The Siemens Community Catalyst program was co-created with our community to acknowledge technology leaders who consistently contribute to the Siemens Community. Nominations are accepted on a rolling basis.
Hi,
I have an issue with cut approach (https://altairuniversity.com/learning-library/radioss-sub-modeling-cut-approach/).
I'm modeling an half of full vehicle with the cut approach above. From this sub-model, with hyperstudy I modify a little bit the geometry and study how the crash changes dynamic. I wonder how dynamics could vary among runs if the section-force imposes original displacements?
Many Thanks
if the geometry changes significantly it is possible the crash dynamic also varies from the original in:
It is difficult to estimate how much submodel affects the global model. This is why the reanalysis of the optimized global model is recommended.
RD-E: 5400 Cut Methodology Conclusion (from Radioss help):
The cut methodology allows you to reduce the computation time by running smaller models once a first full model has been run. Its main limitation lies from the fact that the interactions between the selected parts (for sub-model) and the unselected parts must be small enough so that the behavior of the unselected parts is not significantly affected by unselected parts. Therefore, the interactions between the unselected parts and the selected parts (for sub-model) could be well defined by the section (no extra contact for instance). To assess those hypothesis, it is also important to compare the section force (or moment) between full model and sub-model. In industrial applications, like in dummy analysis, it is advised to keep only the dummy and its direct environment as sub-model. Then about 90% of the CPU cost could be saved compared to the full car model. In low speed impact or beginning of impact with high speed, it is advised to keep only the deformed area as sub-model. Then about 30% of the CPU cost could be saved compared to the full car model.
The cut methodology allows you to reduce the computation time by running smaller models once a first full model has been run. Its main limitation lies from the fact that the interactions between the selected parts (for sub-model) and the unselected parts must be small enough so that the behavior of the unselected parts is not significantly affected by unselected parts. Therefore, the interactions between the unselected parts and the selected parts (for sub-model) could be well defined by the section (no extra contact for instance).
To assess those hypothesis, it is also important to compare the section force (or moment) between full model and sub-model.
In industrial applications, like in dummy analysis, it is advised to keep only the dummy and its direct environment as sub-model. Then about 90% of the CPU cost could be saved compared to the full car model. In low speed impact or beginning of impact with high speed, it is advised to keep only the deformed area as sub-model. Then about 30% of the CPU cost could be saved compared to the full car model.
ok, let's suppose for instance that my changes were about thickness on the front rails for my vehicle. Thickness varies within few millimiters (about 3mm), but when It's thin, the car folds deeply against the wall, whereas if It's thick, the car folds a little and then has a rebound. With the cut approach I have imposed the displacement to the section force so that the car's dynamic is fixed, isn't it? In this way, I cant't appreciate differences due to the thickness changes, can I?
(Total mass isn't very affected from thickness changes (less than 1%), but stiffness might be)
Many thanks again for your reply
With the cut approach I have imposed the displacement to the section force so that the car's dynamic is fixed, isn't it? In this way, I cant't appreciate differences due to the thickness changes, can I?
yes to both questions
Join us for a community conversation on how High-Performance Computing (HPC) and Simcenter PSIM work together to meet the increasing demands of modern power electronics simulation. During this one-hour technical session, you'll discover how leveraging HPC can speed up simulations, improve scalability, and empower engineers…
Join us for a community conversation on accelerating your motor simulation workflow with Simcenter Simlab. In this beginner-friendly session, we'll introduce the platform's automated model-building capabilities and show how easy it is to set up your first electric motor analysis. You'll see the basic steps of geometry…
Join us for a Community Conversation where we'll discuss practical approaches to analyzing complex electromagnetic models using hybrid solver techniques. This session will provide a general overview of how different computational methods can be combined within a single simulation to address models containing varied…
