export is chaining tool that creates an equivalent MSC Nastran linear model at any operating point. The exported files are fully editable and ready for SOL107 and SOL108,
14. Co-simulation
A tool called Adams Co-Simulation Interface (ACSI) and MSC COSIM are available to setup and co-simulate Adams models with external simulation codes like MSC Marc and EDEM.
15. Real Time Simulation with Fixed Step Integrator
Real time simulations with fixed step integrator performed on real time operating systems.