One of the biggest impediments to the use of digital simulation and analysis in product development is the disconnection between CAD and CAE. This disconnection creates process roadblocks that push simulation and analysis out of the design process, and relegate it to the role of late-stage validation, where it can provide little more than go/no-go feedback.
The disconnect has to do with the data flows between design and analysis tools. CAD and CAE models are distinct and different things. Only in the simplest of cases can a CAE model be derived automatically, or with minimal work, from a CAD model. In most cases, you start with the product definition geometry, massage it to create the geometry for building analytical models, then tune and optimize that data for analysis. In many cases, this process can be both time-consuming and expensive.
Too often, even minor design changes can break the linkages used to synchronize analysis models to design geometry. Analysts often end up completely rebuilding their analysis models whenever a design change occurs.
In an Ora Research white paper, Strengthening Simulation’s Business Impact, analyst Bruce Jenkins quotes an unnamed aerospace/defense executive on this theme: “Among the constraints on doing more detailed analysis earlier, the biggest one is figuring out how to construct the models quickly enough to be able to do the analysis quickly. So it isn’t the threat of a 6-hour solver run that’s holding you up; it’s how you are going to produce the geometric and finite element models fast enough that the 6-hour run does become the gating factor. If it takes you 6 weeks to prepare the input, the 6-hour run time is irrelevant. But if you can get the models ready in 15 minutes, the run time becomes significant. We would like to get to the point where the run time of the solver code is what’s holding us back.”
The solution to this problem doesn’t lie in CAD systems with integrated CAE. Often, those systems are little more than API integrations, with limited choices of solvers.
Jenkins notes that the consumer electronics manufacturers contacted during his research typically used on the order of a half-dozen key simulation applications, compared with 30 or more in automotive powertrain, and 100 plus for major aerospace projects.
This array of disparate, specialized CAE tools creates redundant data and workflows, which ultimately multiplies impediments caused by the disconnection between CAD and CAE.
If there is a solution to this problem, it may be in creating an integrated environment that cannot just help in creating analysis models, but also manage the relationships between the disparate models used for design and analysis. Possibly something like NX Advanced FEM, from Siemens PLM.
Advanced FEM is a standalone multi-CAD finite element modeling and results visualization application, designed to meet the needs of experienced CAE analysts. While it has similar capabilities to other FEM applications, there are at least three major capabilities in NX Advanced FEM that, combined, make it standout from the crowd.
NX Advanced FEM is built on the NX CAD platform, which includes Siemens’ Synchronous Technology, supporting both history based modeling and direct modeling, and making it ideal for working in a multi-CAD environment.
Because of Synchronous Technology, NX Advanced FEM can read in foreign CAD models and assemblies (direct geometry translators are available for CATIA V4, CATIA V5, and Pro/E), and edit them intelligently, irrespective of how they were originally built.
Direct modeling, in general, has become widely popular for CAE model cleanup and simplification, because it doesn’t force the analyst to figure out how the original model was built in order to work on it. Further, the analyst only needs to learn a few commands to accomplish what they need. They don’t need to become a CAD expert.
It is Synchronous Technology’s ability to re-parameterize models with driving dimensions that sets it apart from other direct modeling systems. When analysis results demand design changes, these can be applied quickly and easily, with no need to go back to the source CAD data (and no need to rebuild the analysis model).
In NX Advanced FEM, design and analysis models are completely associative to each other. This means that NX can update analysis topology as design changes are made. Because it is possible to have many analysis models driven from one design model, the time saved from not needing to rebuild those analysis models can be substantial.
Siemens PLM sells a pretty wide array of solvers. But serious CAE users want to make their own choices of what solver to use. NX Advanced FEM is open by design, supporting many third-party solvers, including Nastran, Ansys, Abagus, LS-Dyna, Recurdyn, Adams, and more. Further, it’s designed to make the process of integrating other solvers easy.
There is far more to NX CAE and NX Advanced FEM than direct modeling, model associativity, and multi-solver support. It is a substantial system, and its support for multi-discipline simulation and optimization, system-level simulation, and simulation data/process management are key capabilities.
Yet it is the combination of direct modeling, model associativity, and multi-solver support that really addresses the disconnect between CAD and CAE, and sets NX Advanced FEM apart from the competition. Though the program is most at home in an NX CAD environment, it will work well in multi-CAD, CATIA, or Pro/E environments too.
Siemens PLM Software